NASA

Images from NASA's Terra satellite show the coastline of Japan's Honshu island in the area around Sendai before and after Friday's earthquake. The left image is from Feb. 26, and the right image is from today. The images are color-coded to reflect surface composition rather than what the eye would see. The "Flood" label helps you gauge the extent of the flooding caused by the tsunami that followed the quake.

This week's earthquake caused the main island of Japan to shift as much as 13 feet to the east, seismologists say. That may sound like a shocker, but it's just one of the natural changes that come along with an 8.9-magnitude temblor — like the 1.8-microsecond speed-up of Earth's daily rotation and the 6.5-inch shift in Earth's axis.

The eastward shift was documented by Japan's Geonet network of GPS monitoring stations, based in Tsukuba, said Ken Hudnut, a geophysicist at the U.S. Geological Survey's Earthquake Hazards Program in Pasadena, Calif. Similar shifts took place during last year's 8.8 earthquake off the Chilean coast, as well as the 9.1 earthquake near Sumatra that caused a disastrous tsunami in 2004.

"It's the same phenomenon in all three cases," Hudnut said. The movement is linked to the release of the strain that builds up when one tectonic plate grinds against another in a subduction zone. 

"What's going on is that the plate going down drags along with it the upper plate as strain is stored in between earthquakes," he explained. "When the earthquake occurs, the upper plate lurches eastward over the subducting plate. The oceanic plate that's going down is relatively rigid, but the upper plate is like a wedge of material that's more elastic. So picture that upper wedge as being almost like an accordion that's being compressed between the times of earthquakes. It's like a spring. You're loading up the spring between earthquakes — in other words, you're compressing the eastern edge of the spring toward the main island of Japan. The earthquake allows that material to spring out toward the east."

Japan's network of 1,200 GPS monitoring stations, operated by the Geographical Survey Institute, shows a maximum springing-out effect of 13 feet (4 meters), with an average displacement of about 8 feet (2.5 meters) along a stretch measuring more than 300 miles (500 kilometers).

Everything that links GPS readings to maps, ranging from driving directions to property records, will have to be changed as a result of the shift, Hudnut told me. "Their national network for property boundary definitions has been warped," he said in an e-mail. "For ships, the nautical charts will need revision due to changed water depths, too (of about 3 feet). Much of the coastline dropped by a few feet, too, we gather."

We're starting to get pictures from space that document how the coastline has changed due to the earthquake and the tsunami. The NASA photos at the top of this posting show the coastline around the city of Sendai, which was one of the hardest-hit areas. The left photo was taken on Feb. 26 by the Moderate Resolution Imaging Spectrometer, or MODIS, aboard NASA's Terra satellite. The right photo was taken today by the same instrument. You can see that wide stretches of the coast are still flooded, in part because barriers erected at the coastline's edge are now keeping water in rather than keeping it out.

Other satellite pictures, distributed by Google, provide a closer-in view of the devastation caused by the tsunami. In each of the before-and-after sets below, the left picture was taken before the earthquake and the right picture was taken afterward. We've put together an eye-opening slideshow of before-and-after imagery that gives you control of the slider. And you can check out Google's blog posting and this Picasa Web album for still more.

Google / GeoEye / DigitalGlobe

Satellite photos provide before-and-after views of Kamaishi, a coastal city north of Sendai in Japan.

Google

These photos show before-and-after views of Japanese communities, with the left views taken before the earthquake and the right view taken today. The upper set shows Yuriagi and the lower set shows Yagawahama, both in Japan's hard-hit Miyagi prefecture.

Update for 7:25 p.m. ET March 13: I've updated the figures for the change in the day's length and the position of Earth's axis to reflect fresh figures from Richard Gross, a geophysicist at NASA's Jet Propulsion Laboratory.

More post-earthquake imagery:

• Slideshow: Japan before and after the tsunami
• Satellite photos show scope of Sendai damage
• Japan's devastation documented by satellites
• Slideshow: Japan struggles to recover from quake 

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

NASA

An artist's conception shows NASA's New Horizons probe at Pluto.

Few folks involved in the space effort span as wide a spectrum as Alan Stern: The 53-year-old planetary scientist is working to get himself and other researchers onto suborbital space planes to do science — and he's also heading up the science team for one of NASA's farthest-flung space efforts, the New Horizons mission to Pluto.

New Horizons is due to reach the dwarf planet by 2015, putting Pluto back in the international spotlight. And by that time, Stern may well have taken a trip to outer space himself — perhaps in XCOR Aerospace's Lynx rocket plane or Virgin Galactic's VSS Enterprise. We'll talk about Pluto as well as the pioneering efforts to commercialize space travel during "Virtually Speaking Science," at 10 p.m. ET Sunday on BlogTalkRadio and in the Second Life virtual world.

It's unusually fitting that Sunday's show features a chat with Stern, who is a former NASA associate administrator and currently serves as associate vice president for research and development for the Southwest Research Institute's Space Science and Engineering Division. Sunday happens to mark the 81st anniversary of the Lowell Observatory's announcement of Pluto's discovery.

Some folks have gone so far as to celebrate March 13 as "Planet Pluto Day." This year, the Greenwood Space Travel Co. in Seattle will get a jump on the holiday by holding its annual pro-Pluto rally at 2 p.m. PT Saturday, one day before the anniversary. I'll be there, of course, talking about the state of the planet search and about my book, "The Case for Pluto."

Maybe I'll see you at the march protesting the International Astronomical Union's putdown of Pluto and other dwarf planets. "It's not a long march — just down the street and back," Justin Allan, store manager at Greenwood Space Travel, told me.

Even if you're a Pluto-hater, you'll be welcome. The beauty of the Pluto protest is that it doesn't take itself too seriously. I wish the same could be said of everyone who's been involved in the planethood debate.

If you can't make it to Seattle on Saturday, please tune in for Sunday's show. To get ready for the program, I e-mailed Stern a few questions about his twin interests, Pluto and private spaceflight. Here's an edited version of the quick Q&A:

Cosmic Log: You're involved in so many different angles of the space frontier ... is there a unifying principle that ties all of them together?

Alan Stern: Well, I work on what I am interested in and where I think I can make a difference.

Q: What's the status of the New Horizons mission? It sounds as if the spacecraft is back in hibernation, but I'm sure that doesn't mean that the science team is hibernating as well....

A: New Horizons is doing very well — we're just now crossing the orbit of Uranus and in great shape from every perspective. We're even planning the details of the Pluto system encounter already.

Q: How has the scientific perspective on Pluto changed in the past year, or in the past five years? Some folks, such as Caltech astronomer Mike Brown [who discovered the dwarf planet that led to Pluto's downfall], say only a very few scientists are still arguing to have Pluto put in the planet category. I'm guessing that's not your perception.

A: Mike knows that's not so.

Q: Do you think developments in the Dawn mission (for example, the Vesta observations expected this year) will have any effect on the scientific discussions about small bodies in the solar system? Any dramatic results that may come to light?

A: Hard to tell. Maybe, but Dawn is visiting much smaller words than Pluto — Vesta and Ceres could together fit inside Pluto about 15 times!

Q: On commercial space, how do you think the recent suborbital research conference changed the landscape for spaceflight? How do you see the next year shaping up on the commercial front, for suborbital as well as orbital ventures?

A: The next year will be very important, because many of the suborbital companies will be testing their vehicles in flight and even making missions to space.

Q: What do you think will come out of the current deliberations involving NASA and the would-be providers of commercial space taxis for the International Space Station?

A: Several viable commercial crew capsules will be the most likely development, along with launchers than can be man-rated for these capsules to fly on.

Q: What are your thoughts on the decadal report for planetary science. You're a planetary scientist who had to struggle to get your mission to Pluto funded, as well as a former NASA official who had to struggle with planetary mission cutbacks ... what strategy would you suggest for moving forward with the missions on the table for the next decade? Do you think the decadal survey came up with the right strategy?

A: It was a great effort by the planetary community. Unfortunately, owing to the increasing costs of missions and overrun pressures, the next decade looks bleaker than the past one.

How do your opinions line up with Stern's? Tune in via the Web on Sunday to chat with Stern, co-host Robin Snelson of the Space Studies Institute and yours truly. And, oh, by the way ... Happy Pluto Day!

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter.

Japan has spent well more than $1 billion on earthquake prediction systems, including a network of more than 1,000 GPS-based sensors scattered around the country — and the payoff came today when Tokyo's residents were given up to a minute's warning that a Big One was on the way. That may not sound like much, but it's enough time for people to switch off their gas lines and get beneath a table or a door frame.

"The system functioned well, because warnings were seen on television across the country," Hirohito Naito, a seismic expert at the Japan Meterological Agency, told AFP.

The agency is in charge of quake preparedness as well as weather forecasting, and researchers have invested decades of effort into Japan's early-warning system. It's considered a model for the rest of the world, and U.S. researchers are adapting it for a system known as the California Integrated Seismic Network.

The system capitalizes on the fact that a seismic event sends out two types of shock waves: primary or P-waves, which move up and down; and secondary or S-waves, which shake from side to side. The P-waves travel faster but are weaker, while the S-waves are slower but do more damage. When Japan's system picks up the P-waves, it calculates how far away the source of the shaking is and issues an alarm while the S-waves are still en route. A warning can be broadcast via TV, radio, cell phones and home alarms less than 10 seconds after the P-waves are detected.

The early warning system isn't that useful for those who are close to the epicenter, because the S-waves come quickly behind the P-waves. But because Tokyo is about 230 miles away, that city's residents could have taken action as much as 80 seconds before the serious shaking began. As noted in this Technology Review report, that amount of time can give people a chance to stop a train, lower a crane, pull a car over to the side of the road, stop performing surgery in a hospital or get off an elevator in an office building.

That's assuming that you get the alarm immediately, of course. Some reports from Japan suggested that the alarms provided somewhat less advance warning, in the range of 15 to 30 seconds. This webpage from the Japan Meteorological Agency explains the early-warning system in much more depth.

Tsunami warnings worked
It takes longer to issue a tsunami warning, because that's dependent on an analysis of wave propagation from an undersea seismic source. The Japanese government issued a local warning three minutes after the quake struck. Technology Review estimates that residents in the hardest-hit coastal areas had 15 minutes of warning, and that Tokyo would have had at least 40 minutes to prepare.

Meanwhile, experts at the National Oceanic and Atmospheric Administration's Pacific Tsunami Warning Center (in Hawaii) and West Coast/Alaska Tsunami Warning Center (in Alaska) issued their first alerts nine minutes after the earthquake. They used computer modeling as well as readings from ocean buoys to track the waves as they sped across the Pacific at jetliner speeds. The wave-monitoring system has been beefed up significantly since the 2004 Indian Ocean tsunami, which pointed up gaps in the network.

Tsunami forecasters and emergency officials called for an evacuation of coastal areas in Hawaii, which were hit by walls of water measuring as much as 7 feet high.

"We called this right," Gerard Fryer, a geophysicist for the Pacific Tsunami Warning Center, told The Associated Press. "This evacuation was necessary. There's absolutely no question, this was the right thing to do."

Longer-term predictions
Could today's quake have been predicted days in advance rather than seconds in advance? In retrospect, maybe so: A 7.4-magnitude quake that hit Japan on Wednesday is now thought to be a foreshock heralding the bigger quake to come.

Two years ago, researchers looked at the records from Japan's crustal movement sensors and determined that large quakes could be anticipated by analyzing the "pre-signals" in the seismic data.

Then again, it's always easier to predict an event in retrospect. Five years ago, The Washington Post's Joel Achenbach wrote that Japanese geologists were sure the next Big One would take place southwest of Tokyo. Today's quake certainly qualifies as that Big One ... but it happened to the northeast, not the southwest.

More about earthquake prediction:

• 8.7 ideas for earthquake prediction
• Quake technology buys time for Japan
• Cosmic Log coverage of the Japan quake
• Can't predict the Big One? Bring on the pets!
• More from msnbc.com's Asia-Pacific news section

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

Dan Callister / Getty Images file

Located just 50 miles off the coast, the 680-mile-long Cascadia fault has lain dormant for 300 years. When it wakes, it could trigger an earthquake and tsunami similar to the one that struck Japan today.

As the world tunes in to the disaster following the earthquake and tsunami in Japan today — and with waves rattling nerves along the U.S. West Coast and Hawaii — a question rises to the fore: Could such a disaster happen here?

The short answer is yes. It already has. Major quakes of a similar style rupture along the 680-mile-long Cascadia subduction zone, a fault that runs from Northern California to British Columbia, every few hundred years. They trigger tsunami waves reaching up to 15 feet high that hit the shore about 10 to 15 minutes later.

The fault last ruptured in 1700 – a magnitude-9 event that sent tsunami waves crashing into Japan. Experts believe it is a matter of when, not if, the next one will happen, according to Brian Atwater, a geologist with the U.S. Geological Survey and the University of Washington and an expert on the 1700 event.

"There's no reason to question the history here," he told me today.

Recent computer simulations of a hypothetical magnitude-9 quake on the Cascadia subduction zone found that shaking could last two to five minutes, strong enough to collapse poorly constructed buildings and damage highways and bridges. Powerful tsunami waves could rush ashore minutes later, potentially devastating coastal communities.

The threat is greatest along the northern part of the West Coast. Caltech seismologist Kate Huttontold MSNBC today that Southern California doesn’t have subduction zones like the Cascadia fault.

According to calculations by Chris Goldfinger, a geologist at Oregon State University, there's an 80 percent chance that the portion of the fault off southern Oregon and Northern California would break in the next 50 years. The odds are lower — 27 percent for the same time period — for Washington state and Canada's Vancouver Island.

"People try to compute these earthquake weather forecasts by taking into account 300 years have passed since the last one and the fault has been busy putting money in the bank to spend on the next earthquake," Atwater explained. "So the more time that passes, the better the car the fault can buy."

Even though authorities have been aware of the risk for years, the Pacific Northwest is not adequately prepared, according to geotechnical engineer Yumei Wang of the Oregon Department of Geology and Mineral Industries.

"People are in a really dangerous position," Wang told Discovery News in 2009. "This is going to happen, and it's going to have really bad ramifications unless we do something."

She has proposed building a series of tsunami shelters up and down the coast. As well, work is ongoing to shore up schools, hospitals and other buildings. Similar efforts are under way in Seattle, Brian Gaff of the city's Office of Emergency Management, told the AP.

Part of the problem is that scientific knowledge about the Cascadia subduction zone is way out in front of public policy, laws and building codes, Edward Wolf, a private consultant and writer in Oregon who works closely Wang, told me today.

"It's analogous to climate change. The science is considerably ahead of public awareness and policy response," he said.

To date, attention has been put into mapping tsunami inundation zones, plotting evacuation routes and preparing signage to inform people about the risk. "But there are still some low-lying coastal areas with difficult access to evacuation that would be difficult to impossible to evacuate in the event of an earthquake," he said.

Proposals such as Wang's for shelters that can withstand tsunami waves have been floated. Another idea is to construct large earthen mounds that are high enough and accessible enough to serve as a tsunami refuge in regions such as southwest Washington's Long Beach Peninsula. None of these proposals has been funded.

Although the risk for an earthquake and tsunami like the one in Japan is very real for the West Coast, there is no scientific evidence to suggest that today's temblor will trigger a quake on the Cascadia subduction zone. But, as Atwater emphasized, "It's not a matter of if, but when, the next one will happen."

Related stories:

• Tsunami threat looms over Pacific Northwest
• Pacific Northwest overdue for big one
• Pacific Northwest at risk for a mega quake
• Tsunami awes even the experts

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

NOAA Center for Tsunami Research

This graphic shows how waves generated by Japan's Honshu earthquake propagated across the Pacific Ocean, based on computer models. The different colors indicate different wave heights, as indicated by the key at lower right. Click on the graphic to watch a video showing the progress of the waves.

Seismic experts have long known that Japan’s complex undersea fault system is capable of unleashing great waves, but today's 8.9-magnitude quake was the most violent shock to hit the nation in the past century. And tsunami geologist Jody Bourgeois of the University of Washington was there to feel it for herself, on the Japanese island of Hokkaido.

"The shaking didn't seem really strong, but it just kept going," she told me today during a Skype phone call. "I felt like I was seasick, which was really strange."

Bourgeois is working with other seismic experts this winter at the University of Hokkaido in Sapporo, about 300 miles north of the quake's epicenter, and she's been keeping track of Japan's recent spate of seismic activity — including a 7.2 quake that struck off the Japanese coast on Wednesday.

"I was sitting at my desk today, not really thinking we're going to get another earthquake, and then the room started to move," she said. "I didn't hear any people suggest that the 7.2 might be a foreshock. ... But now you realize that those were just the forerunners."

The quake, which ranks as the world's fifth-strongest seismic event of the past century, was centered near the southern end of an undersea subduction zone that extends from Russia's Kamchatka Peninsula and the Kuril Islands to the Japanese islands. Such a zone, where one tectonic plate dives beneath another, is a classic generator of tsunami waves.

"Japan's very complicated because they've got several different plates coming together here," Bourgeois explained.

Specifically, the quake occurred "in the subduction zone of the Japan Trench where the Pacific Plate subducts under the Honshu island of Japan, part of the Okhotsk Plate, at a rate of about 8 centimeters per year," Jayanta Guin, senior vice president of research for AIR Worldwide, said in an advisory.

Quake history goes back centuries
Paul Caruso, a geophysicist at the U.S. Geological Survey, said the quake occurred in one of the world's most seismically active regions. "That area has had nine earthquakes above magnitude 7 since 1973," he said.

An undersea quake measuring 8.2 to 9.0 in magnitude occurred in the same subduction zone off the coast of Kamchatka in 1952, generating a Pacific-wide tsunami that caused considerable damage and loss of life in Russia. Japan's deadliest quake, a 7.9 shock that killed more than 140,000 people in 1923, occurred south of today's epicenter on the main island of Honshu.

Going farther back, Bourgeois said core samples indicate that Japan's Sendai Plain was hit by a strong earthquake and tsunami back in the year 869. Some experts believe this was the strongest seismic disturbance to hit Japan in recorded history.

The same area, including Sendai's airport, was hit the hardest by today's quake. "It's been 1,200 years since they had one this large," Bourgeois said.

Other danger zones
Bourgeois said the same kind of offshore subduction zone was implicated in the magnitude-8.8 earthquake that did so much damage a year ago. A stronger subduction seaquake, pegged at magnitude 9.1, caused the tsunami that swept through the Indian Ocean in 2004, causing more than 200,000 deaths around the Pacific Rim.

Just last year, seismologists reported that the Bourgeois' home base — the Pacific Northwest — is vulnerable to the same kind of earthquake and tsunami. The 680-mile-long Cascadia fault has been dormant for 300 years, and seismologists say there's an 80 percent chance that the portion of the fault off southern Oregon and northern California could produce a megaquake in the next 50 years.

Aftershocks have been continuing in Japan, more than 12 hours after the 8.9 shock occurred, and they may continue for days or weeks longer. "We can expect a lot of aftershocks," Caltech seismologist Kate Hutton told MSNBC.

Bourgeois doesn't intend to stay holed up in her office. "I know at least one group that's going out tomorrow to the coast," she said. But she also doesn't intend to get in the way.

"We go out basically after a tsunami, when people are safe and you're not going to interfere with the local rescue efforts," Bourgeois said. "We're interested in everything — what kind of damage the tsunami did, how high the currents were. I'm interested in what kind of record the tsunami left behind, and Japan is very well set up for these kinds of surveys."

More on the Japan quake and tsunami:

• Hundreds dead after Japan's seismic shock
• Radiation risk as Japan nuke reactor heats up
• How quake prediction works (or doesn't)
• Could similar disaster hit the U.S. someday? Yes
• Tsunami waves hit Hawaii, California coast
• Interactive: How a tsunami forms

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

Do you want to explore the heavens? Learn about chemistry or biology? Delve into dinosaur fossils? There's an app for that ... and for that ... and for that as well. Chances are you wouldn't buy an electronic tablet just to study the solar system or the human body, but if you already have an iPad or are considering the new iPad 2, science-based apps can make in-depth learning as fun as playing a video game. Check out these apps for the iPad, and tell us about your own favorite educational apps for tablets or mobile devices (iPad, Android, Windows, BlackBerry, WebOS ... you name it).

Solar System (Touch Press, $14): So much has been learned about the solar system in the past couple of decades that it's no longer enough to memorize the names of eight (or nine) worlds. Thankfully, this app doesn't stop with the biggies, but goes on to include Pluto and Eris, Ceres and other dwarf planets, asteroids, Kuiper Belt objects ... all the objects we cover in our own "New Solar System" interactive, but with much greater depth. There's also an "orrery" that lets you zoom in on planets and give 'em a spin. Links to the Wolfram Alpha database give you basic stats on solar system objects, including where they are right now. It's not perfect — I'd love it if the software could work with the Web to plot the location of smaller objects. (For example, what's up with Apophis, and where will it be in 2029?) But all in all, it's a beautiful app that's well worth the price.

Exoplanet (Hanno Rein, free): What about new worlds beyond the solar system? The Exoplanet app for iPad, iPhone and iTouch shows you where the more than 500 detected exoplanets lie, and how their sizes and orbits compare. The software's tutorials explain how astronomers find distant planets, and you can set up notifications for every new discovery that's made. And you can't beat the price.

Star Walk (Vito Technology, $5 for iPad): Trace stars, planets and constellations in the night sky, and find out when and where to look for celestial objects as well as fast-moving satellites (including the International Space Station). The iPhone version costs $3 and includes an augmented-reality feature. Point the phone up into the sky to figure out what you're looking at.

The Elements (Touch Press, $14): This encyclopedia of the periodic table was produced by the same folks behind Solar System for iPad, and the touch-screen interface is similar. Beautiful photos show you the chemical elements in all their spinnable 3-D glory, plus the basic facts about each one — plus links to Wolfram Alpha for even more information.

Human Atlas HD (Blausen, $30): It's the priciest app on this list, but chock-full of videos and graphics that explain the workings of the human body. This app is designed to be used principally by physicians to help their patients understand what's ailing them, but it's also a boon to armchair anatomists (and, I suppose, hypochondriacs as well). Android, BlackBerry and iPhone versions of the atlas are somewhat less expensive ($20). 

3D Brain (CSHL, free): If it's neurons you're interested in, Cold Spring Harbor Laboratory has a free app for the iPad and iPhone that guides you through the human brain. It's a spinnable 3-D version of our own "Road Map to the Mind" interactive, but without the scary spider. There's also a Web version of 3D Brain. 

World Atlas HD (National Geographic, $2): The iPad already has maps, but every household should have a world atlas as well. It's hard to beat this price for an iPad atlas from the world's most respected geographers. And when you're connected to the Internet, you can zoom right down to street level.

Ultimate Dinopedia (National Geographic, $6): This kid-friendly app provides basic facts as well as videos, interactives and artwork covering more than 700 dinosaur species.

That's eight science-themed apps to start with, but there are plenty more in the online stores for all sorts of mobile devices. What are your favorites? Feel free to add your recommendations in the comment space below.

More iPad goodness:

• What you need to know about buying an iPad 2
• iPad 2 review: It's the tablet to beat
• 10 great games for your new (or old) iPad 

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

Retired Air Force Capt. Robert Salas says he was at Malmstrom Air Force Base in Montana when UFOs hovered over the base in 1967 and nuclear missile launch systems somehow went non-operational. So you might think that watching the latest alien-attack movie, "Battle: Los Angeles," would cause him some sleepless nights.

Not really.

Salas doesn't think the aliens are in any mood to launch a globe-shattering strike like the one in the movie. "If they were going to attack, they would have done it by now," said Salas, who serves as a consultant for the film project. "They could have caused a lot more destruction ... but all they did was shut our missiles down."

For the folks who truly believe we've been visited by extraterrestrial craft, "Battle: Los Angeles" (opening Friday) and other E.T. thrillers provide additional opportunities to keep UFOs in the public consciousness. Which is why Salas is touting the film. "I think the public is taking more of an interest in this subject," Salas told me this week. "Of course, just about all these movies are going to be a little on the extreme side, but it continues to be of interest."

Even if you're not ready to give credence to reports of alien visitations, there are plenty of stories in the news that serve to stoke the interest in strange phenomena. William Birnes, who is the publisher of UFO magazine and a consultant for "UFO Hunters" as well as other TV projects, pointed to three such stories from just the past month.

• Last week, the British government released 8,500 pages' worth of reports on UFO sightings, ranging from obvious misunderstandings to still-unsolved mysteries. "What it shows is that there are active discussions and investigations going on among the defense departments of First World governments about the existence of extraterrestrial craft and the potential threat to national security," Birnes said. "The back-door message is, 'Yes, we are monitoring this, and although we haven't found anything yet, if you thought that your government wasn't concernedf about the existence of UFOs, we are.'"
• Scientists have been debating whether or not meteorites linked to the early solar system contain microbes from beyond Earth. "The UFO community eats this stuff up," Birnes said. "They love this. Why? Because it is scientific validation for one of the premises of the UFO community's investigation of whether there's life out there in the universe. ... When people laugh at us and say, 'Oh, you guys wear tinfoil hats, [we can say] our own government is spending a lot of money on this."
• IBM's Watson supercomputer vanquished two of the top human champions on TV's "Jeopardy" trivia game show. "That's a real fear ... creating a machine that will start using this amoral machine logic," Birnes said. "They figure out that since human beings are doing the polluting, they'll get rid of us."

Over the decades, fear has been a strong theme in E.T. movies. On one level, extraterrestrial tales serve as a convenient backdrop on which to project our own all-too-real worries. In the 1950s, movies such as "The Day the Earth Stood Still," "War of the Worlds" and "Invasion of the Body Snatchers" were seen as Cold War parables. (All three movies inspired recent remakes that haven't stood up quite as well as parables for environmental or virological threats.)

On another level, evil-E.T. movies and other fear-inducing flicks may serve as "practice runs" for dealing with real-life threats. Psychologists have hypothesized that we're hard-wired to seek out scary experiences that unfold in a safe environment. Just as early humans gathered around the fire to hear about fights with saber-toothed cats, we gather in front of screens to watch the aliens blast LAX.

Not all movie E.T.s are terrifying, of course. The cartoon Martians in another movie opening this week, "Mars Needs Moms," get the Disney treatment. And in the 1982 movie "E.T.," the alien is the good guy and the humans are the bad guys ... which is what makes this "E.T.-X" trailer on YouTube so funny:

But for every cuddly E.T., there's an evil "Independence Day" overlord plus an rampaging "Alien" predator. Birnes said "Battle: Los Angeles" combines two of the genre's most potent fear factors: relentless killer machines (think "Terminator") and goo-filled super-insects (think "Starship Troopers").

"What are human beings most afraid of, in terms of some existential threat to the human race?" he asked. "Creatures that are repellent. Exoskeletal types of insects, primarily because we and the insects are fighting for control of the planet, in a sense."

The movie plays off yet another monster-movie meme: the unstoppable attack from above. Birnes said "Battle: Los Angeles" echoed one of the better-known chapters in UFO lore, known as "The Battle of Los Angeles."

In 1942, the city weathered what was thought at the time to be an aerlal artillery barrage, waged by phantom forces that couldn't be brought down. At first, the authorities thought it was a Japanese air raid, but the "battle" was eventually attributed to war jitters that sparked spontaneous rounds of anti-aircraft fire and flares from L.A.'s defenders.

At least that's what the authorities said. UFO aficionados, however, put the Battle of Los Angeles in the same category as Salas' close encounter in 1967, and the rash of flying-saucer sightings reported in Washington in 1952. "There's solid, solid evidence that UFOs really have interfered with the military," Birnes insisted.

That's a claim I'm not ready to agree with, though it sounds good as a movie P.R. campaign. I do, however, agree with Birnes' view that E.T. movies have an enduring hold on the popular psyche. "Science fiction movies are made because there's a huge market for science fiction," Birnes told me. "'Battle: Los Angeles' is really John Wayne meets 'Independence Day.'"

So it's time to saddle up. For solid, solid evidence that this is the year of E.T. in Hollywood, check out this list of other upcoming releases:

• "Paul" (March 18): Slacker movie where the alien (Paul) is one of the slackers. (Official movie site)
• "Apollo 18" (April 22): Why did NASA stop doing moonshots, and why was the agency's plan to send astronauts back to the moon canceled last year? Surely not because the missions were too expensive. It's because of the murderous aliens that astronauts ran across during their super-secret Apollo 18 mission. Of course. (Official movie site)
• "Super 8" (June 10): Kids use a Super 8 camera to make their own zombie movie in 1979, and stumble across a catastrophic train derailment that sets loose some hazardous alien cargo being transported from Area 51 to Wright-Patterson Air Force Base. (Official movie site) 
• "Transformers: Dark of the Moon" (July 1): Those lovable Transformers battle over an alien spacecraft hidden on the moon ... wrecking Earth and rewriting the story of Apollo 11 in the process. (Official movie site)
• "Cowboys & Aliens" (July 29): The Reese's Peanut Butter Cup of movie genres ... a star-studded Wild West posse is all that stands in the way of an alien takeover of the planet in 1873. You got cowboys in my sci-fi movie! (Official movie site)
• "The Darkest Hour" (Aug. 5): American kids in Moscow fight back against an alien invasion. 
• "The Thing" (Oct. 14): Prequel to the 1982 John Carpenter film (which itself was a remake) about a murderous E.T. that crash-lands in Antarctica.
• "Area 51" (Date not yet set): Faux documentary about teens who break into super-secret Area 51 and leave behind "found footage," a la "Paranormal Activity."

Extra credit: If you see "Battle: Los Angeles," take note of the smoke rings. Robert Salas told me that he was recently looking at purported UFO pictures taken by highway maintenance engineer Rex Heflin in California in 1965. The photos show a hat-shaped object in the sky that apparently left behind a dark, unexplained smoke ring when it zoomed off. Then Salas watched an advance screening of "Battle: Los Angeles," in which alien missiles rain down on Earth. "As I was watching the movie, lo and behold, these objects were leaving big smoke rings," Salas said.

More on aliens:

• If aliens attack: Visitors to Earth will likely be robots
• Lesson one: The aliens never, ever come in peace 
• UFO book criticized | Author strikes back
• Six signs that alien life may actually exist
• How would alien life change your life?
• Search for "extraterrestrials" on msnbc.com

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

NASA / JPL

An artist's conception shows an alien Earthlike planet.

I should have known it was too good to be true: Last month, it looked as if a world known as KOI 326.01 was the best hope among the Kepler mission's 1,235 candidates to be a second Earth. It was thought to be a bit smaller than Earth, and even better, it was located in a "habitable zone." That's the area of space surrounding a star where water could plausibly exist in liquid form. Those two characteristics — smaller than Earth, and in the habitable zone — put KOI 326.01 in a class by itself.

No more, unfortunately. A fact-checker at Discover magazine, Mara Grunbaum, called up the Kepler team for more information about the planet, presumably because it was going to be featured in a future issue. Members of the team, including San Jose State University's Natalie Batalha, double-checked their figures and determined that the planet candidate is actually somewhat warmer and much larger than originally estimated.

"The details of the planet need to be hammered out, but this certainly means that this is not an Earth-size planet in the habitable zone," Batalha is quoted as saying in a posting to the 80 Beats blog, part of Discover magazine's corner of the blogosphere. You can get the whole story behind KOI 326.01's demotion there.

That's the way it goes with these Kepler candidates: As more observations are gathered, checked and double-checked, the basic statistics for any particular candidate may need to be revised. And in some cases, the "candidate" may not exist at all. Instead, the supposed planetary detection may turn out to be merely the effect of two stars passing in front of each other. It will take months or years more to turn those candidates into confirmed planetary detections. But if you're hoping to hear about alien Earths, don't give up hope yet. Kepler's hunt continues.

More must-see science on the Web:

• Bad Astronomy: Discovery spacewalk seen from ground
• Discovery: What would an interstellar spaceship look like?
• College Humor: What pi sounds like

NASA / JPL / Univ. of Ariz.

An image from NASA's Mars Reconnaissance Orbiter shows the Opportunity rover on the rim of Santa Maria Crater (indicated by arrow) with the tracks of its wheels extending toward the left edge of the frame (visible as a faint reddish line).

Two heads are better than one, even if the "heads" happen to be the cameras built into two different space probes. Here's a fresh picture from the High Resolution Imaging Science Experiment, a camera on NASA's Mars Reconnaissance Orbiter, which shows the Opportunity rover as a speck perched on the rim of a 300-foot-wide Martian crater known as Santa Maria.

Amazingly, the tracks of the rover can be seen trailing off to the left across the plains of Meridiani Planum.

NASA often uses orbiters and rovers as a double team to identify sites of interest from the air and then investigate them on the ground. For example, the orbiter's CRISM spectrometer indicates that there is hydrated sulfate at Opportunity's location, which suggests that liquid water once flowed through the area. The rover is currently taking a closer look at the minerals to study their composition in detail. The same double team will come in handy when Opportunity travels to an even bigger hole in the Martian ground, the 14-mile-wide Endeavour Crater.

Opportunity has been going strong on Mars for more than seven years, and Mars Reconnaissance Orbiter is also in it for the long haul. NASA notes that Thursday marks the fifth anniversary of the orbiter's entry into Martian orbit. It seems like yesterday ... but since that time, MRO has sent back 131 trillion bits of data, including more than 70,000 images that are cataloged on the HiRISE website. That's more data than all other interplanetary missions combined.

Check out these links for more about Mars:

• Slideshow: People's choice pictures from HiRISE
• Mars meteorite craters: Make mine a double
• Slideshow: The greatest hits from Mars 
• Explore the 3-D depths of Mars

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto."  

NASA

In this file photo from October 1997, STS-86 Mission Specialist Scott Parazynski gets assistance from a suit technician in making adjustments to his launch and entry suit in the Operations and Checkout Building. Parazynski retired from NASA in 2009 and now is helping medical researchers build diagnostic tools. One goal is a Star Trek-like tricoder.

A former NASA astronaut known for his on-the-fly innovations aims to help a research hospital create diagnostic tools akin to the medical tricorder made famous on "Star Trek."

The medical tricorder is a fictional device that can scan a person to diagnose diseases and injuries. It has long fascinated Scott Parazynski, who last flew space shuttle Discovery in 2007 to the International Space Station and used in-house materials to fix a tear in the station's solar array.

Parazynski retired from NASA in 2009 and recently took a job as the chief medical and technology officer for the Methodist Hospital Research Institute in Houston where he plans to help investigators obtain funding and use the best technologies to meet their needs.

In an interview with the Houston Chronicle, he said he's most interested helping create the next generation of minimally invasive surgery and diagnostic tools. Inspiration, he noted, comes partially from Star Trek tech.

"As a physician growing up and watching Star Trek, we all wanted a medical tricorder," he told the paper. "So one of the things I'd love to do is think big and push the envelope on what is possible."

Attempts to build real-world tricorders have been made in the past. For example, Boris Rubinsky and colleagues at the University of California at Berkeley reported in 2008 on a tricorder-like device that couples handheld medical scanners and cell phones to detect tumors.

There's also an international push among biologists to develop handheld devices to read the "DNA barcodes" of species out in the field. This could, for example, help protect endangered species and thwart the illegal trafficking of wildlife.

Tip O' the Log to OnOrbit

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Alice Chen / Harvard-MIT

A mouse with a human-like has been created that could improve the safety and efficacy of the drug discovery pipeline. The innovation helped earn Alice Chen at Harvard-MIT win the Lemelson-MIT Student Prize.

A "humanized mouse" is among four innovations honored this year with the Lemelson-MIT Student Prize, an annual invention contest that comes with a $30,000 check.

The mouse has been outfitted with a liver that was engineered to be human-like, a step that could improve the safety and efficiency of the drug discovery process.

Other winners include a manual-powered wheelchair with an automatic gear shift that improves mobility of wheelchair users; a novel technique to detect bombs and dangerous chemicals with terahertz waves, and a powerful portable microscope for hunting down malaria.

All of the inventions are breakthroughs that prove the spirit of innovation is alive and strong in at least some corners of America.

Humanized mouse
The mouse with the human-like liver bridges a gap in the drug discovery pipeline between laboratory animals and human trials, Alice Chen, a biomedical engineer and graduate student in the Harvard-MIT Division of Health Sciences, told me on Tuesday.

Lemelson-MIT Program

Alice Chen invented a mouse with a human-like liver.

In the current pipeline, drugs are tested on animals such as lab mice before they cleared for human trials. The problem is that animals and humans are different in how their livers metabolize drugs. As a result, some lethal adverse interactions aren't caught before the human trails.

"We have some sad and preventable deaths," Chen said.

To help avoid those unnecessary deaths, Chen tissue-engineered a liver that breaks down drugs and responds to toxic drug products like a human liver and implanted it into a mouse. In these "humanized mice," she has found breakdown products of drugs that are normally only found in humans, proving the concept works.

Chen has also co-founded Sienna Labs, a biotechnology startup that has developed a class of medical pigments to enhance laser surgeries for skin disease.

"They are separate ventures, but in my mind they are connected in a way that's bringing a technology to a medical space that has a need for improved efficacy and improved safety," she said.

High-tech wheelchair
As Scott Daigle walked around the campus at the University of Illinois at Urbana Champaign, he watched how people who were in wheelchairs moved and decided that he could improve on the design. He did just that with his IntelliWheels, a manual wheelchair with an automatic gear shift.

University of Ilinois at Urbana-Champaign

Scott Daigle has invented a manual powered wheelchair with an automatic gear shift.

He told me that it is similar to the way people ride bicycles. "As they go up and down hills, shifting gears can make it much more ergonomically efficient. We use that same idea but in an automatic sense," he said.

Sensors on the chairs sense speed, how hard the users are pushing on the wheel rims, and the tilt of the slope. Based on those parameters, it shifts into the appropriate gear.

Daigle hopes the technology will cut down on the incidence and severity of shoulder pain experienced by many wheelchair users. "It can be almost an environmental barrier by having pain in your shoulders every push," he noted.

The technology entrepreneur is also developing other features for wheelchair users, including "hamster skis" that go on the small wheels in front of the chair and make getting around on snow covered sidewalks and roads easier.

Bomb detector
Some of the so-called naked body scanners at airports used to see through passengers clothes and determine if they are carrying things such as plastic explosives do this with terahertz waves, which occupy a segment of the electromagnetic spectrum between the infrared and microwave bands.

Rensselaer / Kris Qua

Benjamin Clough has invented a way to use sound waves to remotely detect terahertz waves.

Benjamin Clough, a graduate student in the department of electrical, computer and systems engineering at Rensselaer Polytechnic Institute uses them to do spectroscopy – that is getting chemical fingerprint of materials such as bombs.

A limitation of the technology, though, is that terahertz technology only works over distances of a few feet. At longer distances, naturally occurring moisture in the air absorbs the terahertz waves, weakening the signal. To overcome this limitation, Clough went on a beach vacation to Mexico.

That's where a discussion with his dad, a retired scientist with Sandia National Laboratory in New Mexico, helped him figure out a way to use soundwaves to remotely listen to terahertz waves.

To do this, he focuses two laser beams into the air to create small bursts of plasma, which in turn create terahertz pulses. Another pair of lasers is aimed near the target of interest to create a second plasma for detecting the terahertz pulses after they have interacted with the material.

This detection plasma produces acoustic waves as it ionizes the air.

"This is similar to a lightning and thunder situation," he told me. "You have a flash of light and a crack of thunder and it is this acoustic wave that I'm monitoring." That's because when the terahertaz interacts with this plasma, it influences the sound waves.

"We are taking that acoustic information that has the encoded terahertz information and we are able to retrieve the exact electric field profile of the terahertz pulse simply by listening to this event," he explained.

So far, the concept has been proven in the lab at distances of about 35 feet, making it, eventually, applicable for monitoring objects from a safe distance.

"You could envision several years down the road … a system where we could actually use this to detect an explosive material from 10, maybe 30 meters away," he said.

Portable microscope
For electrical engineering graduate student Guoan Zheng at the California Institute of Technology, his combination of a portable, high-resolution on-chip microscope and the computing power of smart phones should be enough to allow affordable detection of malaria in blood cells anywhere in the world.

EAS Communications Office at Caltech

Guoan Zheng invented a portable, on-chip microscope that provides high-resolution images.

The microscope doesn't use a lens or other optical components to magnify the blood cells, he explained to me. "Instead, we take a sequence of low resolution images of the cell (with a CMOS sensor) and then we process this sequence of low-resolution images to get a high-resolution image."

The on-chip microscope is about the size of a human thumbnail. The breakthrough means that a microscope as powerful as conventional lab microscope can be carried to remote parts of the world where bulky, expensive lab equipment isn't practical or possible.

This might help prevent some of the 1 million deaths attributed to malaria, a disease that is detected with a conventional microscope. "This whole process can be simplified using our little device," he said.

Zheng now plans to develop a smart phone application that can do the image processing for the microscope. "In the near future, there will be 1 billion smart phones out there," he noted. "So, if we can take advantage of that, the impact of our device will be much higher."

More stories about innovation:

• Eyeglass maker wins prize for inventors
• Creator of bomb detector wins prize
• Biotech pioneer wins invention prize
• Sound beam inventor takes the prize
• 7 award-winning innovations
• How inventive is the next generation

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

CollectSpace

The shuttle Enterprise, which was an aerodynamic test vehicle that never flew in space, gets a once-over at its display at the Smithsonian's National Air and Space Museum Udvar-Hazy Center, near Dulles International Airport in Virginia. Discovery is expected to take Enterprise's place after the retirement of the space shuttle fleet.

Last updated 12:12 p.m. ET March 9:

So what happens now that the shuttle Discovery has made its last landing? The most-flown spaceship in NASA's fleet will almost certainly end up on display at the Smithsonian — but not before it goes through a months-long round of technological taxidermy.

The first steps toward Discovery's destiny aren't all that unusual: NASA will put the orbiter through its routine post-flight maintenance, as if it were going back into space. But instead of prepping the space plane for its next mission, mechanics will give Discovery a major overhaul, turning the world's most complex flying machine into an unflyable museum artifact.

NASA has already figured out how to pull out all the stuff on Discovery that could pose a health hazard, ranging from fuel tanks and plumbing to thermal blankets that have soaked up toxic fumes for the past 26 years. The shuttle's main engines will be replaced with mockups built out of replicas and spare parts. The crew cabin will be spiffed up to look as if it's ready for flight, but in hidden areas, structural shells and skins will take the place of flight hardware.

When museumgoers get their first up-close peek at Discovery next year, they may have no idea that the space shuttle has been stripped down and rebuilt. "To the viewer, it will look as if the shuttle is intact," Robert Z. Pearlman, editor of CollectSpace website and a walking encyclopedia on the shuttle program, told me. "And for future generations of researchers, the process of removing all these materials has been very well documented."

Discovery's destiny is due to be announced officially on April 12, the 30th anniversary of the shuttle fleet's first spaceflight. Officially, Discovery's fate is a closely held secret. But the widespread assumption is that after putting nearly 150 million miles on its odometer, the senior space shuttle will go to the Udvar-Hazy Center, an annex of the Smithsonian's National Air and Space Museum that's right next to Dulles International Airport in Virginia.

Museum spokesman Brian Mullen insists that the Smithsonian is still "in the dark" about where Discovery will end up. "It's really up to NASA," he told me. For months, officials at the museum have been offering a statement so well-worn that it sounded as if Mullen had it memorized: "The museum is involved in discussions about transfer of the orbiter and other artifacts from the shuttle program. The final disposition of shuttle artifacts will be the decision of NASA."

But if NASA doesn't award Discovery to the Smithsonian on April 12, that would be a real shocker.

Sought-after shuttle
Discovery is the shuttle most sought after because it's the most flown and the oldest of the three orbiters remaining in the fleet (Columbia and Challenger, lost in 2003 and 1986, were older) — and also because it was involved in some of NASA's best-known missions, including the 1990 deployment of the Hubble Space Telescope and both of the "return to flight" missions in 1988 and 2005.

NASA offered it to the Smithsonian two years ago, but for a while it looked as if the Smithsonian would have to pass up the opportunity, due to the costs associated with getting a "free" space shuttle. NASA initially said any museum that was awarded a shuttle would have to come up with $42 million to reimburse the space agency for preparation and transport costs. That price tag was knocked down to $28.8 million, but the Smithsonian still reportedly balked. Congress finally stepped in with a legal provision last December saying that the Smithsonian would get a shuttle "at no or nominal cost" if NASA Administrator Charles Bolden thought it was an appropriate venue for display.

If Bolden gives his go-ahead on April 12 as expected, Discovery would take the place of the shuttle Enterprise, a craft that flew several aerodynamic tests in the '70s but never went into space. The Enterprise has been on display at the Udvar-Hazy Center since 2004. Giving Discovery to the Smithsonian means that Enterprise would be up for grabs, along with Endeavour and Atlantis, two other space shuttles that have yet to take their final turn in outer space.

"The Enterprise is an artifact under the Smithsonian's care," Mullen noted. "If we were lucky enough to get a flown orbiter, I'm sure NASA has a plan."

End of the shuttle scramble?
The disposition of Endeavour, Atlantis and presumably Enterprise is one of the hottest contests in the museum world. In all, 29 would-be exhibitors are vying to acquire a space shuttle, even though they'd have to pay the $28.8 million as well as the expense of providing a suitable exhibit space and getting the decommissioned orbiters spruced up for display. NASA wants to make sure the shuttles are better preserved than some high-profile space artifacts from the Apollo era. The prime example was a Saturn 5 rocket that was slowly rotting away at Johnson Space Center. Fortunately for space history buffs, the rocket was restored several years ago and moved to an enclosed, climate-controlled shelter, at a cost of $5 million.

Kennedy Space Center Visitor Complex

An artist's concept shows a space shuttle on display at the Kennedy Space Center Visitor Complex in Florida.

The most mentioned players in the shuttle scramble include:

• Kennedy Space Center Visitor Complex, which has drawn up plans for a $100 million, 64,000-square-foot exhibit where the shuttle would be displayed as if it were in flight, with its robotic arm extended to support an astronaut.
• Space Center Houston, which has proposed the construction of a 53,000-square-foot hangar at the visitor center for Johnson Space Center in Texas.
• The National Museum of the U.S. Air Force in Dayton, Ohio, which is planning to add a 200,000-square-foot exhibit hall to its grounds. The Dayton museum is particularly interested in Atlantis because of that shuttle's past role in Air Force space missions.
• Seattle's Museum of Flight, which has started work on a $12 million, 15,500-square-foot "Human Space Flight Gallery" that would be available to showcase a shuttle.
• The Intrepid Sea, Air and Space Museum, a dockside facility in Manhattan that has been built alongside the aircraft carrier Intrepid.

It's not yet exactly clear yet how much time would pass between a shuttle's last flight and its handover to one of the museums, but Pearlman said NASA would like to have the shuttles in a position to go to their future homes as little as six months after their final flights. Realistically, the job may take longer than that. "It looks like it will take at least a year for preparations," Mullen told me.

NASA spokesman Michael Curie recently said in an e-mail that the space agency was looking into scenarios that would require the space agency to hang onto a shuttle for longer than expected after retirement. "As a what-if budget exercise, we are looking at what it would cost if a recipient was not ready to take an orbiter right away, and if we wanted to keep an orbiter in long-term storage for potential engineering analysis," he wrote.

United Space Alliance, the contractor that manages most aspects of the shuttle program on NASA's behalf, has proposed using Endeavour and Atlantis in a commercial operation to resupply the International Space Station. That would short-circuit NASA's plan for sending those two shuttles to the museums anytime soon. However, the USA proposal doesn't seem to have a high chance of gaining NASA's support, particularly in view of the Bolden's plan for an April 12 announcement on the shuttles' fate.

The final, final journey
When NASA has finished decommissioning a shuttle, it would be loaded atop the modified Boeing 747 jet that serves as NASA's carrier airplane and flown to the airport that's nearest to the orbiter's destination, Pearlman said. Cranes would be used to lift the shuttle off the plane, and then the exhibitor would take it from there.

If the Kennedy Space Center Visitor Complex gets one of the shuttles, the job won't require a plane trip, Pearlman noted. And if the Smithsonian gets Discovery as expected, the shuttle would be hoisted off the carrier plane and rolled along Dulles' runway to the Udvar-Hazy Center. The same plane could conceivably give the Enterprise a piggyback flight from Dulles to its new destination.

"While all the other orbiters are seeing the end of their flight careers, Enterprise is getting a bit of a reprieve. It'll have one last carry on the top of a 747," Pearlman joked.

You might think that Pearlman, an enthusiast for space history and memorabilia, would be over the moon at the prospect of seeing Discovery up close in a museum. But that's not the case.

"I think everyone would love to see the orbiters continue flying," he said. "I'd much rather see Discovery go on and fly another 39 flights. I just don't think that at this point, with our national priorities ... well, I don't see that as a very likely possibility."

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

Stan Honda / AFP - Getty Images

The International Space Station and the shuttle Discovery streak through the sky above New York's Central Park on Monday. The two spacecraft appear as stars moving through the evening sky; the long streak is an effect of the camera time exposure. Discovery's final space mission ends Wednesday.

The Discovery farewell tour continues with more cool views from space, including a view you might see just by stepping outside and looking up at the right time.

Now that the shuttle Discovery has undocked from the International Space Station for the last time, the two spacecraft are growing more distant with each orbit. But if you're in the right locale, they can still be seen in close succession Tuesday night, passing overhead about a minute or two apart. Schedules for the flyovers are available from several websites:

• NASA lists sighting opportunities for cities all over the world. The easiest way to get a schedule is to click through listing of countries and cities to find the place closest to your location. The sighting location is expressed in degrees above the horizon, where 10 degrees is roughly the width of your outstretched fist held out at arm's length. So if the listing for New York City tells you to look to the west, 29 degrees above the horizon, at 7:24 p.m., you'd want to stretch your arm westward and measure out about three fist-lengths above the horizon. Discovery would show up first as a faint star, moving toward the south. The brighter space station would follow a similar track about a minute later.
• The Heavens Above website also charts the movements of the shuttle and space station across the sky, based on the user preferences you provide when you register.
• SpaceWeather.com also lists sighting opportunities, based either on ZIP code or non-U.S. location. Discovery isn't listed separately in these viewing tables, but if you subtract a minute or two from the time for seeing the space station, you'll probably be in good stead for seeing the shuttle as well.

Unfortunately, there are some places where folks won't be able to catch the show, either because the orbital track doesn't allow the shuttle and station to catch the glint of the sun at the right time, or because the skies aren't clear and dark. (Curse you, cloudy Seattle weather!) But even if you're in that situation, all is not lost: You can still enjoy the views you can get on your computer.

Thierry Legault / Patrick Vantuyne

This 3-D image of the space shuttle Discovery docked to the International Space Station is based on photos captured by a telescope set up in Germany. To get the 3-D effect, look closely at the photo cross-eyed. At the proper distance, the left and right images will blend to produce a sense of perspective.

For instance, take a look at Patrick Vantuyne's 3-D image of the docked shuttle and station. This amazing view was captured by French photographer Thierry Legault earlier in the mission, using a telescope that he pointed up from an opportune viewing spot in Germany. Vantuyne, who hails from Belgium, took Legault's images and created a version that can give you a sense of depth when you look at it cross-eyed.

Usually I have a problem with cross-eyed 3-D imagery — I prefer the kind that you see through cheap red-blue glasses — but I was able to get the three-dimensional effect out of this one. I hope you can as well.

Still more awesome views should come out of the "fly-around" that Discovery made just after undocking from the space station. These maneuvers produce shots of the station as seen from the shuttle, as well as the shuttle as seen from the station.

This YouTube video provides a sampling of what the space station's crew saw as Discovery made its final station inspection today (plus Captain Kirk's not-to-be-missed wake-up call). 

Update for 3:30 p.m. ET March 8: As promised, here's a beauty shot of the International Space Station as seen from Discovery during its fly-around on Monday:

NASA

The International Space Station is backdropped against Earth in a picture taken from the shuttle Discovery.

We'll have more of these high-definition shots in a follow-up on Photoblog.

In the meantime, check out our Space section for the latest on Discovery's final mission, and our Space Gallery for the most recent installment of "Month in Space Pictures" slideshow. 

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

Higher gas prices are posted at a Chevron gas station in San Francisco, Friday, March 4, 2011. Gasoline prices have shot up an average of 35 cents per gallon since an uprising in Libya began in mid-February.

Scientists who engineer microbes to efficiently produce biofuels from plants and algae are busy reporting breakthroughs that could wean us from fossil fuels – offering a glimmer of hope to consumers eyeing gas prices skyrocket.

In one breakthrough, a microbe has been genetically engineered to produce isobutanol, a gasoline-like fuel, directly from cellulose.

"That's the first time cellulose has directly been used to produce four-carbon alcohols," James Liao, vice chair of chemical and biomolecluar engineering at the University of California, Los Angeles, told me today.

Cellulose feedstock
Cellulose such as switchgrass and the leaves and stalks of corn, is a more abundant and cheaper feedstock for biofuel production than corn and sugarcane, but is difficult to breakdown to the sugars that microbes convert into alcohol fuels.

For example, some strains of the microbe Clostridium produce butanol, but they don't do so directly from cellulose. It first has to be broken down into sugars. Other species of Clostridium digest cellulose, but don't produce butanol, Liao explained.

"We designed a new pathway" that allows Colstridium to produce isobutanol directly from cellulose and transferred that pathway into the Clostridium celluloyticum, Liao said. This strain naturally digests cellulose. Their genetic manipulation allows it to produce isobutanol as well.

In addition, isobutanol is a higher grade of alcohol than ethanol, which is primarily produced today from corn. Most cars on the road can run on blends of gasoline with up to 10 percent ethanol.

"Unlike ethanol, isobutanol can be blended at any ratio of gasoline and should eliminate the need for dedicated infrastructure in tanks or vehicles," Liao added in a press release about the breakthrough. "Plus, it may be possible to use isobutanol directly in current engines without modification."

The research was published online in the journal Applied and Environmemental Microbiology.

Butanol production
The promise of butanol as a biofuel is spurring several researchers to genetically optimize microbes to produce it. Researchers at the University of California at Berkeley reported March 2 a genetically engineered strain of E. coli that produces n-butanol at rate that is 10 times better than competing systems.

The researchers are interested in using E. coli, which doesn't naturally produce butanol, because it is easier to work with and scale up the process for industrial production of biofuel.

Unlike the new microbe, however, the E. coli currently uses straight sugar to produce the fuel. More research will be required to figure out how to get the sugar from biomass, Michelle Chang, the Berkeley chemist leading the research effort, told me.

Liao's group at UCLA is also at work on engineering E. coli to produce n-butanol and have achieved 15 to grams per liter from sugar. Their paper will be published online later this week.

Fuel from proteins
In addition, Liao's team published research on Sunday in the journal Nature Biotechnology describing a method for producing biofuels where "we use proteins instead of cellulose, sugars, or lipids," he told me.

To do this, the team changed the metabolic pathways in E. coli so that they efficiently remove nitrogen from groups of amino acids — the building blocks of proteins — to produce alcohols, which are converted to biofuels.

The team argues that proteins are attractive molecules to turn into fuels because proteins are produced as byproducts from current industrial processes and because they can be made more abundant than carbohydrates from sugars and cellulose and lipids from vegetable oil.

Until now, however, no one knew how to turn them into fuel.

"Microorganisms tend to use proteins to build their own proteins instead of converting them to other compounds," Yi-xin Huo, a UCLA postdoctoral researcher and lead author of the study, said in a news release.

Liao's team created an artificial metabolic system to dump reduced nitrogen out of cells and tricked the cells to degrade proteins without utilizing them for growth. Proteins contain both ammonia and carbon; Liao's team took away the ammonia and recycled it back for the growth of the algae they worked with.

"Today, nitrogen fertilizers used in agriculture and biofuel production have become a major threat to many of the world's ecosystems, and the nitrogen-containing residuals in biofuel production can eventually turn into nitrous oxide, which is about 300 times worse than CO2 as a greenhouse gas," Liao added in the news release.

"Our strategy effectively recycles nitrogen back to the biofuel production process, thus approaching nitrogen neutrality."

The researchers are now working on scaling up the technology.

More stories on biofuels:

• Bacteria turned into biofuel factories
• W2 begins to construct biobutanol reactor
• Bacteria rebuilt to make oil
• Mutant bacteria + polyester = more biofuel
• The race to replace gasoline
• Yeast is rising as a biofuel booster
• Scientists look to tobacco as a potential biofuel

R. Hoover / Journal of Cosmology

An image created using a field-emission scanning electron microscope shows a coiled filament that was found within a carbonaceous meteorite. The scale bar indicates a length of 20 microns.

Last updated 7 p.m. ET March 8:

A NASA researcher's claim that organisms from outer space have been found within a rare class of meteorites certainly sparked a lot of comments over the weekend, from experts on astrobiology and microbiology as well as from the public at large. Some of the commentators have been pretty scathing. David Morrison, senior scientist for the NASA Astrobiology Institute, told me in an e-mail that the paper really should have been published on April Fool's Day. Pharyngula's P.Z. Myers, a biologist at the University of Minnesota at Morris, said "this work is garbage" and voiced surprise that anyone was taking it seriously.

Now the Journal of Cosmology, which published the much-debated paper by NASA biologist Richard Hoover, has added a batch of commentaries from a variety of researchers and others. Here are some of the folks in the journal's lineup:

• Cody Youngbull of the University of Arizona's Biodesign Institute notes that Hoover's claims have "gone viral, with major media news sources and Internet blogs all carrying reports of this story. And so too the experts, for whom this information is not new, who have been monitoring the accounts of fossils in these same meteorites since 1961, have something to get excited about. ... This is because, while the elemental and mineral composition data remains identical to prior accepted reports, the morphological data far exceeds anything yet shown on the subject."
• Harrison Schmitt, the Apollo 17 scientist-astronaut who went from walking on the moon to serving in the U.S. Senate and who is now a researcher at the University of Wisconsin at Madison, says he can't pass judgment on the research itself. Instead, he wonders "why many do not seem to want life to have originated independently on Earth. ... We just have to figure out how it all happened."
• Patrick Godon, an astrophysicist at Villanova University, says Hoover "presents firm evidence" that fossil microbes are embedded within the meteorites, but he says it's "debatable" whether the microbes came from Earth or from somewhere else in outer space.
• Elena Pikuta, a microbiologist from the University of Alabama at Huntsville who has collaborated with Hoover, says the study "represents a sensational discovery which will have the potential to change our understanding on the origin of biosphere." The findings from the meteorites were "analyzed and interpreted according to the current standards in science using highly sensitive laboratory techniques," she says.
• Tulane University physicist Frank Tipler, author of the controversial book "The Physics of Immortality," says that "although Hoover has done as much as is possible with his small sample, we cannot yet conclude that he has indeed seen fossil cyanobacteria."

The journal may have decided against immediately publishing some of the responses it received, based on the missing numbers in the order of the commentaries. As of late today, No. 15 out of 21 was still missing  — and No. 11, attributed to Cardiff University astrobiologist Chandra Wickramasinghe and carrying the subtitle "A Vindication of Panspermia," wasn't yet displayed on the page.

Generally speaking, the journal's commentaries don't provide the kind of hard-hitting criticism that some of the better-known outside experts on microbiology have been voicing in other forums. But they do suggest that Hoover's claims will continue to be debated rather than going immediately into the trash can.

Update for 11 a.m. ET: In a statement distributed by the SpaceRef website, one of NASA's top scientists says the space agency does not support Hoover's findings. Here's the word from Paul Hertz, chief scientist of the Science Mission Directorate at NASA Headquarters in Washington:

"NASA is a scientific and technical agency committed to a culture of openness with the media and public. While we value the free exchange of ideas, data and information as part of scientific and technical inquiry, NASA cannot stand behind or support a scientific claim unless it has been peer-reviewed or thoroughly examined by other qualified experts. This paper was submitted in 2007 to the International Journal of Astrobiology. However, the peer review process was not completed for that submission. NASA also was unaware of the recent submission of the paper to the Journal of Cosmology or of the paper's subsequent publication. Additional questions should be directed to the author of the paper."

Meanwhile, Universe Today's Nancy Atkinson got in touch with Chris McKay, an astrobiologist at NASA's Ames Research Center. Here's a sampling from McKay's comments:

"The implication of these results is that the meteorite hosted a liquid water environment in contact with sunlight and high oxygen. ... Richard Hoover is a careful and accomplished microscopist so there is every reason to believe that the structures he sees are present and are not due to contamination. If these structures had been reported from sediments from a lake bottom there would be no question that they were classified correctly as biological remains."

McKay also acknowledged, however, that the structures could turn out to be "chance shapes" that just happen to look like pieces of an organism. That kind of interpretation was put forward to explain the "nanofossils" seen in a meteorite from Mars back in 1996. Moreover, if the structures do turn out to be cyanobacteria, and they're not contaminants, it'd be hard to explain in biological terms how they could survive on a meteorite in space.

Update for 11:30 a.m. ET: One of the questions that has come up is, "If they really did find alien life, why isn't this research being published by one of the big scientific journals, such as Science or Nature, rather than some little online publication that's on the brink of going out of business?" Lana Tao, managing editor for the Journal of Cosmology, addressed that question in an e-mailed statement:

"The Journal of Cosmology has received e-mails asking why Dr. Hoover's paper was not published in Science or Nature. We are aware that individuals who may or may not be associated with these publications are posting ad hominem attacks, which essentially wish the public to believe that if Dr. Hoover's article was really important it would have been published by these other journals. These are tantamount to schoolyard taunts by jealous children.

"1) First, Dr. Hoover's article was an original contribution and had not been submitted to these two periodicals.

"2) Secondly, both Science and Nature have a nasty history of rejecting extremely important papers, some of which later earned the author's a Noble Prize [sic]. Use Google keywords search for a wealth of info.  Nature magazine admits to this, though they put a positive spin on these rejections.

http://www.nature.com/nature/journal/v425/n6959/full/425645a.html

"3) Editors at Science have been accused of using the Bible to make editorial decisions by scientists such as Dr. Gil Levin (who devised the famous NASA Viking Mars Experiments). 

"4) It is a matter of public record that the organization which publishes science magazine have engaged in illegal anti-competitive practices designed to harm the Journal of Cosmology. The continuing success of JOC poses a competitive threat to their business model. We should not be surprised their 'hand puppets' are complaining that JOC published this article, and not them.

"5) Science and Nature are in the business of making money. The Journal of Cosmology is free, open access, and is in the business of promoting science.

"6) Science and Nature protect the status quo, and have a history of rejecting great papers.

"7) In less than 2 years, the Journal of Cosmology has become one of the top online science journals, with nearly a million hits for January. Our mission is to advance science.

"8) The ad hominem attacks and complaints by those say Dr. Hoover's article should have been published in these other periodicals, and not JOC, are just sour grapes and should not be taken seriously.

"9) We have repeatedly offered to publish critical commentary. We are still waiting."

Update for noon ET: Bad Astronomy's Phil Plait says he's come to the conclusion that "Hoover's claims are wrong," based on many of the factors we've been talking about (criticism of methods from microbiologists, questions about the venue for publication, scant peer review and lack of NASA support, etc.). One of the more interesting angles comes from his e-mail exchange with Penny Boston, an astrobiologist and geologist at New Mexico Tech who is an expert on extremophiles in caves. Her view is that it's virtually impossible to rule out the possibility of earthly contamination just by looking at something in a rock sample, due to the ubiquity of life on Earth. Here's a sample quote:

"Rocks, even the most high density materials, are prone to microfractures. Microorganisms are notoriously splendid at working their way into incredibly minute microfractures. ...

"Showing that the bug that you have actually is NOT a contaminant organism that made its way into a meteorite is a practically unsolvable problem. If you turn up an organism whose chemistry, way of coding information, or something else (besides morphology) indicates that it is significantly (and I MEAN significantly) different from anything that has ever been seen on Earth, THEN you might have a chance of proving this. Pictures of tube shaped structures don’t do it."

Update for 2:40 p.m. ET: Carl Pilcher, director of the NASA Astrobiology Institute, told The Associated Press that the structures seen in the meteorite are most likely earthly contamination. He turned thumbs down on Hoover's claim that they were extraterrestrial organisms:

"There has been no one in the scientific community, certainly no one in the meteorite analysis community, that has supported these conclusions. The simplest explanation for Mr. Hoover's measurements is that he's measuring microbes from Earth. They're contamination."

Update for 4:45 p.m. ET: In a comment appended to Keith Cowing's posting about the study on NASA Watch, Rocco Mancinelli of the Bay Area Environmental Research Institute takes issue with the NASA statement that "the peer review process was not completed" when a paper by Hoover was submitted for publication in the International Journal of Astrobiology in 2007. "The paper was rejected, after peer review," said Mancinelli, who is listed as an associate editor of that journal. (Mancinelli also sent in critical comments that were included in my previous roundup on the "meteorite life" study.)

Update for 9:25 p.m. ET: There's been a lot of back and forth over whether Hoover has claimed to have a Ph.D. NASA Watch's Keith Cowing has put a lot of effort into this — and determined from NASA that he doesn't have a Ph.D., even though the Journal of Cosmology paper lists him as having one. Jennifer Lewter, a teacher who says she's a "big fan of Dr. Hoover's," indicates in her blog postings that he has two honorary doctorates.

Meanwhile, the journal's managing editor, Lana Tao, said in an e-mail that 21 commentaries on Hoover's paper had been received and that all were published, even though two (Nos. 11 and 15) still seemed to be missing at the end of the day. One of the late entries, from Oxford's Martin Brasier (No. 9) cast doubts on Hoover's results. "These samples have been sitting around in laboratories for between 205 and 73 years," he wrote. "It is well known that microbial contaminants can penetrate deep into such rocks, even during storage. The null hypothesis, therefore, is that many of these objects ... may be prokaryotic contaminants." (Cyanobacteria qualify as prokaryotic organisms.)

Tao also fired back once more at the journal's critics, insisting that Hoover's paper went through adequate peer review. Here's a quote from the e-mail:

"As every editor and guest editor will attest, all articles are subjected to peer review. We reject over 30 percent of invited papers and over 70 percent of those which are not invited. Every editor, and guest editor, has had their work subjected to peer review, and every editor has been required to revise their articles after peer review. Even the executive editors have been required to revise their papers after peer review.  We believe in peer review.

"Peer review provides wonderful feedback which can help make a paper better, or which can explain why the paper is hopeless and must be rejected. However, we do not reject great papers because we disagree with them as is the habit of other periodicals.

"Dr. Hoover's paper was received in November. It was subjected to repeated reviews and underwent one significant revision.

"We have published every commentary received, 21 so far. The vast majority support Dr. Hoover's findings.

"The choice is simple: Scientific discourse vs psychosis. Hysteria and lies do not constitute scientific doubt. They are calls for medication."

Update for 7 p.m. ET March 8: Now for the postmortems: Two more e-mails went out from Tao overnight. One was addressed to Paul Hertz, the NASA scientist who implied that the agency could not "stand behind or support" Hoover's claims because they had not been sufficiently peer-reviewed. In the message, which was copied to numerous others including yours truly, Tao said "we will file a formal complaint with NASA regarding your unprofessional, dishonest conduct." She said "over 30 NASA scientists have published with the Journal of Cosmology" and insisted that the articles "underwent rigorous peer review."

In another e-mail message, Tao thanked members of the media "for covering this important story and bringing attention to Richard Hoover's discoveries." She said the journal's owners accepted a buyout offer two weeks ago, before last weekend's flap. "The selling of JOC also means a new managing editor," she wrote. "Therefore with this thank you, I also get to say ... goodbye!"

Today, Columbia Journalism Review's Curtis Brainard recapped the whole saga of the microbes in the meteorite ... and the media ... in a posting to The Observatory blog.  "Anything having to do with extraterrestrials has a way of creating a media frenzy," Brainard observed. "But reporters have obviously learned from frenzies past."

I'm definitely feeling frenzied out, but Tao's earlier reference to Gil Levin's claims about the Viking experiments has reminded me to add that issue to the list of controversial astrobiology results:

• Did Viking find life on Mars ...
• ... Or did Viking kill life on Mars?
• Definition of life: Arsenic debate just won't die
• Strange find on Titan sparks chatter about life
• Mars methane mystery: What's making the gas?
• Meteorite study revives debate over life on Mars
• Search for alien life may take giant leap forward

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

R. Hoover / Journal of Cosmology

A field-emission scanning electron micrograph shows one of the filaments that was found in the Ivuna CI1 carbonaceous meteorite. The image includes labels for data about elemental composition. The bar at lower left shows the 1-micron scale. The filament looks similar to those seen in earthly cyanobacteria.

Last updated 4:20 p.m. ET March 6:

Are there traces of ancient bacteria trapped inside meteorites that fell to Earth decades ago? You can add that question to the list of unresolved issues surrounding the search for life beyond Earth, thanks to a just-published study by a NASA researcher.

The new study, published in the Journal of Cosmology, focuses on structures that look like the filaments that biologists typically see on micro-organisms known as cyanobacteria. Richard Hoover, an astrobiologist at NASA's Marshall Space Flight Center in Alabama, found the filamentary structures inside samples of meteorites that are thought to date back to the solar system's beginnings, more than 4 billion years ago.

If the structures are confirmed to be of biological but unearthly origin, that would serve as fresh evidence that life can make its way through outer space and "seed" planets, including our own, Hoover told me today.

"Life may have a wider planetary distribution than simply being limited to the planet Earth," he said. In the paper, Hoover said the evidence suggests that microbial life could well exist on comets or icy worlds such as Europa or Enceladus.

Most astrobiologists might be willing to go along with that broad conclusion. However, Hoover's specific claims could well end up in the same sort of limbo that surrounds the claims made 15 years ago about microfossils inside a meteorite from Mars.

The initial evidence was the subject of dramatic news conferences and huge headlines, but as time went on, doubts about the findings grew. Today, few astrobiologists see the Mars meteorite as containing any conclusive evidence for the existence of past or present Martian life.

Cautious and skeptical reactions
"This may turn out to be another one of those cases where it's controversial but remains unproven," Seth Shostak, senior astronomer at the California-based SETI Institute, told me today.

Shostak said Hoover's findings would be "important, if true." But he noted that the research paper relied on a highly technical interpretation of electron microscope images and chemical analyses. "Is it true? I'm not qualified to say that," Shostak said.

The Journal of Cosmology's editor-in-chief, Rudy Schild of the Harvard-Smithsonian Center for Astrophysics, said in a note accompanying Hoover's study that 100 experts were invited to critique the research, and that any commentaries would be published beginning Monday. The overall tone of the commentaries is likely to be skeptical: Lynn Rothschild, an astrobiologist at NASA's Ames Research Center in California, said many biologists were "very concerned" about the claims.

More than one expert wondered why the research merited any news coverage at all.

"Many scientists have examined thousands of meteorites in detail over the past 50 years without finding any evidence of fossil life," David Morrison, senior scientist at the NASA Astrobiology Institute at Ames Research Center, told me in an e-mail. "Further, we know a great deal about the conditions on the parent objects of the meteorites, which (not counting the few meteorites from the moon and Mars) were rather small, not at all like planets.

"I would therefore invoke Carl Sagan's famous advice that extraordinary claims require extraordinary evidence. At a bare minimum this would require publication in a prestigious peer-refereed scientific journal — which this is not. Cyanobacteria on a small airless world sounds like a joke. Perhaps the publication came out too soon; more appropriate would have been on April 1," Morrison said.

Questions about origin
The debate over the validity of Hoover's claims is likely to concentrate over whether the filamentary structures are truly biological in origin, and if so, whether they're the result of earthly contamination.

Hoover said that the filaments, which can measure more than 20 microns long, are of the right size and shape to match the characteristic structures seen in types of cyanobacteria.

"Because of the fact that they are so large and so complex, and many of them have specialized cells, these cyanobacteria can be identified — sometimes to genus and species — just on the basis of certain specialzed cells," he explained. One of the structures found in the meteorites is similar to that seen in the giant bacterium known as Titanospirillum velox, for example.

If the structures are so similar to those seen in earthly organisms, could that be because they're actually the traces of cyanobacteria that found their way into the meteorite? Hoover argues that they're not the result of contamination. He said that cyanobacteria are generally found in aquatic environments, but the meteorites are made of stuff that falls apart when exposed to liquid water. He also said chemical tests on the filaments could find no evidence of nitrogen, which should have been present if earthly cyanobacteria infiltrated the meteorites. One of the meteorites, for example, is known to have fallen to Earth in France in 1864.

"The inability to detect nitrogen in the filaments indicates that they are ancient, and since the meteorite came to Earth in 1864, that indicates that they were in the meteorite when it fell," Hoover said.

Previous analyses of the meteorites' chemical composition have concluded that they were formed during the solar system's earliest epoch, perhaps as comets. But Hoover said that doesn't necessarily mean the structures were present from the very beginning. They could have been picked up from debris that was knocked into space by cosmic impacts. They could even have come from Earth itself, as the result of a meteor blast that occurred millions or billions of years ago.

"That's absolutely possible," Hoover acknowledged. "I have no reason to say I could rule that out."

Hoover has made provocative claims before, and he fully expects that others will contest his conclusions this time as well. "I can only make my observations, based on the scientific results that I see," he told me.

What do you think? Is this a significant advance for the study of life beyond Earth, or a blip hardly worth writing about? Feel free to weigh in with your comments below.

Update for 6 p.m. ET: Rocco Mancinelli, senior research scientist at the Bay Area Environmental Research Institute, weighed in with this e-mailed critique of Hoover's paper:

"As a microbiologist who has looked at thousands of microbes through a microscope, and done some of my own electron microscopy, I see no convincing evidence that these particles are of biological origin.  

"The techniques used may not have been appropriate for these types of analyses. It is stated that the implements were flame-sterilized, with no details of how this was performed.  Were the implements placed in the flame of a Bunsen burner? If so, sometimes soot can get on them at the microscopic level. The usual procedure for flame sterilization is to dip the implements in ethanol then burn the ethanol off. Yet, these would be inappropriate for this type of analysis. You need to have everything clean and then bake at 550 degrees C overnight.  These missing details would cause me to question not just about the photos, but the elemental analyses as well.  I am also disturbed about the lack of nitrogen. There should be more. There are many technical flaws in this paper."

Update for 10:50 p.m. ET: Dale Andersen, principal investigator at the Carl Sagan Center for the Study of Life in the Universe at the SETI Institute, sent his detailed reaction in an e-mail:

"I would be absolutely thrilled to see this story verified, and it would be even more exciting if we found evidence of life that was quite different from terrestrial life — say, for example, its genetic coding used different base pairs than Earth life. That would imply not just evidence of life from beyond our planet, but would demonstrate an independent genesis of life, something that would be absolutely astonishing.

"That said, one needs to look at this paper with a lot of caution, particularly with [the Mars meteorite] ALH 84001 in mind. That was a great story and generated a wonderful debate that continues even today — regardless of the outcome, I would say it was a success story. The best of the best have worked on that meteorite and tried in vain to prove or disprove the original thesis that ALH 84001 holds evidence of life from the planet Mars. While I think it's fair to say that the general scientific consensus is that McKay et al. [the researchers who did the Mars meteorite study] did not provide unambiguous evidence of extraterrestrial life, the process that accompanied the effort throughout was well worth the effort. The scientific community was compelled to think in new ways and to find better tools and methods to examine the evidence. This resulted in technological advances and a much better understanding of how to approach the problem and finding its answer. And the public was very engaged throughout, which was a good thing. I hope there is long-term, strong support for NASA's Exobiology program and that NASA is allowed to continue the search for a better understanding of the origin, evolution and distribution of life in the universe; it's a goal worthy of support.

"With respect to Richard Hoover's claims about finding evidence of life within the samples of meteorites he has observed, I think he has a very high bar to clear before this story is accepted by the scientific community.  It should also be noted that Richard has published this thesis previously (e.g., in 2004: "Perspectives in Astrobiology" (NATO Science Series: Life and Behavioural Sciences, Vol. 366) [Hardcover] Richard B. Hoover (Editor), Aleksei Iurevich Rozanov (Editor), Roland Paepe (Editor)), and the ideas were not well-received nor did they gain traction within the scientific community.

"Peer review will include the examination of his and other scientists’ data and logic, and not until that has occurred will we see how the story unfolds. Occam's razor will eventually be used to slice and dice the carbonaceous chondrites used by Richard to present his evidence. Is it more likely that upon looking into the interior of a meteorite collected on Earth and finding photosynthetic cyanobacteria, which on Earth are usually found in water or wet sediments, their presence is due to contamination from terrestrial sources or that it formed inside the parent body of comet or asteroid in deep space? There will be many other possibilities to rule out before one arrives at the extraterrestrial answer.

"I hope the public does not assume that this story is a certainty — it clearly is not, at least not at this point.  Mostly, I hope the general public is able to learn more about the scientific process and the use of critical thinking skills to arrive at the truth and are not confused by an endless parade of silly articles that neither enlighten nor inform. Let the debate begin.

"A side note: I am not an expert with respect to meteorites. It would be very useful to get some of the ALH 84001 folks to weigh in on Richard’s findings, techniques, histories of the meteorites used (where collected, handling), logic etc. And while it may be OK to express healthy skepticism in public forums — meetings such as AbSciCon, AGU, AAAS, etc. and the scientific literature are the places to really rebut and critique the body of work presented — the scientific process should be the judge. Perhaps that is the real story here.  Let the facts demonstrate the truth."

I e-mailed an inquiry to David McKay, one of the leaders of the ALH 84001 research team at NASA's Johnson Space Center, even before Andersen mentioned the idea — and I'll report back if I hear anything.

Update for 3 p.m. ET March 6: More critical commentaries are coming in, from Pharyngula's P.Z. Myers as well as from Rosie Redfield, the microbiologist at the University of British Columbia who blew the whistle as well on the "arsenic life" research that made such a splash last December. Here's a link roundup:

• Pharyngula: Did scientists discover bacteria in meteorites?
• RRResearch: Is this claim of bacteria in meteorite any better than 1996's?
• NASA Watch: MSFC astrobiologist claims he's found life in a meteorite
• Dot Earth at N.Y. Times: NASA scientist sees signs of life in meteorites
• NPR: Has evidence of alien life been found in meteorites?
• Discovery News: Has evidence for alien life been found?
• Bad Astronomy: Has life been found in a meteorite?

Update for 4:20 p.m. ET March 6: Rudy Schild, the astrophysicist at the Harvard-Smithsonian Center for Astrophysics who is also the editor-in-chief of the Journal of Cosmology, sent this open letter via e-mail today:

"The Journal of Cosmology had issued a personal invitation to 100 scientists, and a general invitation to over 5,000 members of the scientific community, inviting critical commentary on Dr. Hoover's landmark, paradigm shattering paper.  All were given access to a PDF containing a preprint of Dr. Hoover's article.

"Within hours of making it available, it was downloaded over 1,400 times.

"After issuing an open invitation for scientists to search for flaws and to report them in a scientific forum, as of March 6, the Journal of Cosmology has received 12 commentaries.

"Five detail what could best be described as minor quibbles. One offers an alternative explanation as to the origin of these fossils but does not dispute the evidence. We will publish all commentaries so far received, this evening.

"It is natural to have doubt. Skepticism is the nature of science. Debate is healthy and is good for science. We are frankly amazed that we have not received an avalanche of critical commentaries.

"Perhaps the reaction could be described as 'stunned silence'?

"As to those who post insults on various websites, this is not to be taken seriously.

"On the other hand, Dr. Hoover's article, and the lack of scholarly, critical dispute, may be an indication of a paradigm shift; similar to the realization that Earth was not flat nor the center of the Universe. What I mean is: Most scientists and perhaps most of the public realize life must be everywhere throughout the cosmos and not just confined to Earth, and Dr. Hoover's paper simply confirms what most already suspect.

"This may also account for why the over 150 news articles and blogs so far published (with the exception of MSNBC), the response has been generally favorable or positive in nature.

"The inability, so far, of the scientific community to find and present any major flaws in a scientific forum and to submit and publish them in a scientific Journal which has invited critical commentary, speaks for itself.

"However, the jury is still out.  Our deadline for receipt of scientific commentaries is Monday, the 7th.   We will extend that deadline.

"The Journal of Cosmology will publish critical commentary. We encourage it. We ask the media to encourage the scientific community to send us critical commentary.

"However, so far, the verdict appears to be: We are not alone."

Earlier, Schild forwarded some additional reactions to Hoover's paper. Here is a quote attributed to Carl Gibson of the Center for Astrophysics and Space Sciences at Scripps Institute and the University of California at San Diego:

"Dr. Hoover has provided the world with extraordinary evidence to back up extraordinary claims. This discovery completely changes our perspective of the nature of life and our place in the universe. The world will never be the same."

Here's a quote from Chandra Wickramasinghe, director of the Astrobiology Centre at Cardiff University, who has also stirred up controversy for his views about life from space:

" Dr. Hoover has provided the world with decisive evidence that we are all aliens. Life is a truly cosmic phenomenon. ... We believe Dr. Hoover's evidence, coupled with other findings and recent genetic studies, indicates life has a genetic ancestry which leads over 10 billion years back in time. Some of these life forms were delivered to Earth, in comets."

I've started up a new item with further reaction, from the Journal of Cosmology's commentaries as well as other sources. 

More controversies in astrobiology:

• Definition of life: Arsenic debate just won't die
• Strange find on Titan sparks chatter about life
• Mars methane mystery: What's making the gas?
• Meteorite study revives debate over life on Mars
• Search for alien life may take giant leap forward

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto."