Gwynzer / Reddit

A 30-inch-long deep-sea bug? This picture purporting to show a deep-sea isopod, of the species Bathynomus giganteus, has been posted to sites such as Reddit and Cruisers Forum.

It may look like a creepy-crawly April Fool's joke - but an expert on deep-sea species says the bizarre giant bug shown in pictures circulating on the Internet is the real deal.

"I've seen the pictures, and they are real, and they really do get that big," Craig McClain, assistant director of science for the National Evolutionary Synthesis Center in North Carolina, told me today.

McClain specializes in deep-sea biological systems and covers the subject on his Weblog, Deep-Sea News. So he was the go-to guy when pictures of the bug, reportedly hauled up aboard a remotely operated vehicle operating near an oil rig in the Gulf of Mexico, started turning up on Web sites ranging from Reddit to Cruisers Forum.

"It's an isopod," McClain said. "It's like the rolypolys or pillbugs that you find in your garden. It's the same group of animals."

But this deep-sea isopod is no pea-sized rolypoly: The critter grows to a size of 20 inches or more. The bug shown in the pictures that are currently making the rounds is on the "larger size" of the spectrum, measuring 30 inches in length, McClain said. But there are a lot more big bugs out there.

	MSNBC
	Click for video: See the giant isopod in action.

"They're really common in the deep water in the Gulf of Mexico," he said.

That's where this specimen of Bathynomus giganteus was said to have been found. The story has been pieced together over the past few days, from reports bubbling up on the Internet forums: The bug was a hitchhiker that apparently latched onto an ROV operating around Seadrill's West Sirius rig in the Gulf of Mexico, at a depth of about 8,500 feet. One photo taken from the side and another displaying a full-frontal view were posted via Reddit late last week by a member who said he works for "a sub-sea survey company."

McClain said he received the pictures himself from a researcher who has been active in the area. "We're sort of an online clearinghouse for that sort of thing," he said. My efforts to contact McClain's source via e-mail were unsuccessful, however.

The circumstances of the story definitely raised warning flags: It's hard to put your finger on exactly who is providing the images. The shots of the bug don't provide a definitive sense of scale. And April Fool's Day, prime time for Internet pranks, is just around the corner. But McClain told me everything he's seen so far matches up with what he knows about giant isopods.

"It's definitely not an April Fool's joke," McClain said.

I'll take his word on that. And no matter what you think about the latest pictures, Bathynomus giganteus is no joke. The species was discovered and first described more than a century ago by French zoologist Alphonse Milne-Edwards, and the Smithsonian's National Museum of Natural History has a nice big collection of giant isopods.

One YouTube video shows an isopod walking along the seafloor, and another shows the carnivorous bug vying with eels and crabs to chow down on tunafish.

McClain and his colleagues at Deep-Sea News have frequently written about the bug. Here's a smorgasbord of Web links:

• When isopods attack!
• Why is the giant isopod giant?
• Isopods in their native element
• The science of everything and giant isopods
• Cosmos magazine: Dwarfs and giants (PDF)

Speaking of smorgasbords, I couldn't help but notice that some sources claim the giant isopods are "something of a delicacy" in Taiwan, where they are boiled and served with rice at oceanside restaurants.

If those reports are true, that would be one thing McClain didn't know about one of his favorite deep-sea monsters. "I've never heard of anybody eating them," he said.

More about deep-sea creatures:

• Giant squid captured on video 
• 10 deep-sea secrets revealed
• Thousands of new species found in deep sea
• Giant marine life found in Antarctic waters

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."

• Nature: The human genome at 10
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• Gadget Lab: Gallery of Rube Goldberg contraptions
• Planetary Radio: The busiest man in space exploration?
• IEEE Spectrum: Air Force launching secret flying Twinkie

History Channel

Click for video: A computer graphic shows Jesus' body underneath the Shroud of Turin, as reconstructed for "The Real Face of Jesus" on the History Channel. Click on the picture to watch an MSNBC video about the program.

Does the Shroud of Turin show the "real face of Jesus"? That claim is impossible to judge, even though it serves the title of a documentary about the 3-D analysis of the Shroud of Turin premiering tonight on the History Channel. What can be said is that the centuries-old image wasn't just painted freehand. Computer analysis of the imprint on the shroud suggests that it had to be left behind by someone draped in cloth.

"Is this the artifact of a real person or not? Definitely it is," Ray Downing, the digital illustrator at the center of the show, told me today.

Downing worked with specialists on the shroud to come up with a photorealistic representation of the man whose body's imprint appears faintly on a famous 14-foot-long length of linen. For some Christians, the stain serves as the miraculous snapshot of their risen Lord. For most scientists, it is a cleverly done fake from the 13th or 14th century, but nothing more.

	History Channel
	A rough computer model shows the 3-D face imprinted on the Shroud of Turin.

Back in 1988, carbon-14 dating tests were conducted on a sample from the shroud in an effort to determine whether the cloth was created in Jesus' time. The verdict from three laboratories was that the cloth was produced in medieval times. But the shroud's fans have insisted that the sample was actually taken from a patch, rather than from the original linen. Just this month, a chemist proposed a new series of non-destructive dating tests that would give an estimate for the entire cloth.

From a marketing perspective, the timing of the History Channel show couldn't be better: Good Friday and Easter Sunday, the Christian holy days that mark Jesus' death and resurrection, are just a few days away. What's more, the shroud is due to go on display for six weeks at Turin Cathedral, starting April 10. The last time the relic was exhibited, a decade ago, more than 3 million people came to Turin to see it. More than a million reservations have been received already for next month's viewing.

Have scientists been wrong about the shroud? Downing noted that historical records referring to the shroud predate the current carbon-14 estimate. "We know the carbon-14 [test] is wrong," he said. "The question is, how wrong are they? The further back you go, the less likely it is that anybody could have faked it."

History Channel

Digital illustrator/animator Ray Downing and John Jackson look at a high-quality replica of the Shroud of Turin, displayed at Jackson's research center in Colorado.

But the dating debate isn't the focus of Downing's work: Rather, he concentrated on what the shroud shows. Could the faint outlines preserved in the cloth match up with the outlines of a specific person? Downing found that they could, and he drew up a 3-D image that fit the data.

"It's just like how a police investigator will question an eyewitness, and from that information he can draw a complete sketch," Downing said. "The shroud is a silent witness. It's like the witness in an investigation."

Downing started out with high-resolution photographs of the shroud from the Holy Shroud Guild and the Shroud of Turin Research Project. "Between the two of them we were able to come up with a good image," he said.

He also consulted with John Jackson, a physicist who has come to specialize in studying the shroud at his research center in Colorado. Once all the imagery was computerized, Downing used software to massage the 2-D data into 3-D imagery.

History Channel

A computer reconstruction shows a body image that matches up with the faint imprint seen on the Shroud of Turin. The imagery was used to develop 3-D models.

3-D visualizations of the face in the shroud have been done before, but Downing found that the data couldn't be matched up with a realistic representation if he just added another dimension to the shroud's flat plane. The image looked more like a reflection in a funhouse mirror - and that's because the cloth had to be draped around the body's form to produce a match.

Downing said the cloth "encoded" the 3-D data on a 2-D surface. "It's as if there is an instruction set inside a picture for building a sculpture," he explained in a news release.

By manipulating the computer model, Downing matched up the shroud's imprint with anatomical features drawn from more than 100 human scans. "The nose might have come from here, the nostrils from there," he told me. The result is a realistic illustration, based on the data encoded in the shroud.

History Channel / Ray Downing

Illustrator Ray Downing tweaked graphic representations of human models to come up with a realistic 3-D image of the person whose imprint is on the Shroud of Turin.

Downing said the depiction shown in the History Channel program represents his best effort to put flesh and bones on the shroud's imprint - and he would argue that it's the best effort anyone has made. "This is the closest one, anatomically," he said.

Over the years, not everyone has agreed that the shroud can fit a realistic form. Joe Nickell, a paranormal investigator for Skeptical Inquirer magazine, told an interviewer a decade ago that if the draping effect is taken into account, the body beneath the shroud would have to have been "unusually narrow ... so very long and narrow that one pro-Shroud pathologist suggested that Jesus must have had Marfan's syndrome."

If Downing's analysis played it straight, the shape beneath the shroud is at least plausibly human. But is it Jesus? Or some anonymous person from the first or the 13th century? Feel free to weigh in with your comments below, before or after the show airs.

Update for 8:18 p.m. ET March 30: In a follow-up telephone interview, Skeptical Inquirer's Joe Nickell noted that questions have surrounded the Shroud of Turin since the 14th century, when it showed up in France. Nickell suggests that the shroud could have been forged by applying a red ochre pigment to the linen, then modeling it on a body with a bas-relief mask over the face.

Nickell said an Italian chemist, Luigi Garlaschelli, used the recipe to create a shroudlike replica. "He made a 'shroud' using the theories of mine that I told you, then artificially aged it by baking, and then he washed it to remove the pigment - and voila! There was the yellow stain," Nickell said. The effect was similar to the effect seen on the Shroud of Turin.

You can read more about Garlaschelli's experiment here and here.

"There are two approaches to this," Nickell told me. "There's ordinary science, and then there's what I call shroud science. Ordinary science starts with evidence, and lets the evidence lead wherever it will. This is the approach used by a 'CSI' team. Shroud science is quite different, and it starts with the answer. They start by saying, 'This is the shroud of our Lord,' and then they take whatever steps they need to get to that answer."

Nickell is skeptical ... not only about the Shroud of Turin, but also about the prospects for settling the shroud debate to everyone's satisfaction.

"Shroud science is backward from ordinary science," he said. "It's very discouraging to me that the media have been so willing to give it a pass."

Update for 2:50 p.m. ET March 31: I've been wading through thousands of comments on this item - an exercise that has revealed once again how fallible mortals (and software) can be. I apologize to those whose messages I have not approved, either because I just couldn't get to them or because they struck a slightly wrong or redundant chord. I also apologize to those who may take offense at some of the messages that were approved. Thanks to all of you who wrote in - and whether you're Christian or Jew, Muslim or Buddhist, of some other faith or of no religious faith at all, have an uplifting week! 

More on the Shroud of Turin:

• Could new test settle Shroud of Turin debate?
• Newsvine: What do you think of the Shroud?
• Big crowds expected to see the Shroud
• Gallery: The archaeology of Christianity
• Gallery: Are these artifacts fake or not?
• Gallery: The lighter side of religious sightings

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." 

NASA / JPL / GSFC / SwRI / SSI

The left image shows a visible-light image of Mimas, a Saturnian moon that has been nicknamed the Death Star because of its "Star Wars" look. The right image adds a false-color overlay of temperature data, which makes Mimas look more like "Pac-Man" in mid-munch. Click on the picture for a larger version.

The Cassini orbiter has gotten its closest look yet at Saturn's moon Mimas, which is nicknamed the "Death Star" because of its curious crater. The fresh imagery has generated new curiosities and yet another nickname for Mimas: the "Pac-Man" moon.

"After much deliberation, we have concluded: Mimas is not boring. Who knew?!" Cassini imaging team leader Carolyn Porco said in an e-mail announcing today's image release.

Linda Spilker, the Cassini project scientist at NASA's Jet Propulsion Laboratory, agreed: "Other moons usually grab the spotlight, but it turns out Mimas is more bizarre than we thought it was," she observed in an image advisory. "It has certainly given us some new puzzles."

The roughly 250-mile-wide (400-kilometer-wide) moon, whose name can be pronounced either like My-mass or Mee-muss, is already famous for a couple of features: First of all, its surface is dominated by an 88-mile-wide (140-kilometer-wide) pockmark known as Herschel Crater. That big circle makes the moon look eerily like the Death Star super-space station built by the evil Galactic Empire in the "Star Wars" saga.

Despite that impact crater, Mimas has kept its roundish shape - and that makes it the smallest astronomical object we know of that's round due to its self-gravity. It's less than a third as wide as Pluto, just to cite one example. If Mimas' principal orbit went around the sun rather than Saturn, it would be grouped along with Pluto as a dwarf planet. And that's led some astronomers to suggest that any worlds at least as massive as Mimas on the solar system's fringe should be considered dwarf planets - even if we can't see whether they're round.

NASA / JPL / SSI

A mosaic image shows the Saturnian moon Mimas, as seen during the Cassini probe's most recent flyby. Click on the image for a larger version.

Not so smooth
Being round doesn't necessarily mean you're smooth, and Mimas is a perfect example. The fresh imagery shows craters upon craters on the moon's predominantly icy surface. Some of the craters - and especially Herschel Crater - seem to have streaks and piles of darker stuff concentrated in valleys and at the base of crater walls.

The Cassini imaging team suspects that sunlight has been "baking" the ice for quite some time now, and as the ice evaporates out into space, darker impurities are left behind to pile up. Eventually those impurities fall to the bottom of the craters, creating avalanche streaks as they tumble down the walls. As the dark stuff falls, brighter ice is exposed on the walls themselves.

"These processes are not unique to Mimas," Cornell University's Paul Helfenstein, an imaging team associate, said in today's advisory, "but the new high-definition images are like Rosetta stones for interpreting them."

Cassini has been in Saturnian orbit since 2004, sending back thousands of pictures of the ringed planet and its moons. These latest high-definition images are based on data collected on Feb. 13, when the bus-sized probe came within about 5,900 miles (9,500 kilometers) of the moon. Today's findings come after weeks of data processing.

The Pac-Man moon
The findings took the form of surface temperature readings from Cassini's composite infrared spectrometer as well as pictures from Cassini's narrow-angle camera. The combination of those different types of data have given rise to a new puzzle ... and the "Pac-Man" nickname.

Because Mimas is mostly round, planetary scientists expected temperatures to vary evenly across the surface. Instead, they found a sharp boundary between warmer temperatures (around 294 degrees below zero Fahrenheit, or 92 Kelvin) and colder temperatures (-320 degrees F, or 77 K). A little warm spot (-310 degrees F, 84 K) was detected around Herschel Crater.

If you map the warmer temperatures in yellow and pink, and the colder temperatures in blue, you get a picture that looks exactly like the classic Pac-Man character eating a warm pinkish dot in Herschel Crater - as shown in the picture above.

The dot makes sense because Herschel's 3-mile-high (5-kilometer-high) walls can trap heat inside the crater. But scientists were baffled by the sharply defined, V-shaped pattern on the opposite side of Mimas' disk.

"We suspect the temperatures are revealing differences in texture on the surface," Southwest Research Institute's John Spencer, a member of the composite infrared spectrometer team, said in today's advisory. "It's maybe something like the difference between old, dense snow and freshly fallen powder."

Denser ice quickly conducts the heat of the sun away from the surface, keeping it cold during the day. Powdery ice is more insulating and traps the sun's heat at the surface, so the surface warms up.

	NASA / JPL / SSI
	A red-green stereo images shows the interior of Herschel Crater on Mimas. Click on the image for a larger version.

What could be behind the difference in texture? The fact that Herschel Crater is in the middle of all this suggests that Mimas' surface was dramatically altered by the impact that created the crater. The blast might have turned surface ice into water ... which was then flash-frozen as a dense top layer over the crater's surroundings.

But all the impacts that have occurred on Mimas since Herschel Crater was created should have pulverized that dense layer by now, Spencer said. So the mystery remains: Why are there such sharp differences on Mimas' surface, and why do they endure?

Chances are that Mimas' Death Star crater will play a big role in any explanation that astronomers come up with. To get a full sense of the crater's dramatic look, pull out your red-blue glasses and gaze at a 3-D stereo image of the hole, produced from bits and pieces of Cassini imagery. And to get a full sense of Mimas' roundness as compared with the non-roundness of some other moons, keep your glasses on and take a look at Prometheus and Phobos.

• New Scientist: What you need to know about car bugs
• ScienceNow: Could tiny bubbles cool the planet?
• SpaceWeather.com: Hear a radio-active sunspot
• Science News slideshow: Happy 20th, Hubble
• Bruceleeeowe's Blog: Carnival of Space 147

Like many other animals, hyenas can howl and grunt and growl. But what makes them giggle? Scientists studied a variety of hyena laughs to come up with the beginnings of an answer.

Imax / NASA

Click for Imax interactive: The movie "Hubble 3D" and similar efforts bridge the gap between cosmic sights and earthly audiences. Click on the image to see a Flash interactive model of the Hubble Space Telescope on the Imax Web site.

As the Hubble Space Telescope nears its 20th birthday, its value for research and the public understanding of science is reaching an unprecedented peak. Few celebrities have been the subject of so many biographies and movies by the time they turn 20.

The best of the bunch, in print and on the big screen, is arguably hitting the market right now, less than a year after a major upgrade left Hubble in the best shape it's ever been.

Hubble at the movies
"Hubble 3D," a monster-screen movie now playing at Imax theaters, combines amazing 3-D live footage of last May's final servicing mission with computer-generated zoom-through views of cosmic scenes.

The movie ranked No. 20 on the box-office list last weekend, grossing about $411,000 in just 39 theaters. We're not just talking here about No. 20 for movies that usually play at science centers and museums. We're talking about the big-time list: "Hubble 3D" nearly beat out "The Hurt Locker," which won the best-picture Oscar earlier this month. It made more money per screen than that other 3-D movie, the top-grossing "Alice in Wonderland."

It's not difficult to see why "Hubble 3D" is such a crowd-pleaser: The hardest-to-get shots were the 3-D panoramas showing the four-story-high telescope towering up from the shuttle Discovery's payload bay, with a fish-eye view of Earth's disk looming behind it. Last year, producer Toni Myers told me she could get only eight minutes' worth of film from that vantage point during each of the mission's five marathon spacewalks.

NASA

Astronaut Drew Feustel looms large as he moves a corrective-optics package from the Hubble Space Telescope to a stowage position during May's final servicing mission. This view was captured by the Imax 3-D camera in Atlantis' cargo bay.

During one of the panoramic scenes, astronaut Drew Feustel floats right across the screen, guiding a corrective-optics package to its storage slot. "You can see every stitch in his suit," Myers said. But I was too busy marveling over the zero-G, 3-D effect to count the stitches.

Some of the shots (including helmet-cam video views as well as archival film footage) were originally captured in 2-D and reprocessed to add 3-D perspective. The prime example of that is a scene documenting one of the mission's climactic moments, when spacewalker Mike Massimino pulls off a stuck handrail with his gloved hand.

You have to expect an ear-rattling shuttle launch when you go to an Imax movie with a space theme. "Hubble 3D" doubles your expectations by providing two: file footage of the liftoff on April 24, 1990, when Hubble was sent off into space; and a true 3-D view of last year's launch for the servicing mission.

It was an unexpected pleasure to see the astronauts at work and at leisure in 3-D, on Earth as well as in space. When "Hubble 3D" shows spacewalkers training in Johnson Space Center's practice pool, you feel as if you're right in the water with them. The funniest scene, at least during the showing I attended, came when Feustel fumbled with a tortilla spinning in zero-gravity and virtually dripping with what looked like chicken or tuna spread.

Hubble on the Web
If you liked the movie, you'll love the Web site: The "Hubble 3D" site offers video Webisodes, screensaver downloads, a picture-puzzle game and a virtual Hubble model that you can spin and click on for detailed information about the telescope. (We have our own virtual model that's not too shabby.)

Of course you'll want to check out the Hubble sites maintained by the Space Telescope Science Institute and the European Space Agency as well. And don't forget our own roundup of "Hubble's Latest, Greatest Hits," plus our audio slideshow featuring Hubble repairman Story Musgrave.

Hubble in print
If you love the Web sites but want to hold Hubble's wonders in your hands, there are plenty of books out there that chronicle Hubble's history and imagery. But the most up-to-date publication is "Hubble: A Journey Through Space and Time," a coffee-table book that recaps the final servicing mission and celebrates the telescope's 20th anniversary.

The 144-page volume is touted as "NASA's first book on the Hubble Space Telescope." The main text is written by Ed Weiler, who served as Hubble's chief scientist for almost 20 years (yes, since long before it was launched) and is now associate administrator for NASA's science mission directorate. Space agency chief Charles Bolden, who commanded the space shuttle mission for Hubble's deployment in 1990, contributes a foreword. (He also plays a cameo role in "Hubble 3-D.") Astronauts from each of the Hubble missions recap their contributions.

	Abrams
	"Hubble: A Journey Through Space and Time" tells the story of the space telescope and the people behind it.

Weiler succinctly retraces the story of Hubble's ups and downs - including the mirror flaw that turned Weiler's dream into a nightmare 20 years ago. "To me this compared to being on top of Mount Everest then tumbling down to Death Valley," he writes. Clever engineering compensated for the imperfection, however, and Hubble's triumph over adversity became a hallmark of the telescope's history.

Last year's servicing mission - which almost didn't happen, by the way - serves as the final chapter of the book. But the final chapter of Hubble's story is still far from being written. Thanks to the upgrades in its instruments, batteries and gyroscopes, the telescope is in peak condition and could keep working well into the decade ahead.

The James Webb Space Telescope, due for launch in 2014, may be portrayed as "Hubble's successor" - but it's hard to imagine anything taking Hubble's place in the hearts of its fans. Then again, who knows what the next generation of great observatories will find?

"After 20 years of phenomenal discoveries from Hubble and other space observatories, or view of the universe and our place within it has changed forever," Weiler writes. "These observations have taught us that there is still much to discover. I predict that we could very well, before the end of this century, prove definitively that there is life elsewhere."

Hubble and much, much more
While you're waiting for those answers to life's deepest questions, check out the views from Hubble and other probes in our Space Gallery. And in case you're looking for more information or downloadable images relating to our latest "Month in Space" slideshow, here are the Web links:

• Double-barreled blast, as seen by NASA's sun-watching STEREO mission.
• A strange land, photographed by NASA's Mars Reconnaissance Orbiter.
• Diving into a space job at Russia's Star City cosmonaut training complex.
• Winds of change in a galaxy watched by the Chandra X-Ray Observatory.
• Financial final frontier, starring Hubble repairmen at the New York Stock Exchange.
• Cosmic bat captured by the European Southern Observatory.
• Under construction: the NPP next-generation weather satellite at Ball Aerospace.
• Houston, we have a picture, thanks to the International Space Station's crew.
• Big ball of galactic fuzz, spotted by the Hubble Space Telescope.
• Storm in the East sends tons of sand sweeping across eastern China.
• SpaceShipTwo rising over California's Mojave Desert, attached to WhiteKnightTwo.
• She's ready to fly, aboard a Soyuz spacecraft bound for the space station.
• Blue Marble revisited, courtesy of the Goddard Photo and Video database on Flickr.
• Falcon fires its engines, marking another step for SpaceX's rocket ambitions.
• Red Planet ... in blue, as seen by Mars Reconnaissance Orbiter.
• Martian moon in 3-D, sent back by Europe's Mars Express orbiter.
• Packing up the shuttle, documented in NASA's Kennedy Space Center.
• Blooming with stars ... in a vast space cloud seen by NASA's WISE probe.
• Spring has sprung on Mars, and Mars Reconnaissance Orbiter sends back the proof.
• Touchdown! A Soyuz spacecraft brings space station astronauts back down to Earth.
• Lending a hand to astronaut Jeff Williams after the Soyuz landing.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on Monday.

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• Eruptions: Talking about science in the media
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• '1st Question': Watch yours truly lose a Second Life game show  

P. Simon (U. of Bonn) and T. Schrabback (Leiden Obs.) / NASA / ESA

This image shows a smoothed reconstruction of the total matter distribution in the COSMOS field based on telescope data. The color coding indicates the distance of the foreground mass concentrations, as inferred from gravitational lensing distortions. Structures shown in white, blue and green are typically closer to us than those indicated in orange and red. Click on the picture for a larger version.

A 3-D scan of hundreds of thousands of galaxies has confirmed the view that the expansion of the universe is speeding up, due to a mysterious factor called dark energy. The galaxy survey, described in a study set to be published by the journal Astronomy and Astrophysics, serves as one more line of evidence for dark energy's existence.

The idea behind dark energy cropped up 12 years ago when astronomers carefully measured how quickly supernovas were receding from us - and noticed that the speed was increasing with time. Since then, other types of evidence have piled up, including a survey of 13,000 galaxies conducted using the European Southern Observatory's Very Large Telescope in Chile.

The latest study kicks it up a notch by drawing upon the Hubble Space Telescope's COSMOS survey of more than 446,000 galaxies. Using ground-based telescopes, researchers were able to determine the distances to 194,000 of those galaxies - and chart the distribution of matter out to about 12 billion light-years.

Astronomers even accounted for the presence of dark matter in all those galaxies by analyzing how the gravitational effect of that unseen material warped the light coming from even more distant galaxies. This effect is called weak gravitational lensing.

A similar technique was used three years ago to generate a 3-D map of dark matter disribution from COSMOS data. Yet another gravitational-lensing study along the same lines was published in The Astrophysical Journal this year. The latest study puts together the 3-D map with information about how fast galaxies are receding, giving astronomers a better understanding of how the cosmic expansion has changed over time.

"The sheer number of galaxies included in this type of analysis is unprecedented, but more important is the wealth of information we could obtain about the invisible structures in the universe from this exceptional data set," one of the authors of the study, Patrick Simon of Edinburgh University, said in a news release issued by the European Space Agency's Hubble team.

When the researchers compared their data with different computer-generated models of what the universe should look like, they found that the models without dark energy could not fit what they were seeing.

"Dark energy affects our measurements for two reasons," said another co-author of the study, Benjamin Joachimi of the University of Bonn. "First, when it is present, galaxy clusters grow more slowly, and secondly, it changes the way the universe expands, leading to more distant - and more efficiently lensed - galaxies. Our analysis is sensitive to both effects."

Harvard astronomer William High said that most of the previous studies of matter distribution have been done in 2-D, like taking a chest X-ray of a patch of the night sky. "Our study is more like a 3-D reconstruction of the skeleton from a CT scan," he said. "On top of that, we are able to watch the skeleton of dark matter mature from the universe's youth to the present."

The European Hubble team released a color-coded image (in 2-D)  that charts the development of the cosmic skeleton. That's the image that appears at the top of this item. White, blue and green represent structures that are closer to us, while red and orange structures are farther away. In all these spots, dark matter accounts for most of the mass being mapped.

Such a breakdown is consistent with the current thinking that all the matter we can see accounts for only 4 percent of the universe's content, with dark matter making up 22 percent. The other 74 percent seems to be bound up in dark energy.

The Hubble study doesn't shed any new light on what dark matter or dark energy actually is. To determine the nature of dark matter, scientists will probably have to turn to the Large Hadron Collider or future astronomical observations.

And dark energy? Figuring out what that is poses an even bigger challenge. Scientists might just have to accept dark energy as a property of the universe where we happen to live, and add a cosmic "fudge factor" to the equations of general relativity. Or they might have to come up with something else entirely.

More on the dark universe:

• Interactive: Why does dark matter matter?
• Gallery: Dark matter revealed!
• Dark energy demystified

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on Monday.

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Mandel Ngan / AFP - Getty Images

Click for interactive: Skulls of early Homo sapiens (right) and a Neanderthal (left, in background) sit at the Smithsonian's National Museum of Natural History. Scientists say a third hominin group may have co-existed with those two groups 40,000 years ago. Click on the image to learn more about human evolution, in the past and perhaps in the future.

A DNA sample taken from an ancient pinky bone suggests that a previously unknown group of human ancestors mixed it up with Neanderthals and modern humans 40,000 years ago. Was it a completely different species? Too early to say, but it might depend on what your definition of "species" is.

The finding, published in this week's issue of the journal Nature, emerged from a check of DNA samples from Denisova Cave in southern Siberia's Altai Mountains. Anthropologists know that the cave was occupied by human ancestors off and on for at least 125,000 years, based on the artifacts and bits of bone found there.

The pinky bone was found in 2008, within a layer of material that has been dated to between 30,000 and 48,000 years ago. That's the precise time frame when both modern humans and Neanderthals inhabited the Altai Mountains. So when Johannes Krause of Germany's Max Planck Institute for Evolutionary Anthropology and his colleagues analyzed the mitochondrial DNA from the pinky bone, they expected the genetic code to match up with one species or the other.

Krause was surprised to discover that it didn't match either species. A colleague of his at the institute, Svante Pääbo, was even more surprised when Krause told him about it.

"At first I really didn't believe him," Pääbo, one of the world's top experts on ancient DNA analysis, told reporters during a teleconference. "I thought he was pulling my leg."

Riddles within riddles
The DNA posed an intriguing riddle: Mitochondrial DNA comes from the cellular energy factories outside the nucleus, and is passed down from a mother to her children. It can't provide the detailed genetic signature you can get from nuclear DNA. But it can serve as a "molecular clock" for evolutionary change, because it appears to mutate at a steady rate over time. Scientists can compare two different strings of mitochondrial coding to estimate when the two different organisms diverged on the evolutionary family tree.

The researchers ran the numbers for the pinky-bone sample, which they presume came from a young female nicknamed "X-Woman." They concluded that X-Woman's ancestors diverged from modern humans and Neanderthals about 1 million years ago. And that conclusion raised another riddle.

Based on previous research, anthropologists have thought that there were three great migrations of human ancestors out of Africa: The first came 1.9 million years ago, when Homo erectus headed toward Asia. The second came 300,000 to 500,000 years ago, when the ancestors of the Neanderthals trekked toward Europe and western Asia. The third occurred just 50,000 to 70,000 years ago, when anatomically modern humans headed out of Africa.

The fact that X-Woman's mitochondrial DNA was distinct from that of Neanderthals or modern humans would suggest that a third group of now-extinct human ancestors was still living in Siberia 40,000 years ago. Were they an offshoot from a completely different wave of migrants who left Africa after Homo erectus but before the ancestors of the Neanderthals? A different species entirely? The researchers are withholding judgment until they can sequence X-Woman's nuclear DNA. Pääbo said the results could be available "rather soon" but declined to give a precise timetable.

The species question is complicated because the various groups of human ancestors, known as hominins, might have interbred. That may go against one of the standard definitions of a species, as a group that can breed only amongst themselves. But evolutionary biologists are finding that nature doesn't necessarily obey our standard definitions. Neanderthals, for example, may have interbred with humans at some point. The same situation may apply to X-Woman.

"If it's just a modern human [that has] funny mitochondrial DNA, then you wouldn't call it a new species," Krause observed. Pääbo said he was "a bit skeptical about the fact that we can always have a clear species definition."

Migrants meeting migrants
Although they're cautious about the species question, Pääbo and Krause are confident that X-Woman represents a distinct group of migrants out of Africa. The "Hobbit" fossils found in Indonesia, which have been designated Homo floresiensis, apparently represent another. This is leading researchers to wonder whether human ancestors used the out-of-Africa route over and over again.

"Maybe it's an oversimplification to think about particular migrations out of Africa - saying there was one 2 million years ago, one half a million years ago, one 50,000 years ago. There might have been more or less continuous gene flow or migration that now and again is more frequent, less frequent," Pääbo said. "The picture that's going to emerge in the next years might be a more complex one."

In a commentary also published by Nature, the University of Manchester's Terence Brown said the mere fact that the research team was able to analyze 40,000-year-old DNA from X-Woman's pinky bone was an amazing achievement.

"The demonstration that a bone fragment can provide evidence for an unknown hominin will surely prompt more studies of this kind," he wrote, "and, possibly, increase the crowd of ancestors that early modern humans met when they traveled into Eurasia."

There may be more X-Women and X-Men out there, just waiting to be discovered. "After this amazing shock to find this, I would not be the one to say that one will not find new surprising things," Pääbo said.

Update for 2:45 p.m. ET March 25: There's quite a bit of buzz about all this among anthropologists - mostly on the question of whether or not X-Woman represents a new hominin species. ("Hominin" is currently the "in" term for humans and their extinct ancestors, and some would even classify chimps and bonobos as hominins as well. X-Woman is the nickname for the individual behind the pinky bone found in Siberia, even though the researchers don't yet know ... or at least haven't said ... whether that individual was female or male.)

A successful analysis of X-Woman's nuclear DNA would show how genetically distinct that creature was from modern humans and Neanderthals. If the genome is significantly different, that would strengthen the case for using a new species label. But the species identification would be something completely different from the usual routine, since it would be based on genetics alone.

Eventually, you'd want to link up the genetic identification with a morphological identification - that is, a set of bones that have a characteristic look to them. This would mean finding enough bones to identify, and then getting a DNA sequence that's sufficiently similar to X-Woman's. Only then could anyone say with confidence whether X-Woman belonged to some sort of Homo erectus offshoot, or a different species that we already know about (Heidelbergensis? Antecessor?), or a species that was previously unknown.

Anthropologists might eventually have to come up with a new way of identifying extinct hominin genomes, with a nomenclature that doesn't necessarily go by species names. For example, you could have Type 1 (Homo sapiens), Types 2 through 4 (Homo neanderthalensis), Type 5 (Homo floresiensis), Type 6 (X-Woman) and so on. In any case, it could take a long time to mesh the old, bone-based classification system with new genetic technologies.

Here are some additional perspectives on the X-Woman study:

• The Loom: The X-Woman's fingerbone
• John Hawks Weblog: The undiscovered hominin
• Times Online's Eureka Zone: Is X-Woman really a new species?
• Ars Technica: Neither Neanderthal nor sapiens
• Science News: Ancient DNA suggests new hominid line

More about DNA detective stories:

• Interactive: How DNA encodes our ancestry
• Three subgroups of Neanderthals identified
• DNA from ancient hair traces human history
• Human evolution kicks into high gear
• Ten fossils that tell the tale of our origins

The researchers behind the Nature study include Johannes Krause, Qiaomei Fu, Bence Viola and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany; Jeffrey M. Good of the University of Montana in Missoula; and Michael V. Shunkov and Anatoli P. Derevianko of the Russian Academy of Sciences, Siberian Branch.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on Monday.

• Wired: Is geoengineering 'a bad idea whose time has come'? 
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EMC2 Fusion Development Corp.

Plasma shines brightly inside EMC2 Fusion's WB-7 device, which was built to validate earlier experiments in inertial electrostatic confinement fusion.

There's more than one way to do fusion energy research: Some approaches rely on applying well-accepted physics, at a cost of billions of dollars, on a timeline that could stretch out for decades. Other approaches follow unconventional paths that could get to the goal much more quickly, for much less money ... but could also lead to dead ends.

Over the past couple of weeks, the folks following unconventional paths to fusion have signaled that they're a little surer about their progress - while some of the folks following the mainstream path are running into a little more trouble.

Does that mean low-budget fusion will prevail? Not necessarily. But it does mean that fusion research could heat up in the years to come.

Fusion power is so attractive because if it's done right, it could be so abundant. The aim is to bring the same principle that fuels the sun down to Earth: Crush atomic nuclei together to produce bigger nuclei (turning hydrogen to helium, for example), and in the process convert a tiny bit of mass into pure energy (in accordance with Einstein's E=mc² equation).

The mainstream timeline
The deuterium atoms in a gallon of seawater, for instance, could theoretically produce as much energy as burning 300 gallons of gasoline. The fuel contained in 50 cups of water could yield as much energy as burning two tons of coal. The problem is, how do you create a controlled reaction with enough temperature and pressure to get those nuclei fused together?

One way is to blast the fuel with precisely arranged laser beams: That's what the $3.5 billion National Ignition Facility is aiming to do starting later this year, in hopes of creating the first-ever controlled reaction that puts out more energy than it takes in. Last month, Edward Moses, NIF's principal associate director, said it may take a year or two to reach that "scientific break-even" point (as opposed to commercial break-even, which would take more than a decade).

Another way is to heat up a plasma inside a magnetic containment vessel - and then feed it fusion fuel to keep the blast going. That's what the international ITER project is aiming to do at an experimental facility now taking shape in France. However, ITER has been experiencing schedule slips and money problems for the past couple of years.

This month, the director of the U.S. Department of Energy's Office of Science, William Brinkman, reportedly told an advisory panel that ITER was due for a shakeup. "If I could get my hands on the person who proposed the current management structure, I would strangle him," he was quoted as saying.

The current timeline calls for the demonstration reactor to start up in late 2019, with full-scale experiments starting in 2026. But those dates could well slip again, and costs seem likely to escalate. (The most widely used ballpark figure in current usage is 10 billion euros, or $13 billion.)

The alternate timeline
You won't hear Rick Nebel talking about fusion as a challenge requiring billions of dollars and decades of experimentation. For the past couple of years, Nebel heads up a handful of researchers following the less-traveled path to fusion at EMC2 Fusion Development Corp. in Santa Fe, N.M. That path involves creating a high-voltage chamber to sling ions so energetically at each other that at least some of them fuse and release energy.

EMC2 recently created a buzz in the fusion underground by reporting on its Web site that it successfully completed a series of experiments to "validate and extend" earlier results reported by the late physicist Robert Bussard. The company is now using a $7.9 million contract from the U.S. Navy to build a bigger test machine, known as WB-8. (WB stands for "Wiffle Ball," which refers to the shape of the machine's magnetic fields.)

What's more, Nebel and his colleagues are now seeking contributions to fund the development of what they say would be a 100-megawatt fusion plant - a "Phase 3" effort projected to cost $200 million and take four years.

"Successful Phase 3 marks the end of fossil fuels," the Web site proclaims.

Reality check
Success isn't assured. The WB-8 experiment could conceivably show that the approach pioneered by Bussard, known as inertial electrostatic confinement fusion or IEC fusion, can't be scaled up to produce more power than it consumes. And if Nebel's team comes to that conclusion, he doesn't plan to pull any punches.

"No B.S. and no excuses," Nebel told me over the weekend. "If it looks like we have a problem with this, we're going to tell them."

But if IEC fusion actually works, Nebel wants to be ready to commercialize the technology. "Generally what you want to do is have one machine operating, one machine being built, and one machine designed," he said. "We want to be in a position that if we have good results from WB-8, we can hit the ground running."

That's what the contributions being sought under the umbrella of the New Mexico Community Foundation would go toward, he said. Nebel doesn't expect anything near $200 million to start with. "We're just looking for a few hundred thousand to do the design work and do some basic physics on this," he said. "There are some open questions we have to take a look at."

The EMC2 Fusion Web site sports a picture of a 100-megawatt WB-D fusion demonstrator, which looks like a cube about 20 feet on a side. Nebel said the eventual design may not look like the picture, but he does believe the best path to success leads to relatively small-scale reactors rather than the mega-reactors envisioned by ITER's backers.

"The key to making any of these things attractive is being able to make them small," he said.

Nebel can't yet predict whether his path will pan out. Some experts say the equations of plasma physics suggest that Wiffle Ball devices can never produce more power than it consumes, and that IEC research is destined to lead to a dead end. But so far, Nebel sees no reason to stop moving ahead. "It's been quite a trip on this thing," he said, "and I have a feeling this is going to continue."

Other paths less-traveled
Unorthodox paths to fusion have been getting more than their usual share of exposure lately. Several private ventures are searching for shortcuts to commercial power production, and one of them, General Fusion, is profiled this month in hPlus magazine. The Canadian company is working on an approach known as magnetized target fusion, which combines elements of inertial confinement (like the National Ignition Facility) and magnetic confinement (like ITER).

One of General Fusion's prime targets is raising the $50 million (Canadian) it says it needs to build a commercial reactor. So far, the Canadian government has kicked in $13.9 million, and venture capitalists including Chrysalix Energy Ventures have invested another $9 million.

In the hPlus article, General Fusion CEO Doug Richardson says his company's research path is not all that unorthodox. "We're boring," he says. "This is basic stuff, and all we're doing is taking other people's ideas and going down a path that no one has taken yet."

This week, scientists gathered at the American Chemical Society's spring meeting in San Francisco to turn the spotlight on a highly unorthodox path: the effect known as cold fusion.

Back in 1989, cold fusion was heralded as a simple, inexpensive way to get a power-generating fusion reaction on a desktop. But when the experimental results couldn't be reproduced, the researchers were driven into obscurity.

For many physicists, the term "cold fusion" became synonymous with quackery. Chemists, however, have kept up their interest in the effect. This isn't the first time the ACS has hosted a symposium on cold fusion. But the subject's popularity seems to be rising: This year's session featured nearly 50 presentations - including reports on batteries and bacteria that appear to exhibit the cold-fusion effect.

"There's still some resistance to this field," symposium organizer Jan Marwan, of Berlin-based Marwan Chemie, said in a news release. "But we just have to keep on as we have done so far, exploring cold fusion step by step, and that will make it a successful alternative energy source."

Nature's Katharine Sanderson paid a visit to the ACS's cold-fusion news conference - and came away saying she was "still not convinced" that the effect could truly be termed fusion. For that reason, some in the field now prefer the term "low-energy nuclear reactions." New Energy Times' Steven Krivit, who co-wrote a book titled "The Rebirth of Cold Fusion" in 2004, thinks the effect has something to do with weak nuclear interactions but now says "it's not fusion."

Whatever it is, scientists will eventually have to show conclusively that the effect produces more energy than it consumes in order for the wider world to take it seriously as a power source. Come to think of it, that requirement applies to all the paths to fusion ... conventional as well as unconventional.

What do you think? How much time and money should be spent on fusion research here on Earth, especially when you consider there's a perfectly fine fusion source 93 million miles away? Join the discussion by leaving your comment below.

More on the fusion quest:

• Roundup: Will fusion fade ... or finally flare up?
• Talk-Polywell.org: Discussion forum for IEC fusion
• IEC Fusion Technology: M. Simon's Weblog on the subject
• Next Big Future: Look for the IEC fusion tags
• Fusor.net: Open Source Fusor Research Consortium
• Why China wants to go to the moon: He-3 as fusion fuel

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on Monday.

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Mark Greenberg / Virgin Galactic

The SpaceShipTwo rocket plane is attached between the twin fuselages of its WhiteKnightTwo carrier airplane, as seen from below during Monday's test flight from California's Mojave Air and Space Port.

Virgin Galactic's SpaceShipTwo rocket plane took to the air for the first time this morning from California's Mojave Air and Space Port.

The craft, which has been christened the VSS Enterprise, remained firmly attached to its WhiteKnightTwo carrier airplane throughout the nearly three-hour test flight. It will take many months of further tests before SpaceShipTwo actually goes into outer space. Nevertheless, today's outing marks an important milestone along a path that could take paying passengers to the final frontier as early as 2011 or 2012.

The captive-carry flight comes three and a half months after SpaceShipTwo's unveiling in Mojave. The project, backed by British billionaire Richard Branson, builds upon the first-ever private-sector spaceflights, flown five years ago by the SpaceShipOne prototype plane. Both SpaceShipOne and SpaceShipTwo were designed by aerospace guru Burt Rutan, founder of Mojave-based Scaled Composites.

Today's test, piloted by Scaled Composites' Mark Stucky, was the first in a series aimed at checking the aerodynamics of the rocket plane in a controlled, real-world environment. The configuration for SpaceShipTwo is significantly different from that for SpaceShipOne (which is now hanging in the Smithsonian's National Air and Space Museum) and its WhiteKnightOne mothership. SpaceShipOne was slung right beneath WhiteKnightOne's fuselage, while SpaceShipTwo rides between WhiteKnightTwo's twin fuselages.

Virgin Galactic's spaceflight profile calls for the rocket to be taken up to around 50,000 feet in altitude, where it would be released from the mothership. SpaceShipTwo would then fire up its own rocket engine for the final push to space. But for these initial captive-carry tests, the rocket plane will stay attached to WhiteKnightTwo.

Mark Greenberg / Virgin Galactic

Virgin Galactic's SpaceShipTwo rocket plane takes to the air for a test flight on Monday, firmly connected to its WhiteKnightTwo carrier airplane.

When Rutan and his team are confident that they've tweaked the design to optimize its flightworthiness, they'll move on to the next phase of testing: unpowered glide tests, during which WhiteKnightTwo will release SpaceShipTwo (and its pilot) for a gliding flight back down to the Mojave runway.

That phase will lead to an even more ambitious series of flights, scheduled to start next year, during which SpaceShipTwo will light up its hybrid rocket engine. Eventually those powered test flights will push the plane beyond the sound barrier - and beyond the 100-kilometer (62-mile) altitude mark that serves as the internationally accepted boundary of outer space.

Passenger operations won't begin until a goodly number of test flights have broken the space barrier. No firm date has been set, but the conventional wisdom is currently focusing on late 2011 or early 2012. "Test flights will pace the program," Virgin Galactic's operations manager, Julie Tizard, said last year at a spaceflight conference in New Mexico.

Virgin Galactic's test program is being conducted out of Mojave, where Rutan's Scaled Composites has its home base. However, the passenger flights will likely be run out of New Mexico's Spaceport America, which is currently under construction.

Executives at Virgin Galactic have consistently said no paying passengers will be taken on until they're confident that the flights measure up to their safety standards. Branson and his family are to be among the first spacefliers.

More than 330 people have already put down deposits toward the $200,000 fare for a tour package - an adventure that will feature a rocket-powered roller-coaster ride, several minutes of weightlessness, and a commanding view of the curving Earth beneath the blackness of space.

Mark Greenberg / Virgin Galactic

An in-flight closeup shows SpaceShipTwo riding between WhiteKnightTwo's twin  fuselages. This SpaceShipTwo plane has been christened the Enterprise, and the WhiteKnightTwo is named Eve, after Virgin founder Richard Branson's mother. Click on the picture for a larger view that clearly shows the "Eve" mascots.

Here's the full news release from Virgin Galactic, with quotes from Rutan and Branson:

"Virgin Galactic announced today that its commercial manned spaceship, VSS Enterprise, this morning successfully completed its first 'captive carry' test flight, taking off at 07:05 am (PST) from Mojave Air and Spaceport, California.

"The spaceship was unveiled to the public for the first time on December 7th 2009 and named by Governors [Arnold] Schwarzenegger [of California] and [New Mexico's Bill] Richardson. VSS Enterprise remained attached to its unique WhiteKnightTwo carrier aircraft, VMS Eve, for the duration of the 2 hours 54 minutes flight, achieving an altitude of 45,000 feet (13716 meters).
 
"Both vehicles are being developed for Sir Richard Branson's Virgin Galactic, by Mojave based Scaled Composites. Founded by Burt Rutan, Scaled developed SpaceShipOne which in 2004 claimed the $10 million Ansari X Prize as the world's first privately developed manned spacecraft. Virgin Galactic's new vehicles share much of the same basic design but are being built to carry six fare-paying passengers on suborbital space flights, allowing an out-of-the-seat zero gravity experience and offering astounding views of the planet from the black sky of space.

"Virgin Galactic has already taken around $45 million in deposits for spaceflight reservations from over 330 people wanting to experience space for themselves.

"The first flight of VSS Enterprise is another major milestone in an exhaustive flight testing program, which started with the inaugural flight of VMS Eve in 2008 and is at the heart of Virgin Galactic's commitment to safety.

"Commenting on the historic flight, Burt Rutan said: 'This is a momentous day for the Scaled and Virgin Teams. The captive-carry flight signifies the start of what we believe will be extremely exciting and successful spaceship flight test program.'

"Sir Richard Branson, founder of Virgin Galactic, added: 'Seeing the finished spaceship in December was a major day for us, but watching VSS Enterprise fly for the first time really brings home what beautiful, ground-breaking vehicles Burt and his team have developed for us. It comes as no surprise that the flight went so well; the Scaled team is uniquely qualified to bring this important and incredible dream to reality. Today was another major step along that road and a testament to US engineering and innovation.'

"The VSS Enterprise test flight program will continue though 2010 and 2011, progressing from captive carry to independent glide and then powered flight, prior to the start of commercial operations."

Virgin Galactic's business plan calls for building five SpaceShipTwo planes and two WhiteKnightTwo carriers, with options for more.

More about SpaceShipTwo:

• YouTube: Watch SpaceShipTwo's first flight  
• Video: 'Nightly News' traces effort's past, present and future
• Slideshow: Scenes from the making of SpaceShipTwo
• Interactive: How SpaceShipOne works 
• More pictures from Virgin Galactic's Flickr album

This report was last updated at 2:45 p.m. ET March 23.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on March 29.

	JAXA
	An artist's rendering shows Japan's Ikaros solar sail in flight.

As Japan gears up to send the first working solar sail into deep space in a couple of months, the Planetary Society is moving ahead with its own solar-sail project. You can put your name on both sails … if you act now.

Sunday is the deadline for adding your name to the list for Japan's Ikaros spacecraft, due to piggyback on the May 18 launch of the Venus-bound Akatsuki orbiter aboard a Japanese H-2A rocket. More than 25,000 people have signed up already using the Planetary Society's "Sail Away" Web page - and when those are added to the Japanese list, the tally goes up to 60,000 names.

All those names will be digitally encoded on the same kind of silica glass mini-DVD that was sent to the Red Planet on the Phoenix Mars Lander as well as on each of NASA's Mars rovers, said Bruce Betts, director of projects for the Planetary Society. The California-based society is a space advocacy group co-founded by the late astronomer Carl Sagan.

If you sign up now, you can get a two-fer: The list of names will also be encoded on a mini-DVD accompanying the Planetary Society's LightSail-1. And even if you miss out this weekend, you can still make it onto that later flight.

How much later? When the $1 million-plus LightSail mission was announced last November, its backers hoped to get it off the ground sometime this year. But the Planetary Society's executive director, Louis Friedman, told me today that schedule would have to be stretched.

"We can still be ready by the end of 2010, but the launch vehicle will probably not be available until the first part of 2011," he said.

In fact, LightSail-1's launch vehicle has not yet been selected. The Planetary Society is planning to piggyback on someone else's liftoff - perhaps on a defense-related flight, or a commercial launch, or a mission launched from outside the United States.

"The good news is, we have many options. The bad news is, we have many options," Friedman joked.

One option that's not on the table is Russia's sub-launched Volna rocket. In 2005, a Volna launched the Planetary Society's previous solar-sail prototype, Cosmos 1, but a premature shutdown of the rocket's first stage led to mission failure.

LightSail-1 and Ikaros are both aimed at showing that solar sails can actually propel a spacecraft through the cosmos - something that's never been done before, even though people have tried for more than a decade. Russian solar sail missions failed in 1999 and 2001. The Japanese successfully tested the deployment of a solar sail in 2004, but that suborbital experiment did not address the propulsion question. A NASA experiment known as NanoSail-D went awry in 2008 when its SpaceX Falcon 1 launch vehicle failed to reach orbit.

The idea behind solar sailing is that photons of light bounce off the sail's surface, exerting enough pressure over a wide surface to give a push to the spacecraft. That push is gentle, but over time, the steady acceleration from sunlight could eventually send the sail on an interstellar cruise.

All about Ikaros
The 700-pound (315-kilogram) Ikaros spacecraft's name refers to the classic Greek myth of Icarus, the youth who made wings from feathers and wax but flew too close to the sun. It's also an acronym, standing for "Interplanetary Kite-craft Accelerated by Radiation Of the Sun."

Its objective is not to fly to the sun or to the stars, but merely to show that a sailcraft can be propelled and steered through deep space. Ikaros is launched with its sail rolled up in a flat cylinder. After separation from the launch vehicle, the probe would spin itself at a rate of up to 20 revolutions per minute to unfurl the squarish sail.

When fully deployed, the thin-film sail would stretch 66 feet (20 meters) along its diagonal. Tiny solar cells, dust counters and reflective steering devices are mounted as panels on the sail.

Betts said Ikaros' flight plan is "ideal for solar sailing," because the sail would be unfurled beyond Earth orbit. "It's like sailing in the open ocean as opposed to sailing in the harbor," he explained. "You don't have to keep tacking or changing the orientation of your sail."

Japanese researchers see Ikaros' flight as the first in a series of solar-powered space odysseys, leading up to a mission heading for Jupiter and its retinue of Trojan asteroids sometime in the 2020s. That ambitious journey calls for the use of a solar sail as well as a solar-electric ion engine.

All about LightSail-1
The Planetary Society also sees its LightSail mission as the first of a set. A chart for the mission program suggests that mission planners are working toward a flight in 2015 that would boost LightSail-3 beyond Earth orbit to the L1 gravitational balance point between Earth and the sun. That's about 1 million miles (1.5 million kilometers) away.

Rick Sternbach / Planetary Society

The LightSail-1 craft consists of three CubeSats at the center of four lightweight triangular sails.

LightSail-1 consists of three linked-together microsatellites, or CubeSats, each 4 inches (10 centimeters) on a side. One CubeSat contains the electronics and control module, while the other two contain the folded-up plastic panels for the solar sail. Total weight is projected to be less than 11 pounds (5 kilograms).

When fully unfurled, the sail would have an area of 344 square feet (32 square meters). That works out to about 18.5 feet (5.7 meters) on a side. The craft would look like a giant, silvery kite in orbit.

Although the spacecraft has about as much volume as an express-mail package, Friedman said there's more than enough space for what the Planetary Society wants to do.

"It's so much more interesting than I first realized, even when we started down the path of building these CubeSats," he said. "These 4-inch spacecraft are the wave of the future. ... You can do so much on these spacecraft."

A mini-camera would be built into the package to send back imagery of the sail deployment after its launch on the yet-to-be-named rocket, Friedman said. "We'll be involving people from the public for optical and maybe even ham-radio tracking," he said. The key question would be whether the pressure of sunlight is enough to boost the sail to a higher orbit. 

It all sounds pretty cool ... as long as someone comes up with the right rocket. That's more complicated than you might think, because engineers have calculated that LightSail-1 has to be deployed in an orbit at least 500 miles high (800 kilometers). Otherwise, any propulsive effect from sunlight would be canceled out by atmospheric drag.

"Above 850 kilometers, you're clearly getting the dominant effect of the solar pressure," Betts explained. To achieve that altitude, LightSail-1 would have to piggyback on a launch going beyond low Earth orbit. There aren't that many rockets going that far out with payload capacity to spare, but the folks at the Planetary Society are confident they'll strike a deal with someone in the months ahead.

Friedman said Ikaros' planners were lucky to have a Venus mission they could latch onto. "I'm envious that they can get this ride out to interplanetary space," he said.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on March 29.

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Science / AAAS

This graphic shows a 3-D nanostructure, consisting of a bumpy gold surface layer with the tailored "invisibility cloak" underneath. The cloak, made from laser-sculpted layers of polymer, hides the bump from optical detection.

Scientists have designed a more stylish cloak of invisibility that can hide a bumpy feature from view, even if you're looking right at it from a wide range of perspectives. But don't expect boy wizard Harry Potter to be modeling this cloak anytime soon.

It's actually more like an ultra-thin carpet of invisibility, created from layers of laser-sculpted polymer and topped off with a bumpy coating of gold.

"In our carpet, you could put any object beneath the bump, and it would be hidden because the bump itself is hidden," Tolga Ergin, a physicist at Germany's Karlsruhe Institute of Technology, told me. The research conducted by Ergin and his colleagues was published online today by the journal Science.

Invisibility cloaks have long been a feature of fictional sagas including the Harry Potter book series and the "Star Trek" TV shows and films. As usual, fabricating such cloaks is harder to do in reality than it is in fiction. The challenge involves creating metamaterials that guide light waves on a detour around an object, instead of letting them hit the object and bounce back to the observer.

The first cloaks worked only in a two-dimensional plane, but last year researchers at Rice University unveiled a metamaterial that could produce a 3-D cloaking effect. The newly published German experiment could be considered the first 3-D demonstration of an invisibility carpet.

To create the carpet, the researchers laid down layers of polymer on a glass foundation, using a laser to sculpt each layer into a pattern of rods. This process is known as direct laser writing or 3-D laser lithography. The layers of rods were stacked on top of each other to produce a "woodpile" with a dent running down the middle. Then a thin reflective surface of gold was layered on top.

The resulting material, shown in the graphic above, is thinner than the width of a human hair with a depression that measured just one micron (a millionth of a meter) deep. The woodpile of rods is carefully structured so that light is refracted along complex paths that dodge the dented area. When scientists shone infrared light up through the woodpile, they could see the reflective gold surface. But the dent, which was a bump when seen from below, could not be detected. Instead, it looked as if the gold surface was perfectly smooth.

The invisibility effect wasn't restricted to just one viewing angle. "We saw that it worked quite well even to large angles," Ergin said.

The carpet had several limitations, however. "This is a great step they've made," said David Schurig, a physicist at North Carolina State University who helped create the first working 2-D invisibility cloak. "But there are a lot more steps to get to what you and most people imagine when you think of cloaking devices."

For example, the woodpile material works only down to the near-infrared part of the electromagnetic spectrum, around wavelengths of 1.2 microns. As the light came closer to the visible spectrum, scientists started seeing the pattern of rods instead of the gold surface beyond. In Harry Potter terms, the cloak itself became visible. "You start to see that there is something on top of this bump," Ergin said.

The size of the hidden region is also incredibly tiny - far too small for Harry to fit inside, even if he used a spell to shrink himself to the size of an ant. Making an invisibility carpet to cover larger objects would take much more time and effort.

Schurig also would like to see a device that routes light waves all the way around a hidden object, so that it truly looks as if there is nothing to see at all. "It'd be nice to hide things in free space, as opposed to beneath a surface, and it'd be nice to do it broadband in the visible spectrum," Schuring said.

Ergin acknowledged that his research group's invisibility carpet wouldn't do Harry much good. "Of course it is not a 'good' invisibility device, but it is one that is experimentally feasible, and it is a beautiful benchmark for showing these concepts for transformation optics.," he said.

The U.S. military has funded some research into cloaking technologies, including acoustic cloaks that could make submarines "invisible" to sonar, but Ergin emphasized that his work is going in a different direction. "This has absolutely nothing to do with going to military research and hiding tanks and soldiers," he told me.

Instead, he and his colleagues are focusing on exotic ways to twist and turn light waves using metamaterials. Such research could open the way for the development of super-fast optical circuitry. Another oft-mentioned application is the invention of super-antennas that could collect light from a range of directions and direct it to a single point. Metamaterials could also be used to simulate relativistic effects - for example, in optical black holes.

Wizards may not be modeling invisibility cloaks anytime soon, but you can expect research into cloaking effects to produce some real-life wizardry in the years ahead. Just don't ask Ergin to predict precisely what form those scientific spells will take.

"I can't really tell you what people might bring up in the next 10 years," he told me. "If I had 10 good ideas, I would have published them already."

Authors of the Science research on the three-dimensional invisibility cloak include Tolga Ergin, Nicolas Stenger, Patrice Brenner and Martin Wegener of the Karlsruhe Institute of Technology, as well as John B. Pendry of Imperial College London.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on March 29.

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	msnbc.com
	Click for interactive: Learn more about quantum mechanics and its application to computing.

The quantum world may seem so small and weird that there's no connection with everyday reality, but that impression couldn't be further from the truth. Newly published studies - and a newly released documentary - explore the big frontiers of the quantum information revolution.

Actually, quantum physics is as connected to everyday reality as the device that's displaying these words of mine. If it weren't for the quantum nature of light, inventions such as computers, TVs and DVD players would be impossible.

Some aspects of quantum mechanics are easier to understand than others, however. It's one thing to wrap your mind around the idea that light comes in individual packets called photons, and quite another to suggest that a single photon can travel along two paths at once. Or to suggest that two photons can be linked so strongly that doing something to one of them affects the other. Even Albert Einstein said that was "spooky."

It may be that our brains just aren't programmed to pick up on the weirder implications of quantum physics, such as superposition, information teleportation and particle entanglement. But Anton Zeilinger, a University of Vienna physicist who pioneered the technology behind teleportation, says that doesn't always have to be the case.

"I'm dreaming of teaching small children, maybe 4-year-olds, about quantum phenomena," he told me this week. "You can't teach them the math, that's quite clear. But you can show them apparatuses or simulate this behavior in a quantum way, just to see what they make out of it. Maybe if you get exposed early, you have a better intuitive grasp."

With repeated exposure, students get the idea that quantum information isn't that spooky after all, said Ray Laflamme, director of the Institute for Quantum Computing at the University of Waterloo in Ontario. He compared the current age to the 19th century, when the famed physicist Lord Kelvin declared that "heavier-than-air flying machines are impossible."

"We don't have the technology ... to build the intuition," Laflamme told me. He said it would be up to the next generation to absorb quantum concepts "so that it becomes second nature - just as when you get on a plane, you don't think, 'Is this thing really going to fly?'"

Quantum devices: Ready for takeoff?
One of the concepts that's just beginning to take off is the idea that it should be possible to extend the quantum world from the realm of the super-small  to a scale large enough to allow for the construction of actual devices for information processing.

A paper published in Thursday's issue of Nature takes a big leap in that direction by describing the creation of a quantum information device big enough to be seen with the naked eye. The device, which looks like a computer chip, links together a superconducting quantum-bit circuit with a tiny mechanical resonator capable of vibrating nearly 6 billion times a second.

The device was chilled down to a temperature of 25 millikelvin, or roughly 0.05 degrees Fahrenheit above absolute zero. Andrew Cleland, a physicist at the University of California at Santa Barbara who was on the research team, explained that the chip had to get that cold to cut down on the noise of vibrating atoms. "Everything on your desk is vibrating ever so slightly because it's at a non-zero temperature," he told me.

	O'Connell et al. / Nature
	This optical micrograph shows a mechanical resonator connected to a quantum-bit circuit on a chip. The resonator, at the bottom of the chip, is about 60 microns wide, or about the width of a human hair.

Twenty-five millikelvin is pretty cold - colder than the chilliest corners of outer space, in fact - but if the resonator weren't vibrating so rapidly, it'd have to get even colder. A typical tuning fork, for example, would have to be chilled down to less than a millionth of a degree above absolute zero to exhibit quantum properties.

The quantum-bit circuit could be used to measure the quantum state of the resonator, or create a single excitation in the resonator. The results demonstrated that a device containing trillions of atoms could do the same quantum tricks usually seen only on the scale of dozens of atoms.

"We were just trying to demonstrate quantum effects in a big thing," Cleland said. "But a possible application would be if you try to detect these acoustic vibrations at the quantum level. You could do it with this. You could use it as a quantum microphone, or a quantum loudspeaker."

In a commentary also published by Nature, University of Vienna physicist Markus Aspelmeyer said Cleland and his colleagues "have taken a decisive first step towards an exciting future in mechanical quantum physics." Resonators like the one described in the Nature paper could conceivably be used as sensors for quantum effects, or memory devices for quantum computers, or interfaces to read out the results of a quantum calculation.

Yet another paper in Nature describes the combination of super-cooled gas and a single trapped ion to create a different type of hybrid quantum system that could find its way into future computing systems.

The federal government has long been interested in quantum computing: The Pentagon's Defense Advanced Research Projects Agency has a multimillion-dollar program for quantum entanglement science and technology, and the National Science Foundation recently awarded a $900,000 grant to support the development of quantum computer hardware.

Reality check for quantum computers
I wrote my first story about the promise of quantum computing almost 10 years ago - and at the time, some physicists were saying that a computer capable of manipulating 30 bits of quantum information, or qubits, just might be developed by ... um, 2010.

Back in the real world, researchers proudly announced last year that they had created a two-qubit chip, and Laflamme said today's experiments can deal with only 10 qubits or so. "You wouldn't go very far on the stock market if you had just 10 quantum bits, but for the science and technology of quantum information, it's critical," he said.

A couple of years ago, Canada's D-Wave Systems claimed that it successfully incorporated quantum-mechanical principles in one of its computer models, but backed away from suggestions that it had built a general-purpose quantum computer.

"Maybe a few people might have been foolish enough to expect quantum computers in 10 years, but it could be 50 years before we get quantum computers," Laflamme said. "For people working in the field, quantum computers are the holy grail. ... On the way there, there are the side effects: quantum communication and cryptography, the sensors that people are building."

As I explained back in 2000, quantum information processing could be used to crack the secret codes that currently protect confidential information on the Internet. But quantum technology is also well-suited for a new kind of encryption that would instantly detect the presence of eavesdroppers.

"It offers ways of returning to ideas of privacy," said David Cory, a nuclear engineering professor at the Massachusetts Institute of Technology who specializes in spin-based quantum information processing. "There are a lot of appealing ideas to the power of quantum cryptography and quantum communication."

Taming quantum physics
Cory acknowledged that non-scientists can have a hard time with some concepts in the quantum world - for example, the idea that something can be "on" and "off" at the same time. The thought experiment known as "Schrödinger's Cat," in which a cooped-up kitty is considered simultaneously dead and alive, is a classic example of the weirdness surrounding quantum superposition. But Cory also thinks the weirdness is oversold.

"It makes me cringe when I hear people say how weird quantum mechanics is, when we understand it so well," he told me. "The first lesson is that you shouldn't suggest it's so weird. It is wonderfully predictable. You really can do the engineering right."

"And it's a mathematically beautiful field," Zeilinger added. "It's mind-boggling how beautiful it is. Unfortunately, you have to know mathematics to see that. But it's really beautiful."

Zeilinger, Cory and Laflamme all contribute to reducing the weirdness quotient in "The Quantum Tamers," a new video documentary created by Canada's Perimeter Institute for Theoretical Physics. The 52-minute program features easily digestible talks about quantum physics by 19 big-name scientists, with Stephen Hawking as the headliner. You'll also see eye-pleasing demonstrations of superposition, entanglement and teleportation, performed by actors and dancers who stand in for the quantum bits.

O'Connell et al. / Nature

University of Waterloo quantum physicist Ray Laflamme explains superposition with the aid of a four-armed bearer of ones and zeroes in "The Quantum Tamers."

The show has been scheduled for airing in television markets around the world, but not yet in the United States. DVDs are available for institutional use, but not yet for the home-video market (unless you're up for paying $169.95 plus shipping and tax). I suspect that it's only a matter of time before "The Quantum Tamers" shows up on a TV set near you. In the meantime, you can watch a series of clips from the documentary online.

Laflamme said working on the show was loads of fun - and loads of work. "I seem to set myself up for things that take more time than I thought," he told me. But the way Laflamme sees it, getting out the message about quantum physics is as important as actually doing quantum physics.

"I eat, sleep and think about this all the time," he told me. "I love to try to extract the important pieces of it, and try to explain it. I'm one of those who believes that these technologies will have a profound impact on society. My bet is that it will be the same as the information technologies that we've seen in the past 50 years. ... It will dramatically change the way we think about and perceive the world. It might take 50 or 100 years, but it will happen."

Update for 6:15 p.m. ET March 18: Veteran science writer Charlie Petit, the guru behind the Knight Science Journalism Tracker, offers up the full text of the commentary written by Aspelmeyer. "He could have made a living as a journalist - but may be having as much fun in physics already," Petit says.

Authors of the Nature research on the mechanical resonator include A.D. O'Connell, M. Hofheinz, M. Ansmann, Radoslaw C. Bialczak, M. Lenander, Erik Lucero, M. Neeley, D. Sank, H. Wang, M. Weides, J. Wenner, John M. Martinis and A.N. Cleland, all of the University of California at Santa Barbara. The researchers for the paper on the hybrid quantum system are Christoph Zipkes, Stefan Palzer, Carlo Sias and Michael Köhl, all of the University of Cambridge's Cavendish Laboratory.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a "Science on Tap" talk in Seattle on March 29.

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L. Fletcher / ESO / NASA / JPL / ESA

The thermal image at left charts temperature variations in three storms on Jupiter — the Great Red Spot, Oval BA and Baby Red. The Hubble Space Telescope image at right shows the same scene in visible light. Both images were captured in May 2008. Click on the picture to see a larger version.

Thermal images have charted the temperature of Jupiter's Great Red Spot in unprecedented detail, revealing that the very center of the spot is warmer than the outer edges. The readings reveal the meteorological mechanics behind the solar system's strongest storm.

"We once thought that the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated," Glenn Orton, a researcher at NASA's Jet Propulsion Laboratory who headed up the research team behind the temperature study, said today in an image advisory from the European Southern Observatory.

The Great Red Spot, which is so wide three Earths could be lined up side by side across its breadth, has existed for hundreds of years. It's the "most often-observed feature in our solar system, after the storms that form here on Earth," said the University of Oxford's Leigh Fletcher, who was lead author for the study appearing in the journal Icarus.

But it requires extraordinary resolution to measure the temperature differences within the spot. Not even NASA's Galileo spacecraft, which observed Jupiter from orbit for almost eight years, could detect the warm core. it was finally spotted using the VISIR mid-infrared spectrometer and imager on the ESO's Very Large Telescope in Chile.

"I was almost in tears when I first saw the detail popping up in our first thermal images of Jupiter, because in minutes we were getting across the entire planet what it took us years of effort to get in little areas at the time with Galileo," Orton told me. These first observations were from the Subaru Telescope in Hawaii, which along with the Gemini South telescope in Chile contributed data to the research effort.

The Great Red Spot's intensely orange-red core is "warm" only in relative terms. Across the entire extent of the storm, temperatures average about 256 degrees below zero Fahrenheit (-160 degrees Celsius). But Fletcher said the core is 3 to 4 degrees C (5 to 7 degrees F) warmer than the area around it. That would be enough to explain the change in circulation, from counterclockwise at the edges to weakly clockwise in the core. What's more, the core material is sinking down while the outer material is welling up, Orton said.

Rise and fall of Red Spots
The Great Red Spot has often been compared to a terrestrial hurricane, but Orton said that's not quite right: Unlike Earth's low-pressure hurricanes, the Jovian twister is a high-pressure storm. "It's sort of an anti-hurricane," he said.

It's also not quite as great as it used to be. "If you saw it a century ago, you'd call it the Great Red Sausage," Orton said. "And it should be the Great Red Circle in about 2050."

While the Great Red Spot is slowly lessening, another storm, known as Oval BA or Red Jr., is becoming greater. Oval BA, which coalesced from smaller Jovian storms, started out as a white spot ... but turned red several years ago.

"Once every two years or so, the Great Red Spot and Oval BA come very close together," Fletcher noted, and it looks as the interactions have had a complex effect on both storms. (A third storm system, which earned the nickname Baby Red, was chewed up between the two bigger storms in 2008 and eventually disappeared.)

Studying Oval BA as well as the Great Red Spot may help scientists solve one of the biggest mysteries swirling around the storms: Why are those spots red?

"We know that Oval BA did this spectacular color change from white to red, and it's entirely possible that the interactions between BA and the Great Red Spot led to that color change," Fletcher said. "It does look like these interactions could have been a precursor to the reddening of Oval BA."

Orton thinks Oval BA's reddening is simply the result of its rise to power. As the storm strengthened, it presumably put down deeper roots in Jupiter's atmosphere, bringing up more sulfur-bearing material from the lower levels. When that material rose to the top of the clouds and was exposed to the sun's ultraviolet radiation, a chemical reaction could have brought out the reddish color.

"That's the theory I haven't published yet," Orton joked. "I need to publish that fast before someone beats me to it."

Black Spot mystery solved?
Speaking of unpublished theories, Orton and Fletcher both said they're working on research that should shed additional light on the event that left a Great Black Spot on Jupiter last summer. No one saw the event while it was happening, and researchers couldn't say at the time whether a comet or an asteroid or some weird atmospheric process was responsible.

Are researchers getting closer to solving the mystery? "Absolutely," Fletcher said. "The mystery is being solved even as we speak. I didn't expect us to be able to get quite as much information about this impact as we did."

Neither Fletcher nor Orton would say anything further, because the research is currently going through a confidential peer-review process. "In the next couple of months, we may be able to tell you the details," Fletcher said. We'll just have to stay tuned for ... the rest of the story.

Update for 7:45 p.m. ET: So what's the next step for exploration of Jupiter and its moons? NASA is due to launch the Juno mission to Jupiter in August 2011. Meanwhile, NASA and the European Space Agency are developing concepts for a joint mission to the Jovian moons Europa and Ganymede, both of which are thought to harbor oceans' worth of liquid water beneath their icy surfaces. Launch of the Europa Jupiter System Mission could come around 2020.

The team behind the study in Icarus is composed of Leigh Fletcher and P. G. J. Irwin (University of Oxford), G. S. Orton, P. Yanamandra-Fisher and B. M. Fisher (Jet Propulsion Laboratory), O. Mousis (Observatoire de Besançon and University of Arizona), P. D. Parrish (University of Edinburgh), L. Vanzi (Pontificia Universidad Catolica de Chile), T. Fujiyoshi and T. Fuse (Subaru Telescope), A.A. Simon-Miller (Goddard Space Flight Center), E. Edkins (University of California, Santa Barbara), T.L. Hayward (Gemini Observatory) and J. De Buizer (SOFIA - USRA, NASA Ames Research Center). Leigh Fletcher was working at JPL during the study.

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes an appearance on "The 1st Question" quiz show in the Second Life virtual world at 7 p.m. PT/SLT tonight, and a March 29 "Science on Tap" talk in Seattle.

	G. Neukum / FU Berlin / DLR / ESA
	Use red-blue glasses to get a 3-D view of Phobos, and click on the image for a larger version.

Fresh imagery from Europe's Mars Express orbiter shows the Martian moon Phobos in sharp, 3-D detail. This isn't the first time Phobos has gotten its close-up, but interest in the irregular moon is rising - in part because it's increasingly seen as a steppingstone for Mars-bound astronauts.

Last month, NASA shifted its focus from sending humans back to the moon to a "flexible path" that includes the moons of Mars as potential destinations. The idea is that low-gravity locales such as Phobos (and Mars' other moon, Deimos) should be easier to get to because they're more accommodating for landing and ascent.

Phobos - a pockmarked, potato-shaped lump that measures only 17 miles (27 kilometers) in its widest dimension - could well serve as the prime staging ground for telerobotic operations on the Martian surface, or for eventual human landings on Mars.

But first, scientists want to figure out what Phobos is made of.

That's the aim of a $72 million Russian-Chinese mission known as Phobos-Grunt ("Phobos-Soil" in Russian). The current plan calls for the probe to be launched from Russia's Baikonur Cosmodrome in Kazakhstan in 2011, aiming for a soft landing on Phobos. The lander would dig up samples of rock and soil, load them into a return capsule and send them back to Earth. Meanwhile, a Chinese-built microsatellite would go into Martian orbit.

The newly released pictures from Mars Express, acquired on March 7, focus on the area where Phobos-Grunt is expected to land  - and they provide some good news for the sometimes-troubled mission.

"We got very good images of the proposed landing sites for Phobos-Grunt … better than anything before," Gerhard Neukum, a professor at the Freie Universität Berlin and principal investigator for Mars Express' high-resolution camera, told me today. "It's difficult to see [the area] under sunlit conditions. We tried to make the timing in such a way that we would get the best positions possible."

These pictures were taken from a distance of 80 miles (130 kilometers), yielding a resolution of 14 feet (4.4 meters) per pixel. Previous views of Phobos have achieved a higher resolution, but the Phobos-Grunt sites were seen edge-on or in shadow. The new images were designed to verify that mission planners made the right choice for their landing site.

"If it showed a very rough terrain, they might change it. … Fortunately, the area they chose originally is not too bad. It's relatively smooth," Neukum said. "It's not as dangerous as other areas where they could land. We don't see any big impact close by, so there shouldn't be any big blocks."

G. Neukum / FU Berlin / DLR / ESA

Mars Express' view of the moon Phobos provides a good look at the proposed landing sites for the Phobos-Grunt probe, shown as red dots in the inset photo.

Phobos poses plenty of mysteries: Is it an asteroid that was gravitationally captured by Mars, as its shape and composition suggest? Or did it come into existence along with the Red Planet, as its orbit suggests? Is it actually a big piece of Mars that was struck off by a meteor impact? Does ice lie beneath its surface? Could material blasted away from Mars settle onto Phobos' surface, and might some of that material contain evidence of life?

One of the experiments hitchhiking on Phobos-Grunt is designed to find out whether organisms could survive the trip from Mars to Earth - testing a hypothesis for life's interplanetary spread known as "panspermia."

Yet another proposed mission to Phobos, called PRIME, would take a close look at feature that seems to be a monolith rising up from the moon's surface. "When people find out about that, they're going to say, 'Who put that there? Who put that there?'" Apollo moonwalker Buzz Aldrin observed in a widely distributed video clip. "Well, the universe put it there. If you choose, God put it there."

Mars Express isn't done with Phobos yet: Neukum said scientists are still analyzing the data from a March 3 flyby that was aimed at mapping the moon's gravitational field and internal structure. Still more flybys are planned in the weeks and months ahead, including a series that should bring the orbiter within 37 miles (60 kilometers) of Phobos' surface.

Neukum is looking forward to those improved views of Mars' mysterious moon. "We are not disappointed, but we could have done better," he told me. "There will be more opportunities."

More on Mars' moons:

• Martian moons pictured together for first time
• See a solar eclipse from the Red Planet
• More solar eclipses, starring Phobos and Deimos
• A 'lunar' eclipse as seen by NASA's Spirit rover

Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto." The book promotion schedule includes a Tuesday appearance on "The 1st Question" quiz show in the Second Life virtual world, and a March 29 "Science on Tap" talk in Seattle.

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Greenwood Space Travel Supply Co.

A stylized postcard from Seattle's Greenwood Space Travel Supply Co. celebrates Pluto and its moons. The company is planning a tongue-in-cheek teach-in and rally at 1 p.m. PT Saturday to protest Pluto's plight.

It's sad to see how many people are willing to kick a dwarf planet when it's down. Take Pluto, for instance: A couple of years ago, when I visited a "solar system walk" that was erected near my hometown in Iowa, there was a big black X drawn across Pluto's name - as if it didn't belong in the lineup because of its controversial reclassification in 2006.

That was one of the reasons why I wrote "The Case for Pluto." I felt as if somebody had to stand up for the little guy. (You can read all about my Iowa encounter here.)

I'm feeling a lot better these days: Over the past week, I've been in Iowa, Wisconsin and Illinois to talk with Midwesterners about the book, and I've been heartened by the experience. Although the faded X can still be seen on the solar system monument in Mount Vernon, it looks as if Pluto and its little pals are finding their proper place, figuratively and literally.

That's a particularly apt development for 2010, which marks the 80th anniversary of Pluto's discovery. Feb. 18 was Pluto Discovery Day, celebrating the date when farmboy-turned-astronomer Clyde Tombaugh spotted the new world. Another milestone comes on Saturday: That's the anniversary of the Lowell Observatory's announcement of the find.

March 13 was an important date on the observatory's calendar back then, because it was the birthday of the facility's late founder, Percival Lowell, as well as the day when English astronomer William Herschel discovered Uranus in 1781. That's why the Pluto announcement was carefully planned for March 13 in 1930. The date retained its significance after Pluto's reclassification, when the New Mexico and Illinois legislatures chose March 13 for their rebel-rousing "Planet Pluto" observances.

One of the centers for this year's Pluto rebellion is Seattle, where the Greenwood Space Travel Supply Co. is planning a Saturday teach-in and rally to protest the indignities suffered by the dwarf planet (and poke a bit of fun). During the lead-up to the rally, writers have been invited to work up "persuasive essays on whether Pluto should be a planet or not be a planet," said Justin Allan, store manager and event organizer.

Allan admitted that the Seattle crowd might be a bit biased on the pro- or anti-Pluto question: "Most of them pick 'pro,'" he told me.

Meanderings in the Midwest
Normally, that'd be my kind of event, especially since my home is just a few miles east of Seattle. But instead, I'm in the Illinois town of Streator, where Clyde Tombaugh was born, to talk with students and residents about Pluto and the latest chapters in the saga of planetary science.

It's been a great month for Streatorites, who came off looking pretty good in "The Pluto Files," a documentary broadcast on public-TV stations last week. "Since 'The Pluto Files' aired on PBS, we have been inundated with inquiries about Pluto events," Ed Brozak, the town's tourism director, told me.

Today, I'll be participating in some of those events: I'm scheduled to visit Streator's schools and City Hall to talk about Pluto, the history of the search for planets and where discoveries to come might take us.

I'm not the only one trying to put Pluto in its rightful place: On Wednesday, Jim Lattis, an astronomer at the University of Wisconsin at Madison and director of the university's Space Place outreach center, filled me in on the status of Dane County's Planet Trek.

Like Mount Vernon's solar system walk, the Planet Trek bike trail was designed to provide a down-to-earth perspective on planetary distances. When the course was put together last spring, the 865,000-mile-wide sun was represented by a 24-foot-wide circle. Signs standing for the various planets were erected at points spaced apart using the same scale. Mercury was just 0.19 miles away in central Madison. Pluto was at the end of the line, 23.8 miles away in Mount Horeb.

UW-Madison

Jim Lattis, Ella Braden, Nick Schweitzer and John Rummel "plant" the sign for Pluto in Mount Horeb, Wis., during construction of the Planet Trek in May 2009. The bike route signs were taken down last October but are due to go up again in April.

The signs were taken down for the winter, but Lattis is getting ready to re-erect them in April. He's also looking for contributors who'd be willing to support a permanent set of spiffier planetary monuments.

Lattis said he hasn't gotten all that much grief over including Pluto as well as Ceres, another dwarf planet that is the largest thing in the asteroid belt. "Some people would say, 'But Pluto isn't a planet anymore,' but I'd say, 'Well, it's still part of the solar system,'" he told me.

He thinks the dwarf-planet designation, which was created when Pluto was reclassified, will be handy in the years to come as more such objects are discovered on the solar system's icy rim. "By one name or another, astronomers are trying to distinguish these objects that are big enough to deform themselves into spheres by self-gravity," he said. "It's a natural enough definition."

Pluto also stayed in the picture when Connecticut's McCarthy Observatory unveiled its own planet walk last November.

"When someone says the earth is 93 million miles from the sun, my mind can't grasp that," Bill Quinnell, the chairman of the observatory's board of directors, told The (Danbury) News-Times. "But when they say, imagine the sun is six feet in diameter and, if you want to argue about whether Pluto is a planet or not, you're going to have to go to Canterbury School to see - that I can wrap my mind around."

When it comes to wrapping your mind around the structure of our solar system, it's better to have more than less. At the McCarthy Observatory, there are monuments for the Kuiper Belt and the Oort Cloud on the solar system's fringe, plus a marker that serves as the "gateway to the galaxy." (If I had the power to add just one more monument, I'd probably go with Ceres and the asteroid belt.)

Modeling the solar system
Actually, anyone has the power to build a solar system model, thanks to Web pages like this one (and this one). San Francisco's Exploratorium has a Web page that lets you choose how big you want your solar system to be, and then runs the numbers for sizes and distances of the scaled-down planets.

One of my favorite scale models is at New York's American Museum of Natural History, which played such a prominent role in "The Pluto Files." The Hayden Planetarium is built into an 87-foot-wide sphere that stands in for the sun. Jupiter is about 9 feet wide, Earth is the size of a basketball (10 inches), and Mercury is the size of a softball (4 inches).

The biggest drawback is that the display downplays Pluto and the other small fry. You can get an idea of the size comparison by looking at the picture on the "Where's Pluto" plaque - but if you bring a handball to the museum (1.875 inches wide), you'll get the full 3-D perspective. Eris, the only known dwarf planet larger than Pluto, would be just a bit bigger. Ceres would be significantly smaller, about as wide as a penny or a marble.

If you were to arrange the museum's scaled-down planets to reflect their scaled-down distances from the sun, Earth would be about 1.8 miles away. Pluto would be 58 miles away. Eris would be 175 miles away. It turns out that a bicyclist could travel this scaled-down solar system at the equivalent of the speed of light in the real universe (8 minutes to Earth, 4.4 hours to Pluto, 13.4 hours to Eris).

But don't expect to ride your bike to the next star over: Even in this scaled-down universe, Proxima Centauri would be almost 487,000 miles away - more than twice as far as the real-life moon. That's just one more way to get across the message that space is vastly, hugely, mind-bogglingly big - and that all the bits of rock and ice in our own solar system are mind-bogglingly small.

If that doesn't put us in our place, nothing will.

But wait ... there's more
This weekend offers one more red-letter day on the scientific calendar: Sunday, March 14, is Albert Einstein's birthday as well as Pi Day. (Get it? 3.14...) You can add more digits to the Pi party by celebrating at precisely 1:59:26 p.m.

Pi Day got its start at the Exploratorium in 1988, as I explained in this 20th-anniversary Pi Day posting. The traditional observances include marching around in a circle, feasting on pie (pizza or dessert) and performing feats of geek prowess (such as reciting the first n digits of pi). You can do a pi-mile run (about 5K) or watch the movie "Pi" on DVD. This WikiHow page provides another round of suggestions.

But don't party yourself out completely. You'll need to keep up your strength for next month's space-geek holiday, Yuri's Night.