Discovery Channel

Click for video: A scene from the first installment of the Discovery Channel's "Human Body" series shows how bones and muscles work together for survival during a tornado. Click on the image to watch a video clip.

Did you know that your bones are stronger, pound for pound, than concrete? Or that in an emergency, your muscles could be three times stronger than you think they are? "Human Body: Pushing the Limits," a TV series premiering Sunday on the Discovery Channel, delivers those insights and more by analyzing the extraordinary feats of ordinary people, with virtual X-ray vision.

"The concept for the series came from our desire to, if you will, bring to knowledge of the human body what 'Planet Earth' brings to the world around us," executive producer John Grassie told me today. "So in many respects, this is the 'Planet Earth' of the human body."

That's a pretty high bar to reach, considering how sumptuous the panoramic shots were in that earlier TV series. The scale is much different for "Human Body," which focuses on the capabilities inside our skin rather than the wonders of the world outside.

The first program focuses on the usually untapped strengths of our skeleton and muscles, as well as our cartilage and energy storage system. On one level, we're watching the kinds of survival stories you often see on "Dateline NBC": a man who survives being sucked up by a tornado and thrown back down to earth ... a mountain climber who tosses a 1,200-pound rock off his chest ... a police officer who outruns a firestorm ... a swimmer who loses 14 pounds as he crosses the English Channel.

What sets "Human Body" apart is the inside view: computer graphics that reveal the workings of our hinged ribcages, our triple-teaming muscle fibers, our stronger-than-steel bands of cartilage and a fat layer that stores up the energy we need to cope with a crisis.

""It's not a question of the series designed to be a cavalcade of disasters," Grassie said. "Rather, the series is designed to highlight a series of examples that point up our potential, and show how we draw on that potential to help us survive. ... It's something that has evolved over God knows how many centuries."

The under-the-skin views will be familiar to anyone who's gone to a "Body Worlds" exhibit - or, for that matter, has watched "CSI," "House" or other TV shows that zoom inside the body. Grassie said that "Human Body" aims to increase the scientific quotient - and decrease the icky-innards quotient.

"There are some people who just don't want to look," he said. "So what we wanted to do is to focus on process, function, and how to present it in a way that we felt would be intriguing and nonthreatening."

Shows of strength merely provide the opening theme for the four-hour series, which also touches upon brain power, sight and sensation. Two episodes premiere on Sunday, and the two others will roll out on March 9 - with frequent repeat broadcasts. Grassie said the shows may also be coming to a school near you, complete with lesson plans developed to complement the educational videos.

For Grassie, the bottom line is to give viewers an appreciation of the "true potential inside each of us." Although the feats depicted may seem superhuman, Grassie they are actually within the capability of most people when they're pushed to the limit (or when they're trained to the limit). Here are just some of the factoids presented during the series:

• Two hundred muscles come into play when you walk, and you use 100 muscles when steering a car. Even lifting a cup of coffee exercises 70 muscles. Normally, your muscles use only a third of their fibers at a time. But in extreme situations, like lifting a half-ton rock to save your life, all those fibers come into play. (Don't try that at home.)
• When a ballerina dances on the tips of her toes, the force on those toes is equivalent to having three elephants stacked on top of each other. The real trick behind en pointe training has to do with tolerating, and even blocking out, the pain of that exercise.
• The bands of ligaments that wrap around your knee can bear 7 tons of weight before giving way.

"If people come away saying, 'Gee, I didn't know that,' we've accomplished our task," Grassie said.

Chances are you'll be saying that at least once while you're watching "Human Body."

For more of those "I-didn't-know-that" moments, check out Discovery.com's "Human Body Explorer," as well as msnbc.com's interactive roadmap for the human brain, a look at the biology of a heart attack, and a graphical guide to the molecular motors inside your cells.

Update for 12:15 a.m. March 1: Todd Schroeder, a biokinesiologist at the University of Southern California who appears on "Human Body," got back to me during the afternoon and said he's looking forward to seeing the show on Sunday.

"I'm hoping they sell it as showing that the body is an incredible machine, and there are many components that fit together, and if stimulated at the right time with the right mechanism, you can generate incredible feats of survival," he told me.

However, he added, there's a reason why those feats are usually once-in-a-lifetime experiences.

"The body could not withstand that on a day-to-day or repetitive basis," he observed. "It's not something that should happen on a regular basis."

For example, he's worked with lots of athletes who are looking for an extra edge in the muscle department.

"You have individuals who are skinny, and they want to put on muscle mass ... and they put on one pound of muscle mass," Schroeder said. "That translates into five pounds of force on the knee. For five more pounds of muscle, that's 25 more pounds of force. Over time, that can be detrimental in terms of breakdowns of the joints."

Another issue relates to a routine known as whole-body vibration, Schroeder noted. The technique involves standing on a vibrating plate and literally jiggling your way to better fitness. Schroeder said whole-body vibration started out as a way to stimulate bone growth, and lately it's been touted as a method for burning off fat and enhancing muscle tone. However, all that jiggling may not be good for you in the long run - as jackhammer operators can attest.

"It's a matter of finding out what level of whole-body vibration is appropriate," Schroeder said.

Ironically, Schroeder himself is now in a position that requires bone-growth stimulation. He told me that he got pretty banged up in a snowboard accident a few weeks ago, and now he has to get around on crutches.

In the TV show, the first survival story is about the guy who was knocked unconscious during a tornado, swept up by the twister and dropped back down without breaking a bone. Schroeder surmised that the guy in the tornado survived relatively unscathed because he went totally limp - but when Schroeder had his own accident, he couldn't take advantage of that trick.

"I didn't have time to react in that way," Schroeder said."I wish I had."

DOD

CLICK FOR VIDEO   Watch Pentagon video   of the missile intercept.

This week we exploded five of the myths surrounding last week's spy satellite smash-up, in a report from NBC News space analyst James Oberg. The first myth-buster was that the missile intercept really wasn't a "shootdown," in the sense of a rifle shot that brought down a bird, but was a messier breakup of both the target satellite and the missile interceptor.

Oberg's No. 4 myth was that the Pentagon was actually aiming directly at the biggest potential hazard on the satellite, a tank filled with half a ton of frozen hydrazine fuel. He said it was "hard to imagine" how the warhead's guidance system could have spotted the target on its blobby view of the satellite.

Now Oberg says he'd like to expand upon that remark, based on feedback he's just received from the Pentagon's Missile Defense Agency. It turns out that the SM-3 missile changed its flight path to get as close as it could to the tank. The feedback came from a high-level official, who provided information on a not-for-attribution basis because the official was not authorized to respond publicly. Here's how Oberg summarized the response:

"Actually, while they did not 'aim at the tank' in their gunsight, the Navy space sharpshooters really did target for the tank's known location within the satellite's structure. According to a Missile Defense Agency response to questions from msnbc.com, 'The [warhead] seeker computes an aimpoint on the target's image that it sees as they come together (quickly), and moves to maximize hit effectiveness. The kinetic warhead (kill vehicle) then sharpened the aim at end game as noted above to move to a sweeter spot on the target.'

"This implies an amazing degree of real-time pattern recognition by the warhead's guidance system. This is a BIG WOW to me. ... I stand corrected, and impressed."

On another point, there had been reports that only 17 pieces of debris from the satellite were still being tracked - but today, veteran satellite tracker Ted Molczan reports on the SeeSat-L discussion board that 42 pieces are on the list. Oberg also notes that the Federal Aviation Administration's warning about falling satellite debris is effective through March 9.

Ironically, the smash-up of one spy satellite has forced a delay in the launch of another spy satellite. So there's no question that the orbital debris is having an effect on the space environment. To claim otherwise would give rise to Myth No. 6.

• The Economist: From geeks to greens
• Johns Hopkins Medicine: This is your brain on jazz
• National Geographic: The hunt for the God particle
• Popular Mechanics: The quest for fusion power at MIT

NIST

Atomic clocks can be as small as computer chips.

It took astronomers 5,000 years or so to figure out how leap years work - and with every technological leap, we're becoming increasingly dependent on ultra-precise timekeeping.

As a result, even tiny leaps in time are becoming just as important - and just as controversial - as leap days and leap weeks must have seemed back in the days of Julius Caesar and Pope Gregory XIII.

We have Julius and Gregory to thank for Friday's leap day, the extra day that's periodically tacked onto the month of February.

Even before Julius Caesar's reign, the ancients had figured out that a 365-day year came closest to matching the annual round of equinoxes and solstices, which were so important for planting schedules and holy rites linked to astronomical observations. But over the years, the seasons gradually fell out of sync, and extra days had to be stuck in haphazardly to put the year back on track.

With an assist from the astronomer Sosigenes, Julius Caesar instituted the much more reliable Julian calendar, which stuck a 366th day in the month of February every four years. (OK, when the Romans started the leap-year habit in 45 B.C., they added a leap day every three years. Which was bad. But eventually they got it right.)

There was still a slight discrepancy between the calendar cycle and Earth's actual solar year, however, and by the time Gregory entered the picture in the year 1582, the difference added up to 10 days. Armed with updated astronomical advice, the pope revised the calendar again, and added an exception to the four-year leap rule. Leap days would be added to century years divisible by 400 (such as 2000), but not to the other century years (such as 1900 or 2100).

And that's where we're at right now. Even Gregory didn't completely solve the problem. There are still little discrepancies that crop up between the calendar and our planet's yearly rounds. If you could check Earth's precise position in its orbit year over year, you'd find an average yearly discrepancy of 26 seconds.

John Lowe, leader of the atomic standards group at the National Institute of Standards and Technology's Time and Frequency Division, said that gap isn't close to requiring any correction ... yet.

"It's going to take 3,300 years for one day of slippage," Lowe told me today. "I doubt anybody is worrying about that right now."

So don't expect any additional tweaking to the Gregorian calendar until, say, the year 5000 or so. There is another leap-time issue that will have to be resolved much sooner than that, however. One of the biggest dilemmas facing timekeepers today has to do with the leap seconds that have been added to the year periodically since 1972.

Leap seconds aren't directly related to the length of the year, but rather to an infinitesimal difference between the length of a 24-hour day (that is, 86,400 seconds) and the international atomic standard for the length of a second. The difference (known in geekspeak as DUT1) accumulates because our planet's rotation is gradually slowing down.

Every time the gap between atomic and astronomical time reaches 0.9 seconds, a leap second is added to bring the two standards back into sync. Right now, the gap is almost 0.4 seconds - but Geoff Chester, an astronomer at the U.S. Naval Observatory, says the discrepancy could start picking up speed.

"Fifty years or so from now, it's entirely possible that we may be adding two or as many as four leap seconds per year," Chester told me.

That's very inconvenient for the folks who rely on the precise, steady timekeeping of the atomic system - such as the people in charge of the world's computer networks, power grids and even the Global Positioning System.

"Sooner rather than later, this is going to become a real nuisance, so there is debate right now over how we're going to reduce this nuisance factor," Chester said. "The simplest solution is just to do away with the leap second."

However, that doesn't sit too well with the folks who deal with timekeeping in the astronomical world. Without the leap seconds, the atomic time standard would run further and further ahead of natural time cycles.

"If we did away with leap seconds, we would find ourselves at some time in the same position that they did in the 1500s - one minute off, two minutes off, five minutes," NIST's Lowe said. "All of the charts and tables stating sunrise and sunset, those would all have to be adjusted periodically to accommodate the slipping time scale."

Earth's time lords, at the International Earth Rotation and Reference Systems Service as well as at the International Telecommunications Union, have been talking about proposals to do away with leap seconds, or at least wait until the discrepancy adds up to a leap hour. Lowe and Chester say their organizations have no position for or against the idea, but will do whatever the international standard-setters tell them to do.

Lowe doesn't expect a resolution of the dilemma anytime soon - and in the meantime, there's likely to be more leap seconds added to the clock. "This has been going on for the last dozen years," he said. "Large international bodies like these never proceed too quickly."

But one thing is for sure: Every year, society is becoming more and more dependent on precision timekeeping. For Lowe and his colleagues, the most important job isn't whether an extra day is added to a year, or whether an extra second is added to a minute. Rather, it's to make sure that every second of the year is accurate and accounted for.

"We build these highly precise clocks not to define the time of day, but to define the length of a second," Lowe said. "That defines frequency, so many cycles per second - and frequency is what drives our technological world, from television and radio to our global telecommunication systems. The big satellites that carry massive amounts of data operate at a very high frequency, so they need very stable calibration.

"That's why we build these incredibly accurate instruments," he said. And that's why every second counts.

Update for 9 p.m. ET Feb. 28: I revised my reference to the 26-second annual discrepancy between the Gregorian calendar year and the tropical year (which adds up to one day in 3,300 years or so), because the actual discrepancy can't be judged on a year-over-year basis. For more about the so-called 4,000-year rule, check out this Web page.

Also, to celebrate leap day, you can either propose to your beau (if you're a woman) or try out the Project Leap Year Web site, which gives you the opportunity to share your leap-day dreams. See if you can find my dream destination!

Update for 1 p.m. ET Feb. 29: I fixed the reference to the Gregorian vs. Julian difference to 10 instead of 11 days. The calendar did jump 11 days when the changeover was made, from Oct. 4 to Oct. 15, 1582, but of course one of those days was the usual turnover from Thursday to Friday.

Also, my msnbc.com colleague Lori Smith points out that this year brings an entire leap month on the Jewish calendar.

Update for 2:30 p.m. ET Feb. 29: Check out these leap-day video clips: On NBC's TODAY show, Marina Maiuri follows through on the age-old tradition by popping the question to her boyfriend. And on MSNBC's "ZeitGeist," Willie Geist takes advantage of the extra day to pander to you with new video of a cute baby polar bear and other diversions.

• Cosmic Variance: What's the (dark) matter?
• NASA: Vehicles take off-roading out of this world
• CMU: New language developed for educational robots
• IBM: How much does it take to move an atom? (via Slashdot)

Microsoft Research

The galaxy M81 makes its  appearance in a screenshot from  the WorldWide Telescope. Click on  the image for a larger version.

After weeks of rumblings in the blogosphere, Microsoft Research's WorldWide Telescope was brought out in the open for the first time today, at the annual TED conference in Monterey, Calif. The software program knits together terabytes of online data into a seamless, zoomable experience - and lets users create their own guided tours of the deep sky.

Even though the free program was demonstrated today, it's still said to be in private alpha mode, which means it could be several weeks before you can try it out for yourselves.

On one level, the WorldWide Telescope is sure to be compared with Google Sky - but the ability to build your own multimedia planetarium show just might kick things up a notch.

The program drew its first big raves a couple of weeks ago, when tech überblogger Robert Scoble said seeing the Telescope in action brought tears to his eyes. Today, Scoble provided the why behind the cry, including this reason: "I cried because I imagined all the kids, like my sons, who will be inspired by what they see. It took me back to the days when John Kennedy wanted us to go to the moon. Hint: there's a lot more out there to explore."

I've gotten a good idea of how much is out there when it comes to the WorldWide Telescope, in part because msnbc.com's Web operation is based on the Microsoft campus. (Microsoft is a partner in the msnbc.com joint venture). But it's mostly because I love to find out about cool astronomy software, and some people are willing to tell me about it. What follows is based on the impressions of people who have seen demonstrations of the program.

Like Google Sky, the WorldWide Telescope lays out the night sky in a browserlike interface, and you can mouse and zoom your way down to the good stuff: imagery from full-sky surveys conducted by ground-based telescopes, to be sure, but also close-ups from planetary probes and space telescopes.

There's a strong "social media" component to the presentation as well. For example, you can watch and listen as astronomers tell their stories about sky highlights, while the program automatically hops from one celestial object to the next. You can jump off the virtual tour at any point, take a look around for yourself, then jump back on the tour or latch onto a different cosmic excursion.

In its finished form, the program will provide the capability to set up and share your own sight-and-sound tours - which echoes the way Google Earth users have created their own mashups of maps and satellite imagery. The idea is to make creating virtual planetarium tours as easy as slapping together a PowerPoint slide presentation.

According to the project's FAQ file, the program is based on what Microsoft is calling its Visual Experience Engine, which sounds as if it works somewhat like the Microsoft HDView technology that msnbc.com is starting to use in zoomable slide shows. The software downloads higher-resolution versions of the imagery over the Internet as you zoom in. Thus, a lot of the heavy lifting is done over your network bandwidth - and I'm guessing that the more bandwidth and processing power you have, the better your visual experience will be.

Microsoft is already sending out quotes from some of the people who have been developing content for the Telescope's "visualization environment," including this one from Roy Gould of the Harvard-Smithsonian Center for Astrophysics:

"The WorldWide Telescope takes the best images from the greatest telescopes on Earth ... and in space ... and assembles them into a seamless, holistic view of the universe. This new resource will change the way we do astronomy ... the way we teach astronomy ... and, most importantly, I think it's going to change the way we see ourselves in the universe. The creators of the WorldWide Telescope have now given us a way to have a dialogue with our universe."

Scientists could theoretically use the program to compare different data sets and make discoveries - but the primary applications are likely to be for entertainment and education, at home, in the classroom and on big screens in museums and science centers.

"It really brings space to the public," Pete Worden, director of NASA's Ames Research Center, said in a video clip distributed by Microsoft.

Ames Research Center is in Mountain View, Calif., which is also where Google has its headquarters. Like Google Earth and Google Sky, Microsoft plans to distribute WorldWide Telescope at no charge. But the company could well use the underlying technology for other types of immersive experiences on a pay-for-play basis.

We won't know the full capability of the WorldWide Telescope until this spring, if Microsoft holds to the schedule it's announced. That leaves plenty of time for musing: Will this be a program truly worth weeping over? Or will it look like a case of "me-too" with some extra bells and whistles, coming in the wake of Google Sky? Feel free to weigh in below with your comments, as well as your recommendations of virtual sky software and Web sites.

Update for 9:20 p.m. ET: Giving credit where credit is due, Microsoft said the WorldWide Telescope builds on work that started with computer scientist Jim Gray's work on SkyServer and the Sloan Digital Sky Survey. The new program has been dedicated to Gray's memory. Here's a short article by Gray and Alexander Szalay that lays out the philosophy behind the project. Curtis Wong of Microsoft Research's Next Media group plays a lead role in the WorldWide Telescope project and conducted today's demonstration at TED.

In case the screenshot I've linked up above isn't enough for you, here's another one from Microsoft Research that highlights the Andromeda Galaxy, and yet another one that focuses on the Hubble Ultra Deep Field. But to be honest, none of the screenshots truly does justice to the Telescope's depths of data.

I can't let this subject go without mentioning Stellarium, an open-source astronomy program that many users say is better than Google Sky.

Update for 11 p.m. ET: Over at Sky & Telescope's Web site, Stuart Goldman says that he's had the alpha version of the software for some time. At the moment, the WorldWide Telescope "doesn't play well with the video on my work computer," he said. That's a potential downer, because the program is said to be quite graphics-intensive.

• Universe Today: An entire galaxy, seen in ultraviolet
• Technology Review: Between friends (via GeekPress)
• Improbable Research: Honey vs. vinegar for catching flies
• Onion Radio: Mechanical pencils turn on human overlords

Thousands of robots are already on the battlefield in Iraq and Afghanistan, but what happens when you hand the robot a gun and turn it loose?

Some researchers fear that giving military robots autonomy as well as ammo is the first step toward a "Terminator"-style nightmare, while others suggest that in some scenarios, weapon-wielding robots could someday act more humanely than humans.

The pros and cons of killer robots are taking center stage Wednesday in London, at what's considered the world's oldest military think tank, the Royal United Services Institute.

On one side of the issue is Ronald Arkin, a robotics researcher at Georgia Tech who is working on a Pentagon-funded project to build a sense of ethics into battlefield robots - "an artificial conscience, if you will," he told me.

AP

Design engineer Gary Morin demonstrates Foster-Miller's weaponized SWORDS robot.

"The basic rule is to try to engineer a system that will comply as best it can, given the information that it has, with the laws of war," Arkin explained. "And it's my belief that eventually we can do better than humans in this regard."

On the other side is Noel Sharkey, a robotics expert at Britain's University of Sheffield who served as chief judge for the long-running TV show "Robot Wars." 

Nowadays, Sharkey is sounding the alarm about the prospect of real-life robot wars: He's calling for an international ban on autonomous weapon systems until it can be shown that they can obey the laws of war.

"I think we should be addressing this immediately," Sharkey told me. "I think we've already stepped over the line."

Killer robots aren't on their own ... yet
That doesn't mean killer robots are on the loose. To date, the battlefield 'bots have been used as not-so-autonomous extensions of human warfighting capabilities. For example, the missile-armed Predator drones that have played such a prominent role in Iraq and Afghanistan are remote-controlled by teams of living, breathing pilots.

On the ground, robots have traditionally done reconnaissance or hunted for roadside bombs. Just recently, the Pentagon just went through a tangled procurement process to order up to 3,000 next-generation machines. (After a legal battle, the contract was won by iRobot, which also makes the Roomba vacuum cleaner and other robotic helpers.)

Last year, the Pentagon started sending gun-toting robots to Iraq, but even those robots aren't designed for autonomous operation. Instead, they're remote-controlled by human operators and are equipped with fail-safe systems that shut them down if they go haywire.

What worries Sharkey is that the military may be on a slippery slope leading to a robotic arms race. "My real concern is that the policies are going to make themselves, that the 'autonomization' of weapons will creep in piecemeal," he told me.

For example, Sharkey pointed out that the Pentagon is already on a path to make a third of its ground combat vehicles autonomous by 2015. "Then you'll put a weapon in one of them, and then it will gradually creep in bit by bit.," he said.

He also pointed to the Pentagon's roadmap for billions of dollars' worth of robotic research over the next 25 years. As the United States and its allies put more and more robots on the battlefield, their rivals will surely follow. "Once you build them, they're easy to copy," Sharkey said. "The trouble is that we can't really put the genie back in the bottle."

Even if the United States takes care to build robots with a "conscience," others may feel under no pressure to do likewise. A couple of years ago, Iranian-backed Hezbollah guerrillas sent a remote-controlled drone over Israel, and Sharkey said al-Qaida and other terrorists could follow suit with their own breeds of robo-bombers.

"If you don't really give a toss, you can just put an autonomous weapon running into a crowd anywhere," Sharkey said. "It's only a matter of time before that happens."

Killer robots with a conscience?
Arkin agrees with Sharkey that it's high time to start thinking about the implications of autonomous weapon systems.

"I think that's a reasonable debate, and there's good reason to have that debate at this time, just so we understand what we're creating," he said. "I would be content if it was decided that autonomous systems have to be banned from the battlefield completely."

But when it comes to designing the combat systems of the future, Arkin argued that there should be a place for autonomy, or at least an embedded sense of ethics. He pointed out that humans haven't always had a good track record on battlefield behavior.

"Human performance, unfortunately, is a relatively low bar," Arkin said.

One of Arkin's suggestions would apply even if a robot is under human control: The robot should be able to sense if something wasn't right about what it was being asked to do - and then require the human operator to override the robot's artificial conscience.

In other scenarios, the data flooding in about a potentially threatening encounter might be so overwhelming that mere mortals would not be able to process the input in time to make the right decision. "Ultimately, robots will have more sensors and better sensors than humans have to see the situation," Arkin said.

Arkin said he doesn't advocate the idea of creating robot armies to sweep over a battlefield. Rather, they would be used for targeted applications: For example, once an urban area is cleared of civilians, a robot could be set up to watch out for snipers and fire back autonomously, he said.

"The impact of the research I'm doing is, hopefully, going to save lives," he said.

But Arkin described his efforts as mere "baby steps" toward the creation of battlebots with a conscience. "There are no milestones or timetables for doing this right now," he said. "We're pioneering this work to see where it would lead."

New laws of robotics
This work goes way beyond science-fiction author Isaac Asimov's Three Laws of Robotics, which supposedly ruled out scenarios where robots could harm humans.

"Asimov contributed greatly in the sense that he put up a straw man to get the debate going on robotics," Arkin said. "But it's not a basis for morality. He created [the Three Laws] deliberately with gaps so you could have some interesting stories."

Even without the Three Laws, there's plenty in today's debate over battlefield robotics to keep novelists and philosophers busy: Is it immoral to wage robotic war on humans? How many civilian casualties are acceptable when a robot is doing the fighting? If a killer robot goes haywire, who (or what) goes before the war-crimes tribunal?

Sharkey said such questions should go before an international body that has the power to develop a treaty on autonomous weapons.

"In 1950, The New York Times was calling for a U.N. commission on robotic weapons," Sharkey said. "Here we are, 57 years later, and it's actually coming to pass - and we still haven't got it."

Update for 9:30 p.m. ET Feb. 26: I probably haven't done full justice to either Arkin's or Sharkey's point of view. For more about Arkin's work on robotic ethics, including a meaty technical report, check out his home page at Georgia Tech. For more about Sharkey's views, click on over to this article from Computer Magazine as well as his home page at the University of Sheffield.

Update for 6:30 p.m. ET Feb. 27: A sharp-eyed reader said that the picture of the robot I originally used on this item was not actually equipped with a gun. I've replaced that picture with a different one showing the right robot. Thanks for setting me straight, Remoteman!

• Discovery.com: How the pyramids were planned
• Telegraph: How high can fish count? (via Slashdot)
• Scientific American: How will the night sky evolve?
• Ars Technica: Why the public is confused about science

Michael Farmer

Meteorite hunter Michael Farmer kneels at the rim of a crater in Peru.

Five months after a meteorite made an international splash in Peru, experts are suggesting explanations for some of the space rock's effects - for example, the sickening odor villagers smelled at the crash site, and the bubbles that were seen emanating from the water-filled crater left behind. But a study due to be presented next month also raises fundamental questions about the event. In fact, an international research team declares that the impact "should not have happened" at all.

Yet another study sets forth a mystery surrounding two other meteorites found in Antarctica a couple of years ago. The rocks don't match any other class of meteorite - so where did they come from?

The two studies are among hundreds submitted for the annual Lunar and Planetary Science Conference, scheduled March 10-14 in League City, Texas. The conference offers the cream of the crop in planetary science - focusing on topics ranging from the solar wind, to Mercury and Mars, to the icy dwarfs on the solar system's edge.

The Peruvian meteorite impact comes in for a fresh round of scientific scrutiny in a study submitted by researchers from Brown University and institutes in Peru and Uruguay. Just after the impact was reported, some scientists doubted whether a meteorite was actually responsible for the crater - but subsequent analysis proved that a stony space rock was involved (as opposed to a denser iron meteorite).

Scientists previously thought that stony meteorites on the scale of the one that hit Peru would break apart into little pieces before they hit the ground. The fact that this one survived to create a 40-foot-wide crater threw the researchers what they called a "hypervelocity curveball." They said the standard model used to estimate the effects of stony meteorites will need to be revised as a result.

The study does propose two possible explanations for the reports of "boiling water" seen within the crater: The bubbles could have come from the compressed air that surrounded the meteorite as it blasted into the wet earth - or it could have been caused by clumps of clay that dissolved and frothed as they fell into the crater.

"These two processes may have been responsible for local reports of water bubbling up from the floor soon after impact," the researchers wrote. "While there would have been heat generated at impact, it is unlikely that this could have sustained bubbling an hour later."

Meteorite hunter Michael Farmer, who visited the site last year soon after the impact, has said the sickening odor that villagers said emanated from the crater was most likely caused by sulfurous compounds such as triolite interacting with the ground water - and there's nothing in the latest study that contradicts that suggestion.

The Peruvian meteorite may be in for another shot at fame: Just last week, Living in Peru reported that Japanese investors are interested in building a space museum near the impact site, and that National Geographic is planning a documentary about the meteorite.

Now to the other space-rock study: Meteorite hunters from the Lunar and Planetary Institute and NASA's Johnson Space Center reported finding a pair of specimens in 2006 in Antarctica's Graves Nunataks area.

"These meteorites are not obviously like any other meteorites, so their origin is unclear," the Lunar and Planetary Institute said in its media advisory. "The mineralogy and chemical composition of these meteorites are so unusual that scientists have been struggling to find the right term to describe them. Numerous parent bodies have been proposed. Could they have come from the moon? From Venus? Scientists are currently debating these issues."

The researchers behind the study say they're not finished with their analysis of the rocks, and more findings may emerge at next month's conference. So stay tuned as the meteorite tales and other mysteries are fully brought to light.

•  Science News: Jelly propulsion
• The New Yorker: Numbers guy
• The Space Review: Hale and farewell
• Telegraph: Fresh tests on Shroud of Turin
• Daily Mail: Real-life quest for the Lost Ark (via Daily Grail)

Pictures from Europe's Venus Express orbiter are providing new insights - and raising new questions - about Venusian weather systems that are fueled not by water, as on Earth, but by sulfuric acid.

For almost two years, the probe has been documenting what's going on within and beneath Venus' globe-girdling clouds. In visible light, the planet is a nearly featureless marble - but in ultraviolet light, the clouds and hazes swirl in fast-moving patterns. So fast-moving, in fact, that scientists wonder how Venus' atmosphere can do what it does.

ESA/ MPS / DLR / IDA

This ultraviolet view from Venus Express shows atmospheric patterns in Venus' southern hemisphere. Click on the image for a larger version.

A series of ultraviolet images captured last July and released on Thursday shows how a high-altitude veil of haze can brighten and dim in a matter of days, moving from the southern polar region to equatorial latitudes and back again.

The scientists behind the $226 million mission speculate that the process is driven by the production of sulfuric acid particles at upper altitudes.

"This bright haze layer is made of sulfuric acid," Dmitri Titov of Germany's Max Planck Institute for Solar System Research said in Thursday's image advisory from the European Space Agency. Titov is science coordinator for the Venus Express mission as well as co-investigator for the Venus Monitoring Camera, which took the images.

At lower altitudes, the planet's atmosphere is predominantly carbon dioxide, with small amounts of water vapor and sulfur dioxide gas. If some atmospheric process lifts those molecules above Venus' cloud tops, they are exposed to the sun's ultraviolet rays and become highly reactive. That's what is thought to create the sulfuric-acid haze.

"The process is a bit similar to what happens with urban smog over cities," Titov said.

Scientists don't yet know exactly what atmospheric process is at work, and the European Space Agency says there's yet another mystery to be solved: The composition of the dark clouds seen on the Venus Monitoring Camera's ultraviolet images is still unknown. To figure out the answer, scientists plan to enlist yet another instrument on Venus Express, known as the Visible and Infrared Thermal Imaging Spectrometer.

While the Venus Express team works on that puzzler, you can check out the latest findings streaming in from other interplanetary probes, such as the Cassini spacecraft's study of Saturn's "mingling moons," Mars Reconnaissance Orbiter's look at the Red Planet's highest mountain (plus a belated Valentine) and a glimpse of Mars' grandest canyon from Europe's Mars Express, which is Venus Express' older brother.

And if that's not enough to keep you busy over the weekend, take a spin through our latest space slide shows, "Space Shots" and "Earth as Art."

Now it can be told: At the time that Virgin Galactic was rolling out the design for the SpaceShipTwo rocket plane, the spaceship's designer, Burt Rutan, was so ill he couldn't walk up a flight of stairs. In the wake of successful open-heart surgery on Feb. 7, Rutan reveals what was ailing him and says he's feeling better every day.

Michael Soluri

Burt Rutan answers questions during last month's SpaceShipTwo design rollout in New York.

Rutan, who will turn 65 this June, is the designer of SpaceShipTwo and its history-making predecessor, the SpaceShipOne rocket plane, as well as the record-setting Voyager and Virgin Atlantic GlobalFlyer round-the-world airplanes.

So although he's turning over more and more of the design duties to the next generation at Scaled Composites, the Southern California company he founded, he's still unquestionably a guiding light on the aerospace frontier. It would be a bad thing for Virgin Galactic, and arguably for the commercial space industry as well, if he were completely out of the picture.

During last month's design rollout, Rutan said he had "not been well lately" but held back on the details. Today, in a brief e-mail to journalists, he provided a more detailed update:

"For those medically inclined, my problem, constrictive pericardium, is explained in the link below. It gave me extreme fatigue for about 5 months.

"I had successful open-heart surgery at UCLA on Feb 7th to fix the problem. Feeling better every day. The complete recovery takes about 3 months.

"Burt's heart problem, 2007-2008: constrictive pericardium."

In a follow-up e-mail, Rutan confirmed that he wanted to get out the definitive word about his medical condition "rather than deal with rumors and the stuff that floats around the Internet." He also added a dramatic detail:

"I did have a very strong case of the disease, which is hard to diagnose, and was essentially out of commission for six months.  My appearance in NYC for the Virgin 'reveal' was real dicey, since I had no capability to go up even a flight of stairs."

I also asked Rutan about the investigation into last year's fatal accident at Scaled Composites, as well as the status of the SpaceShipTwo development effort, but Rutan provided no new information on that front.

Nevertheless, updates are filtering out from other sources: During a visit this week to Singapore, Virgin Galactic's Alex Tai reiterated what's been previously said about the time frame for SpaceShipTwo: Unpowered flight tests are to begin later this year, leading up to the first commercial flights around 2010.

At first, SpaceShipTwo would fly once a week, carrying clients to the edge of space at a cost of $200,000 per seat. Operations would gradually ramp up to two flights a day. Tai told Reuters that he expected the company to start turning a profit "inside the first five years."

Meanwhile, LiveScience has a report from Leonard David about Spaceport America's progress in New Mexico. The 18,000-acre site, 45 miles north of Las Cruces, N.M., will eventually serve as Virgin Galactic's headquarters.

The New Mexico Spaceport Authority says it's aiming to get a license from the Federal Aviation Administration and start putting out construction bids this summer, with completion slated for 2010 - just about the time SpaceShipTwo could be ready for paying passengers.

At least that's the current plan. Virgin Galactic officials, from billionaire founder Richard Branson on down, have said they won't be open for business until Rutan is sure that SpaceShipTwo is safe. So Branson and his team are probably breathing a sigh of relief to hear that Rutan appears to be safe and sound as well.

• Real Science: Listen to the surrogate science debate
• 'Nova' on PBS: 'The Four-Winged Dinosaur'
• The Economist: And now here is the virus forecast
• Daily Grail: The myth of the million-dollar challenge
• YouTube: Windows does music (via GeekPress)

DOD

CLICK FOR VIDEO   Watch Pentagon video   of the missile intercept.

About three dozen skywatchers in western Canada went out to see Wednesday night's total lunar eclipse and got a surprise bonus: the fireworks show created by the Pentagon's shootdown of a falling spy satellite.

Other aftereffects, including what may have been the plume created by the satellite's burning fuel, were seen back in Hawaii - near where the missile was launched for the orbital interception.

The Royal Astronomical Society of Canada's Prince George Center, located about 470 miles (750 kilometers) north of Vancouver, had long planned a public viewing event for the eclipse, said Brian Battersby, the group's Webmaster. A dozen members of the club and about twice that many non-members showed up, even though the viewing conditions were less than ideal.

"The clouds were unfortunately covering the eclipse for most of it," he told me.

Then there was a break in the clouds to the west. "My girlfriend turned around to look at the Andromeda Galaxy, which is named after our daughter," Battersby joked. "As she was looking for that, she noticed something and said, 'What's that!?'"

She and the other skywatchers spotted what appeared to be a persistent meteor trail, zooming from the southwest in their direction.

"I started noticing more of them, quite a few trails that we saw," Battersby said. "Six or so bright ones, and there must have been a dozen dimmer ones. They came in waves. It was quite a long stream of debris, not just a couple of isolated meteors."

It didn't take long to figure out that the "meteors" were almost certainly bits of debris from the impact between the spy satellite and a missile launched from a U.S. Navy cruiser thousands of miles away, near Hawaii. Satellite trackers knew that the spacecraft's projected path would take it over Canada, and the debris fell along the same path.

Unfortunately, the cameras had already been put away when the fireworks began, due to the disappointment over the eclipse, Battersby said. And the Prince George observers appeared to be in just the right place at the right time. Skywatchers in British Columbia's Okanagan region as well as Edmonton in the neighboring province of Alberta reported seeing no debris, Battersby said. It's not yet clear whether there were sightings farther north, either in Alaska or Canada.

There were some sightings back in Hawaii, however - and we're not just talking about the high-resolution missile video made by military spotters. On the SpaceWeather.com Web site, Maui photographer Rob Ratkowski reported a different kind of close encounter:

"I had my doubts about getting any images. I went to our site on Haleakala w/ Dr. JD Armstrong and pointed my 770mm refractor towards the direction believed to be the correct area. I spotted a fast moving point of light and began shooting frames. I knew that I had something and it was at the time the Navy stated. Also the AMOS 3.67 meter scope was also pointed in the same direction as mine and it tracked to the north and down what I believe was the path of the destroyed satellite. We then set up to shoot the eclipse as seen from Maui. Towards the end of the eclipse we noticed a long faint trail over the area of the satellite intercept that we believe to be the hydrazine vapor, it persisted into darkness. A very interesting evening on Maui."

Adrian Wyld / CP / AP

A sequence of images taken every 20 minutes shows the progress of Wednesday's total lunar eclipse.

Was it merely a lucky accident that the satellite intercept happened to occur during the total phase of Wednesday's lunar eclipse?

I'm sure the skywatching conditions weren't the top thing on President Bush's mind when he gave the go-ahead for the satellite intercept. There's no doubt, however, that the eclipse brought out more observers than might otherwise be watching for debris. And as any meteor-watcher knows, it's much easier to see what's going on in a dark sky when the moon's glare is gone.

Did you see the eclipse? Were you a Far North observer who spotted "meteors" during the same time frame, around 10:30 to 10:50 p.m. ET Wednesday? Feel free to add your reports as comments below.

If you completely missed the big show, you can get a vicarious thrill by checking out SpaceWeather.com's eclipse gallery and interactive photo map. You'll find a goodly number of videos of the eclipse over on YouTube. I particularly like this time-lapse video that shows you the progression from full moon to fully eclipsed moon. And if you want to learn more about the science behind lunar eclipses, check out our "Inconstant Moon" interactive.

Although we won't see another total lunar eclipse until 2010, there's a total solar eclipse coming up Aug. 1, and you can bet we'll have lots of coverage of that event. In the meantime, be prepared by clicking through our "Moonshadow" interactive.

Update for 2:20 p.m. ET: Space.com has its own take on the shootdown sightings, with quotes from Ratkowski as well as a link to the See-Sat-L online forum, the place to be if you're a satellite fan. Smaller pieces of satellite debris may be coming down over the next day or two. It might be hard to distinguish them from run-of-the-mill meteors, but if anyone can figure it out, See-Sat-L's legions will.

This page on the Zarya Web site contains some great information about the spy satellite's ground track - illustrating why Prince George was in such a prime position for seeing the debris and showing the track(s) along which people could expect to see debris. People in Michigan, for example, were most likely to see debris during the third orbit after interception, which was significantly later than 10:30 p.m.

Update for 4:40 p.m. ET: We've just put up a First Person gallery of lunar eclipse photos that highlights images from msnbc.com users - and that means you! Take a look, vote for your favorite picture, and feel free to submit your own.

• Damn Interesting: Life without the moon (via Daily Grail)
• Improbable Research: Putting pressure on a penguin
• Cracked: The 15 most bizarre animal mating rituals
• ONN: Expert wasted entire life studying anteaters

STScI / NASA

Pluto and its satellite Charon are the larger objects in this Hubble Space Telescope image. Two even smaller satellites, Nix and Hydra, can be seen to the right.

How do you define a planet? Officials at the International Astronomical Union thought the matter was settled more than a year ago when it drew up a definition of planethood that separated little Pluto from its eight bigger siblings and put it in the dwarf-planet category. Boy, were they wrong.

Many astronomers say the definition that the IAU came up doesn't adequately reflect the diversity of worlds we see even in our own solar system - and arguably, might even exclude Jupiter as an official planet. Now a replay of the "Great Planet Debate" has been scheduled for August. Pluto may remain in the pint-size pigeonhole - but the other planets, in our solar system and beyond, would get their own pigeonholes as well.

The "Great Planet Debate" is due to begin on Aug. 14 at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md. Here's how the conference is described on APL's Web site:

"During the first two days of the conference, we will present what we have learned about planetary bodies over more than 40 years of robotic exploration of the Solar System and what we are learning about planets around other stars. The IAU's dynamical definition of a planet will be presented, as well as an alternative geophysical definition. The utility of each will be debated, along with other potential planet definitions.

"A public lecture and panel discussion, featuring scientists who are prominent in the debate on planet definitions, is planned for the evening of the second day, following a reception that concludes the scientific portion of the conference.

"The third day of the meeting will be an Educator Workshop to discuss how the question of 'The Great Planet Debate' should be treated in schools and how that can be used as a springboard to discuss science as a process, as well as other topics in planetary science."

So what's being proposed as an alternative to the IAU's definition? The answer comes in a paper prepared last year by one of the conference's organizers, Mark Sykes of the Planetary Science Institute:

"'A planet is an object orbiting a star that has mass sufficient to maintain a gravity-determined (hydrostatic equilibrium) shape.' More simply put, planets are 'round' objects that orbit stars. Spacecraft imagery reveals that it is at this point of 'roundness' that solar system bodies begin to exhibit geology - reflecting interior processes, not just impact history. Smaller bodies (e.g., asteroids) are irregular 'inactive' objects. This definition is easily extensible to objects around other stars, unlike the [IAU's] Prague definition. ..."

The idea of revisiting the definition of planethood was a lively topic in Boston earlier this week during the American Association for the Advancement of Science's annual meeting - and it was in that context that Alan Stern, NASA's associate administrator for science, mentioned the August event.

Before he was brought into the space agency, Stern was one of the most vocal critics of the IAU's definition in his role as principal investigator for NASA's New Horizons mission to Pluto - and he's long been calling for just the kind of debate that is now scheduled to take place in August.

David Morrison, senior scientist at the NASA Astrobiology Institute at Ames Research Center in California, said astronomers are gaining a growing appreciation of the "wonderful diversity that we're finding outside our own solar system as well as inside."

The growing consensus is that it's wrong to divide the planetary lineup into first-class and second-class worlds. Planetary scientists say it's better to think of rocky, terrestrial planets (such as Earth, Mars, Venus and Mercury); gas giants (Jupiter, Saturn, Uranus and Neptune) and dwarfs (Pluto, Eris and Ceres, for example).

Morrison said there would almost certainly be other categories to come.

"I think any definition that was based just on the objects in our own solar system is going to be blown away when we actually look at the variety of other solar systems and the variety of things we think of as planets," he told me.

IAU delegates are due to gather again next year in Rio de Janeiro, and there's been some talk that revisions in the definition of planethood may be offered at that meeting. But Morrison and many of his colleagues say they won't look to the IAU for guidance, even if the organization decides to reconsider its Prague resolution. 

"I don't think the IAU should have been in this business in the first place," Morrison said. "If you look in a dictionary and you look up any word, you'll usually find four or five or six definitions. There's not one unique definition. You don't need a big international body to pass resolutions and vote to define a word.

"I think the IAU should just drop it," he said.

What do you think? Feel free to weigh in with your own arguments for the next "Great Planet Debate."

Update for 1:15 a.m. ET Feb. 21: The Planetary Science Institute's Sykes got back to me with an e-mail that goes into more detail on his proposed definition:

"...The definition is simple - planets are round things (in hydrostatic equilibrium against gravity) that orbit stars. This was basically the same thing proposed to the IAU, against which the dynamicists revolted.

"Dynamicists tend to think of objects as point sources whose importance depends upon their gravitational effects on other objects. The problem at the IAU was that everyone was involved in whether or not Pluto would be a planet, so the discussion that I saw was less than scientific. The Pluto-huggers were pushing roundness, the Pluto-haters were pushing dynamical dominance.

"When I started thinking about it more closely, my thought was focused on the intrinsic physical processes we study on the very different worlds to which we have sent spacecraft over the past 40-plus years. These processes are all related to phenomena we study on Earth (atmospheric processes, tectonics, volcanism, life, etc.). What I noticed is that all the objects for which any of these processes are observed are round. All objects on which none of these processes are observed are irregular.

"There are some very interesting reasons why 'round' is important in this situation - dealing with the onset of differentiation, mantle convection, etc. ('geophysical processes'). For those of us who study the physical characteristics of planetary bodies, who want to identify those objects that are expected to share these processes as a means of focusing our own scientific investigations (and targeting spacecraft), the geophysical definition is useful and the IAU definition is not. The IAU definition is useful as well, but to a much narrower group of investigators who happen to dominate the IAU and are far from representative of the planetary community (more members of which belong to geophysical professional societies than astronomical societies, interestingly).

"So do we teach children about who is 'right' or who is 'wrong'? I don't think so. Because of the public interest in the topic, I think it is a wonderful opportunity to discuss science as a process instead of a list of dry 'facts' delivered from on high."

• The Space Review: Spysat down! 
• N.Y. Times: Turning greenhouse gas into gasoline?
• National Geographic: Egyptian 'warrior' tomb found
• Tech Review: The 10 emerging technologies of 2008

Science / Comstock / Corbis

For weeks, science-minded activists have been urging the presidential campaigns to stage a debate focusing on science and technology issues - and they finally got their wish over the weekend. Sort of.

Not a single presidential candidate was in sight at Saturday's event, organized as part of the American Association for the Advancement of Science's annual meeting. Instead, the advisers on technology policy for Democratic hopefuls Hillary Clinton and Barack Obama took turns answering questions about what their bosses would do if they were president. The face-off was far too sedate to be called a debate, but in some ways it was an eerie reflection of the bigger, bare-knuckled battle for the Democratic nomination.

On one side of the speaker's table was Thomas Kalil, the Clinton campaign's adviser on science, technology and innovation. Kalil spent eight years in the White House during the Bill Clinton administration, eventually rising to become the deputy assistant to the president for technology and economic policy, as well as deputy director of the National Economic Council. He's now assistant to the chancellor for technology policy at the University of California at Berkeley.

On the other side was Alec Ross, the Obama campaign's adviser on technology, media and telecommunications. Ross is also executive vice president for external affairs and co-founder of One Economy Corp., a nonprofit group that has helped extend broadband networks to low-income neighborhoods.

In the middle was moderator Claudia Dreifus, a New York Times science reporter. As for the missing Republicans: John McCain's campaign couldn't arrange to attend in time for the last-minute addition to the meeting's agenda, said Albert Teich, AAAS' director of science and policy programs.

"We did not hear from Governor [Mike] Huckabee or Ron Paul," Teich told the hundreds of attendees who filled the seats at one of the Hynes Convention Center's biggest meeting rooms.

Kalil started out with a PowerPoint presentation outlining Clinton's platform on science and technology: Spending on federal research would be doubled over the course of 10 years. Tax credits for research and experimentation would become permanent. Tuition tax credits and research fellowships would be expanded.

He said Clinton endorsed the creation of a research agency for energy technology, an upgrade for the post of science adviser, and the restoration of the Office of Technology Assessment. Kalil said Clinton would "restore integrity to science policy" - referring back to past cases in which the Bush administration was accused of bending scientific findings to fit political positions.

"This is wrong and has to stop," Kalil said.

Ross had no computer presentation. Instead, he referred his listeners to the Obama campaign's Web site, saying that "what we have is an extraordinary amount of specific detail." Among the high points: Federal money for basic research would be doubled in five years' time. A nationwide interoperable wireless network would be created for emergency services, finally following through on a 9/11 commission recommendation.

Obama would call for $10 billion per year to be spent on a five-year transition to electronic medical recordkeeping, and $150 billion to be spent over 10 years to promote biofuels, plug-in hybrid cars and other emerging energy technologies. A clean-technology venture capital fund would be set up with $10 billion to invest annually for five years. The money collected for the telecom industry's Universal Service Fund would go exclusively to extending advanced broadband networks rather than funding "yesterday's technology."

"I think that we've gone very far in helping to set a North Star for where we want America to go over the next four and eight years in the science and technology space," Ross said.

What are the differences?
It's interesting to note that both candidates are on board  for a doubling in federal research funds ... just as President Bush is. (The trick is getting Congress to go along without loading up the legislation with earmarks.)

As Dreifus sifted through the written questions handed in by the audience, she asked each aide to spell out what distinguished his candidate from the other guy's when it came to science and technology issues.

Kalil said Clinton was "the only candidate who has devoted an entire speech to this issue, and she's also been more specific on the types of research investment that she believes are necessary to restore America's economic competitiveness." (Here's a recap of that speech.)

"I would simply respond to that by [saying,] go to the Web sites and actually check who is far more detailed - both in terms of breadth as well as in terms of detail," Ross answered.

Each aide also said his respective candidate would outshine McCain on science and technology issues. (What else would you expect them to say?) Ross noted disapprovingly that McCain once said "he would assign things that are 'less important,' like technology, to his vice president." (Here's more on that quote.)

For his part, Kalil acknowledged that McCain "has distinguished himself from some of the other Republicans," specifically on addressing climate change. "However, if you look at the positions that he's taken so far on science and technology, they're almost non-existent," Kalil said.

The two aides came the closest to drawing an actual contrast when it came to space policy - specifically, NASA's $104 billion plan to retire the shuttle fleet and return to the moon in a new type of spaceship. Kalil said Clinton believes that "it's necessary to maintain an emphasis on human exploration as part of the NASA program, but she also believes that we need to have support for the Earth sciences program," particularly for studying climate change.

In the past, the Obama campaign has hinted that the moon effort might be put on hold to help fund education programs, and last month the SpaceRef Web site passed along a more detailed statement on space policy, attributed to the campaign. But Ross played it coy on Saturday.

"I'm not allowed to scoop anything, but anticipate some specific policies on NASA and specific to space exploration in the next month," Ross said. He did hint that climate research might play a bigger role in the Obama administration's NASA - and that the Bush administration's vision might be in for revision.

Ross said that when President Bush announced the moon program, just over four years ago, Obama "responded at the time with skepticism, and I think that skepticism has been validated in the time since." Ross' reference wasn't immediately clear, but this cached article from the Chicago Sun-Times includes the requisite note of skepticism from Obama, who was running for the Senate at the time.

And the winner is ...
If Saturday's session is any guide, science and technology issues won't be significant factors in the Clinton vs. Obama duel. But the surrogate debate did bring politics into the spotlight during the nation's premier meeting on science and technology - and some in the audience took it pretty seriously.

One woman, for example, told me she thought Ross seemed so young and inexperienced that she stopped payment on the check she had just sent to the Obama campaign. She says she's now undecided. (She asked that her name not be used because she didn't want her employer and clients to know her political views.)

On the flip side, a couple of people told me that Kalil seemed so much a part of the tired old political establishment - and Ross seemed so passionate and well-spoken - that they were more inclined to support Obama.

Oddly enough, that divide between experience and passion, between the head and the heart, seems to reflect the key distinction between Clinton and Obama. And we're not even talking about the candidates themselves, but just a couple of their advisers!

Perhaps there'd be some real fireworks if the candidates showed up in person to go after each other on science and technology issues. The coalition known as Science Debate 2008 is hoping for just that, and has invited Clinton and Obama as well as McCain and Huckabee to an April 18 event in Philadelphia.

Would Clinton show up? "Time will tell," Kalil said. And Obama? "It's being given very serious consideration," Ross said.

"I was very encouraged to hear that," said Lawrence Krauss, a theoretical physicist at Case Western Reserve University and one of the prime movers behind Science Debate 2008. He told me that he rates the chances of the April debate actually happening at 20 percent, which is far more optimistic than he was feeling a week ago.

However, if you had to have just one debate on science and technology, it'd be better to have it between the Democratic and Republican nominees, after the conventions. At least that's the view of former Defense Secretary William Perry, who chaired the committee behind a new list of Grand Challenges for Engineering.

Such a debate would have a better chance of highlighting genuine differences on embryonic stem cell research, on nuclear power and other energy issues, on the balance between scientific openness and national security ... and the list goes on. No matter who scores the most debating points, voters who are anxious to hear the candidates' visions for America's future would come out the winners.

What do you think? Feel free to weigh in with your political strategies in the comment section below. If you're looking for more information about Saturday's surrogate debate, check out the reports from the journal Science as well as from AFP, The Guardian, Congressional Quarterly, Discover Magazine and Space Politics. And for updates on the wider campaign, click on over to our political coverage.

• The New Yorker: Big foot
• Science News: Math on display
• Boston Globe: A most puzzling occupation
• The Gonzo Scientist: Can scientists dance?

Salvatore Di Nolfi / Keystone / AP

An onlooker watches an element of the Compact Muon Solenoid being lowered into its underground cavern at the Large Hadron Collider on the French-Swiss border.

The most anticipated date in physics is the day the world's biggest particle-smasher, Europe's Large Hadron Collider, goes into operation. That day had been set for last November, but a magnet mishap and other factors forced a delay until this spring. The final piece of one of the collider's mammoth detectors, the Compact Muon Solenoid, was lowered into its underground cavern just last month. And now the big day is likely to come in June or July rather than May.

The fact is that officials at Europe's CERN particle physics lab don't know to the day when the world's biggest physics project will be ready for prime time. However, they do know the day for the big celebration.

CERN's director general, Robert Aymar, is in Boston this week for the annual meeting of the American Association for the Advancement of Science - and construction progress on the Large Hadron Collider has been one of the big topics on the meeting's agenda.

The multibillion-dollar collider, which was conceived a quarter-century ago and has been in the works for more than a decade, is expected to shed light on mysteries ranging from dark matter and extra cosmic dimensions to the reasons why particles have mass and why matter won out over antimatter.

There's currently no other way to find out the answers to all these deep questions, Aymar said. "Without LHC discovery, we are stuck, and we will not go beyond what we know today," he told reporters. That's why the start-up is so anticipated.

Aymar said commissioning the machine will take months. 

Physics insiders have long known that the first beam of protons wouldn't be zipping through the collider's 17-mile-round ring until June or July - based on the construction time lines from CERN.

June was the time frame Aymar had in mind when he was asked about the start-up schedule during a Friday session on large-scale science project. But during a follow-up chat, he pointed out that you can't just press a big red button one day and expect each of the collider's beams to hit full power of 7 trillion electron volts immediately.

The rule of thumb is that 1 trillion electron volts, or 1 TeV, is equivalent to the energy expended by a mosquito in flight - which would make 7 TeV as energetic as, say, a bumblebee. The buzz of a bee may not sound like a lot. But when you consider how many trillions of protons are in that beam, the energy adds up to a bullet train going 100 mph. So it's prudent to start small and build up power gradually.

Aymar said that buildup could still start around May 21 or 22, with tests continuing for weeks after that. His aim is to have the collider conducting scientific experiments this summer.

Of course, that assumes that everything proceeds according to plan between now and then - which is not always the case (see above, "magnet mishap"). And now that sectors of the ring are being cooled down to cryogenic temperatures, any problem that needed fixing would required going through a whole warm-up/cool-down cycle.

"Quantification of the delay is three months," Aymar said - which is a geeky way of saying that a glitch in the final phase of preparations wouldn't hold up things by just a day, but rather three months at a time.

This may be why the big party - the ceremony marking the inauguration of the Large Hadron Collider - has been set for months after the scheduled start-up, on Oct. 21. French President Nicolas Sarkozy and other VIPs (including Energy Secretary Samuel Bodman) are expected to be in attendance.

No matter what happens, that date won't change, Aymar said.

And then what? Physicists have told me the first scientific experiments would probably need a year or so to come to fruition, and it could take five years to answer some of the deep mysteries mentioned above. If the answers are there to be found, that is. There's always a chance that the collider will draw a blank - that physicists won't see anything of what they're expecting to see.

"For many people, that may seem like a disappointment," said Lawrence Krauss, a theoretical physicist at Case Western Reserve University. "From a theoretical perspective, it means that every basic idea we have about the fundamental structure of matter, in some way, is wrong. And there's nothing more exciting than that."

Update for 1 p.m. ET Feb. 16: So how much does all this cost? As with all big-science projects, it depends. CERN says the cost of the accelerator is 4.7 billion Swiss francs ($4.3 billion), and additional CERN contributions to the experiments and project-related computing amount to 1.35 billion Swiss francs ($1.23 billion). But scores of other countries are contributing to the experiments as well, and that could add $3 billion to $5 billion to the total expense. Thus, if you're talking about CERN alone, the machine would cost $5 billion-plus, but if you're talking about the total project, the estimates are in the range of $8 billion to $10 billion.

Update for 8 p.m. ET Aug. 4: The original item was a little confusing about exactly what would happen on "Red Button Day." I've amended the text to say more clearly we're talking about the first injection of proton beams. Actual collisions would come later, and collisions at full power would come still later. Obviously, the schedule has slipped since this item was written. Here's today's update.

NASA / JPL-Caltech / Cornell

NASA's Spirit rover captured this view looking northward from the north edge of the Home Plate plateau, where it will be spending the Martian winter as a stationary "weather station." Click on the image for a larger version.

Life on ancient Mars just got tougher.

Not only was Martian water highly acidic in ancient times, but it was also extremely salty, researchers reported today in Boston at the annual meeting of the American Association for the Advancement of Science.

"In fact, it was salty enough that only a handful of known terrestrial organisms would have a ghost of a chance of surviving there when conditions were at their best," Harvard biologist Andrew Knoll, a member of the Mars rover science team, told reporters.

When you add in the earlier findings about how acidic Martian water was, back in the era when the rocks now being studied were formed, the picture of the Martian environment becomes so forbidding that Knoll couldn't think of any organism on Earth that could survive.

NASA / JPL-Caltech / Cornell

This view from NASA's Opportunity rover shows bedrock in a layer informally named "Gilbert," around the inside of Victoria Crater. A thin "fin" of rock rises from one of Gilbert's edges. Click on the image for a larger version.

"There aren't that many of those environments around," he observed. The organisms would have had to withstand the corrosiveness of water draining out from an acid mine as well as the salinity of water pooled on a salt flat.

Knoll's findings are based on an analysis of the minerals sampled by Opportunity as it explored the Martian plain known as Meridiani Planum, where it landed just over four years ago. The analysis looked at the present-day chemical content and worked backward in time, using a computer model as a "gauge of paleosalinity," Knoll said.

Other evidence comes from an analysis of one of the more recent pictures to come from Opportunity, a close-up of a rock known as Gilbert. The slab is covered with the blueberry-like stones that have been often been seen in Meridiani Planum. But it also sports what Knoll called "Cadillac-like fins" along an edge. He said those fins tell geologists that the rocks were formed by fluid flow but have been exposed to the elements for a long time.

For Knoll, the bottom line is that even the rocks of Meridiani Planum, where Opportunity found its best evidence for ancient water, would have been no place for life as we know it.

"By the time the Meridiani rocks formed, broadly speaking three and a half to four billion years ago, the planetary surface at Mars was ... my favorite three-word characterization is, 'arid, acidic and oxidizing,'" Knoll said. "That's not a very pleasant place to live, and it's a worse place to try to do the chemistry that is generally thought to have given rise to life on this planet."

NASA / JPL-Caltech / Cornell

This view from NASA's Opportunity rover shows a stretch of layered bedrock informally named "Lyell," part of a bright band around the inside of Victoria Crater. Click on the image for a larger version.

That means future probes would probably have to look elsewhere for evidence of life - either deep underground, or someplace where rock layers from the earliest epochs of Martian history were exposed, Knoll said.

"Probably the best place to look for evidence of Martian life ... is in Mars' earliest history, the first 500 or 600 million years, the interval that precedes the deposition of Meridiani Planum," Knoll said. "We know those places exist. They've been characterized from orbit."

The bad news is that Mars, like Earth, may have been hit by waves of extinction-level cosmic impacts during that time period - an epoch that geologists call the Late Heavy Bombardment.

But there's also good news, for Knoll as well as anyone else who wants more definitive answers to the questions about life on Mars:

• For one thing, Opportunity and its twin rover, Spirit, are still going strong after four years of operations on Mars. In fact, Cornell University astronomer Steve Squyres, the principal investigator for the Mars rover mission, noted that Spirit made its "biggest discovery" only recently. That discovery came when the rover kicked up a deposit of almost pure silica - which indicates that hot springs or steam vents were active during ancient times.
• For another thing, the Phoenix Mars Lander is due to land in Mars' north polar region in May. That probe is designed to dig into the cold ground and look for evidence of water and the other chemical building blocks for life.
• Finally, the Mars Science Laboratory, a rover far more capable than Spirit and Opportunity, is being readied for its 2009 mission to look for even more signs of ancient life. Richard Cook, project manager for the mission, said the list of potential landing sites has been whittled down to six promising candidates. "The real question is ... to try to find the place that not only could have been a habitable place in the past, but probably more importantly, [the place that] was able to preserve the signs that it could have been inhabited," Cook said.

No matter how the current life-on-Mars debate ends up, the prospects are good for having a permanent presence at the Red Planet from here on out, in the form of rovers and orbiters, said Charles Elachi, director of NASA's Jet Propulsion Laboratory.

"Think of them as robotic scientific stations which have been studying that planet for a decade, similar to the scientific stations we have in Antarctica. ... You're using them on a regular basis to understand what's happening, in this case, on another planet," Elachi said.

To review the past four years of Red Planet odysseys, check out our "Return to the Red Planet" archive and our slide show of "Mars' Greatest Hits," as well as NASA's Mars exploration Web site.

• 'Nova on PBS: 'Ape Genius' 
• BBC: Is HIV beating the scientists?
• Popular Science: Little love for space tourism
• New Frontiers: Carnival of Space 41

Don't expect to be eating cloneburgers anytime soon. At $13,500 per head, cloned cattle are just too expensive for the dinner table. But the great-grandchildren of clones? Those may well be on their way to the menu, and we might not even know it.

The intricacies of clone-tracking served as the first course on the menu of news conferences at the American Association for the Advancement of Science's annual meeting - a scientific feast that began today in Boston and continues through the President's Day weekend.

Clones can and should be tracked as they make their way through feedlots and food processing systems, said Patrick Cunningham, a geneticist who wears three hats. He's a researcher at Trinity College in Dublin; chief scientific adviser to the Irish government; and the co-founder and chairman of IdentiGen, a company that has developed DNA tracking methods.

IdentiGen's technology already is being used to trace meat back to its source based on DNA sampling - for example, to find out where an E. coli outbreak came from or to assure consumers that their hamburger didn't come from a genetically modified cow. Cunningham said somewhere around 70 to 75 percent of all beef in Europe was being tracked, with a "DNA eye in the sky supervising the whole thing."

The barcode for beef takes the form of 30 to 40 biomarkers, or SNPs (single nucleotide polymorphisms). All those barcodes are retained in a database that can be matched up with animal products, "right down to the hamburger," Cunningham said.

The same approach could be used to identify products from cloned cattle. "You track a clone the same way you track an individual in any population," Cunningham said.

The companies that sell cloned cattle are already working on a somewhat lower-tech registry for keeping track of their animals as they move through the supply chain, said the president of one of those companies, ViaGen's Mark Walton.

Last month, the Food and Drug Administration determined that food products from cloned cattle, pigs and goats were "as safe as food we eat every day." However, companies are still holding off from selling food from clones, primarily for marketing reasons. And Walton doubts that the clones themselves will be gobbled up for mass consumption anytime soon -basically because it costs almost 10 times as much to create a clone as it does to make a calf the old-fashioned way.

"If you think steak is expensive today, think about having a feedlot full of $13,500 animals," Walton joked.

Cunningham agreed. "I don't believe cloned food is realistic here in America or in Europe in our lifetime," he said.

Today, cloned animals are valued primarily as sires. Theoretically, a prize bull could be copied, so that a bevy of bulls could pass along the genetic advantages through more traditional breeding techniques. Walton said that's already happening. "I'm aware of one bull [from which] over 60,000 straws of semen have already been sold," he told me.

If people wanted to avoid consuming milk or meat from a cloned bull's offspring, could they do it? How far down the breeding line could a "no-clone zone" extend? Could IdentiGen's system detect a clone's progeny?

"Offspring of clones - yes, we can do," Cunningham told me. "It's a bit more challenging, because you only have half of the clone's genotype in the offspring, and it's mixed up with, usually, the maternal contribution. But that's feasible. I think once you move to the grandchildren and the great-grandchildren - first of all, I don't see where it would be justified, but I don't think it's feasible, either."

Doug Gurian-Sherman begs to differ. He's a senior scientist at the Union of Concerned Scientists, which is opposed to cloned food.

"It certainly can be done, with ear tags that have barcodes," he told me by telephone after today's news conference. "It's feasible to do, though it could be technically challenging."

His chief concern isn't so much the possibility that there's some nasty twist of DNA in a cloneburger - or hamburger made from the great-grandchild of a clone. Rather, he's worried that over time, the rise of the clones will reduce genetic diversity and gradually make the entire species more vulnerable to the sorts of problems that come with agricultural monocultures.

Even efforts to create disease-resistant cattle through cloning could backfire, Gurian-Sherman argued. "The more genetic uniformity you have, [the more] you're going to leave yourself open to dozens of other diseases," he said.

"The bottom line is that the most important public health issue is going to be that uniformity issue," Gurian-Sherman said.

How far do you think a no-clone zone should extend? Do you think a "clone-free" label should apply not only to the cow in question, but to the cow's family tree as well? Is that necessary, or even realistic? Check out the case for clones at CloneSafety.org, the case against clones at the Center for Food Safety - and then weigh in with your own opinion below.

Twentieth Century Fox / WETA Hayden Christensen portrays a man who finds he can teleport to the Great Pyramids and other exotic locales in the science-fiction movie "Jumper."

Everyone knows Anakin Skywalker can't really teleport himself to the Great Pyramids of Egypt, even though Anakin ... er, Hayden Christensen ... does just that in the movie "Jumper," opening Thursday. But isn't it possible to go through a wormhole in the space-time continuum? Wellllll, maybe - if you've got a galactic black hole's worth of power. Such are the issues that come up when science meets fiction, at the movie theater as well as in the classroom.

When scientists met up with Christensen and the director of "Jumper" at the Massachusetts Institute of Technology last month, neither side knew what to expect. But the result wasn't at all like the battle between the Jumpers and the Paladins in the movie. Both sides came away with that most sought-after Hollywood ingredient: a happy ending.

"The event was much more fun than I thought it would be," said MIT cosmologist Max Tegmark, who sat in a lecture hall along with quantum physicist Edward Farhi and a gaggle of students to watch a selection of scenes from the movie.

"It was actually an amazing experience. I was waiting to get shredded," said the movie's director, Doug Liman, a veteran of such big-name blockbusters as "The Bourne Identity" and "Mr. and Mrs. Smith."

In a telephone interview from Paris, where Liman was in the middle of a global publicity tour, the director recalled how he was thrown out of a physicist's office when he went looking for advice about teleportation. He was afraid the eggheads at MIT would react the same way, despite reassurances from the publicists.

"That just seemed like a recipe for disaster in terms of how I was going to come across," Liman told me. "But it was incredibly inspiring, because the physicists explained how they use movies to make physics more appealing and more magical."

Tegmark recalled that the affair had a party atmosphere, with some students sporting Darth Vader masks and lightsabers. "I remember thinking, 'Whoa, I never realized that MIT undergrads were such a bunch of groupies,'" he said with a laugh.

Getting technical about teleportation
The premise of "Jumper" is that the character played by Christensen somehow gains the power to teleport himself to distant locations, to get himself out of a jam or to save the girl.

Some of the advance publicity has compared the trick to quantum teleportation - but that would be wrong. As numerous bloggers have pointed out over the past couple of weeks, quantum teleportation is all about transferring information rather than beaming up in the "Star Trek" sense. In the movie (as well as the novel on which the movie is based), the main character doesn't know how he does what he does. And that suits Liman just fine.

"You don't have to understand why and how we do certain things," he told me.

Nevertheless, Liman said he does care about making scientific sense.

"I said that I was only going to take this one leap of faith," he said. "I tried to observe the laws of physics as best I could outside this one leap."

For example, Liman worked it out so that every time Christensen made a jump, the surrounding medium would whoosh in to take his place. "He has a certain volume," Liman explained. "If he's no longer there, something has to fill that space."

Another rule of the movie is that Jumpers have to enter a new reference frame with the same momentum they had when the left the previous reference frame. For example, let's say Christensen is in the middle of a fall from the top of the Empire State Building. "Yes, you can teleport away from that spot, but wherever you arrive, you will be traveling with that velocity," Liman said.

Limiting the liberties
Tegmark liked how Liman limited the liberties he took with basic physics. "He saw through things at a different level than the typical Donald Duck physics that you see," the physicist said.

"The main thing that he took liberties with was what we call energy conservation," Tegmark continued. "Einstein told us that E=mc². In other words, matter is the same thing as energy. ... That means that a modest amount of matter, like you, corresponds to many, many megatons of energy. It's no small task to eliminate that from one place and put it in another place.

"If you turned yourself into energy, it would be like a hydrogen bomb had gone off," he said.

Let's say mad scientists had unlimited energy at their disposal (bwa-ha-ha!). It might be possible to bend space-time into an extradimensional wormhole and teleport to distant locations. But that would take some expertise - more expertise than the high-school dropout in "Jumper" could muster. And there would be a high price to pay.

"If you were able to somehow create a wormhole, when you try to jump through it, it would probably turn into a black hole - which kind of sucks," said Tegmark, fully aware of the double meaning.

The real-world physics behind the possibility of wormholes has been entangled with science fiction for decades. The concept was fleshed out by Caltech physicist Kip Thorne when Carl Sagan asked him to come up with a plausible way to get his heroine back and forth through space-time in the novel "Contact." To Thorne's surprise, he found that there was nothing in physics that absolutely ruled out the existence of wormholes, as long as you could get your hands on a huge amount of negative energy.

"Wormholes are probably not stable, but we still haven't been able to prove that in a convincing way," Tegmark said, "so there's still a slight possibility that lingers. People are looking into whether you can stabilize them with dark energy."

Science fiction and science fact
Tegmark said the best thing about science-fiction movies, even movies where the science is especially fictional, is that they spark more interest in science fact.

"As a scientist, often the hardest thing is not finding the right answer, but finding the right question - and science fiction is great for generating the right questions," Tegmark told me. "It's like when you're watching a movie and you say, 'It's obvious that that's impossible.' Then you realize, it's not so obvious why it's impossible. You start asking very basic questions about the nature of space and time."

That's how Einstein started along the path that eventually led to E=mc² and more.

"It was precisely because Einstein was trying to understand the nature of time that we arrived at nuclear power," Tegmark said. "This goes to show that anything that stimulates basic research, even though it might seem completely useless, often has great applications."

So what's next? One of the fundamental issues surrounding wormholes is that they might (or might not) essentially work like time machines. There's even talk that microscopic time machines could be created later this year at the Large Hadron Collider.

That claim may be highly debatable - but Liman is already aware of the connection to time travel, which is a time-honored tradition in sci-fi cinema.

"I saved that for the sequel," Liman said. "That is definitely something that would be part of this, but it was too much for this story. I felt like it would have limited the depth to which I could explore this one idea."

To learn more about what Hollywood has done to scientific ideas over the years, check out Insultingly Stupid Movie Physics, the Cartoon Laws of Physics and the Bad Movies page at Phil Plait's Bad Astronomy Web site. If you have any other funny (or fantastical) examples of cinematic science, feel free to add them as comments below.