Some of the most reliable witnesses to the changes in the Gulf of Mexico oil spill have been satellites in orbit. A newly released NASA video traces the changes that have taken place in the spill's extent - and there's more where that came from. Much more, in terms of pictures as well as petroleum.

NASA's regularly updated roundup of Gulf spill imagery features views from two of the space agency's Earth-observing satellites, Terra and Aqua. Those two polar-orbiting probes are equipped with imaging spectroradiometers that send back data over a wide range of wavelengths. The oil on the surface shows up as a silvery sheen, glinting in the sun.

Photo by NASA

A thermal image from NASA's Terra satellite, captured on May 24, shows silvery ribbons of oil in the Gulf of Mexico reaching the very tips of the Mississippi River Delta.

Other instruments on the satellites pick up thermal imagery of the Gulf. Vegetation shows up in red, and oil on the water has a silvery look. The image acquired on May 24 highlights a mysterious dark patch of water at upper left. NASA says the dark color may indicate the use of chemical dispersants, skimmers or booms. Or it may merely reflect natural differences in turbidity, salt content or organic matter in the coastal waters.

Another NASA team has been flying above the spill in a spooky-looking airplane over the past couple of weeks, taking pictures in a different set of wavelengths. The Airborne Visible/Infrared Imaging Spectrometer, or AVIRIS, sees crude oil on the surface in shades of orange and brown.

The European Space Agency's Envisat radar satellite has been tracking the spill as well. Last week, scientists drew upon Envisat data to conclude that oil had indeed entered the Loop Current that sends water circulating around the Gulf and eventually toward Florida.

AccuWeather suggests that the oil slick is in a part of the Loop Current that has been "pinched off" to create a large eddy. That means the surface slick is swirling around in the current and not approaching Florida ... at least for now. "Stopping the leak sooner rather than later would go a long way toward reducing the threat to shorelines not yet impacted by the oil spill and reducing the damage to areas already hit," according to AccuWeather's oil-slick forecast.

It's important to remember, however, that most satellites aren't good at seeing what's beneath the surface. On that score, scientists sampling the water column aren't offering much reassurance. Researchers aboard the University of South Florida's R/V Weatherbird II said they detected a wide area of the Gulf with elevated levels of dissolved hydrocarbons. The apparent plume of pollution, which was at its highest concentration 1,300 feet (400 meters) beneath the surface, is invisible to the eye but nevertheless could represent a long-term threat to marine life.

"The ramification is that what we see at the surface is not the entire story," biological oceanographer Ernst Peebles said today in a university news release. "This is not a big glob of oil drifting. These are layers. They show up on sonar as layers with clear water in between."

The bottom line? Even if the Deepwater Horizon oil leak stopped tomorrow, the effects of the spill will have to be monitored for years or decades to come - not just from space, but from the sea.

More on the story:

• Graphic: Trace the oil spill's spread
• Oil-spill cam becomes Internet sensation
• Can mud work a miracle in the Gulf?
• Astronauts see 'scary' spill from space
• Strange beauty in an ugly oil slick
• Complete coverage of the Gulf oil spill

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We try to bring you the best pictures of the cosmos in our "Month in Space" slideshow, but no single slideshow can give you the full picture for what's going on in space.

For one thing, there's always some late additions we just weren't able to slide into the show, such as the picture of last night's Delta 4 rocket launch at right. This is an unusual launch pad view of the rocket taking off from Cape Canaveral Air Force Station in Florida, with a next-gen GPS satellite as the payload. (You can find more pictures on the United Launch Alliance's website.)

More importantly, you may be missing out on the wider perspective. Sure, the slideshow has a few images from the shuttle Atlantis' just-concluded "last mission" to the International Space Station. But lots of other information and images are available on sites ranging from NASA's Human Spaceflight Web to Japanese astronaut Soichi Noguchi's Twitpic page. Just today, NASA released a 14-minute video retrospective on the "Ice Team" inspection that preceded Atlantis' launch.

Check out my posting from a week ago for more about Atlantis imagery. And check out the links below for more about the images in our "Month in Space" slideshow, including larger versions of the pictures that you can print out or turn into desktop wallpaper.

• Swan song in space (International Space Station)
• Outburst from the sun (Solar Dynamics Observatory)
• Big and small moons (Cassini)
• Flying Seagull (Wide-field Infrared Survey Explorer)
• Oil spill stretches out (Terra)
• Japan's highest lab (International Space Station)
• Flight into the night (Picture from Arianespace)
• Two faces of a grand galaxy (Picture from ESO)
• Flooding in Tennessee (DigitalGlobe)
• Full-frontal shuttle (International Space Station)
• Ash on Mars (Mars Express)
• Storm on the sun (Solar Dynamics Observatory)
• Space snapshot (International Space Station)

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It’s no spoiler to say that this week's “Lost” finale included a surprise twist of the afterlife ... which didn’t sit too well with science-minded types. It's one thing to speculate about the arrow of time, quantum parallel universes and the chronology protection conjecture, but it's quite another to speculate on what happens when you die.

Popular Mechanics has made a regular feature out of dissecting the science behind "Lost," but the final episode offered surprisingly little to go on - as executive producer Carlton Cuse admitted to PM's Erin McCarthy: "We're doing more fiction than science these days. ... We never promised a show that was based entirely and grounded in science. It's nice that it's able to do that, but we reserve the right to go in the direction that the über-plan directs us."

McCarthy's final fact-check had to do more with duct tape than the doom that faces us all. (Bottom line? Miles shouldn't believe quite so much in duct tape.)

The fact and fiction of duct tape wasn't exactly uppermost on the mind of Berkeley physics professor Richard Muller when I chatted with him about "Lost" earlier this week. I had phoned Muller to talk about his textbook, "Physics and Technology for Future Presidents," but we ended up talking about the show because he happened to be a "Lost" über-fan. He even predicted on his website how the show would end. Needless to say, we didn't see Jacob turning into a huge white-smoke monster for a final battle with the island's black-smoke monster.

Muller found Cuse's über-plan to be über-lame. "I could not have been more disappointed," he told me. "They always had a philosophical background and some mysteries, but they threw in a whole set of mysteries that became the focus of discussion. What was the Dharma Initiative for? What were the rules? What was the purpose of the island? ... We were supposed to get answers to these questions. We didn't get any."

For example, why was Ben Linus unable to kill Charles Widmore in his bedroom, but able to shoot him dead on the island? Who set up the rules for the island, and what would have happened if the smoke monster got away? What led Ben and the Original Others to kill off the entire Dharma settlement?

Now Muller suspects that the creators of "Lost" might have been making up most of this stuff as they went along. "The last episode was so disappointing that I don't trust those guys anymore," he told me.

Fortunately, here at Cosmic Log, we don't always restrict ourselves to just the facts. In the past, we've taken on subjects such as alternate afterlives, various theories of heaven (and your reflections on the topic as well), plus out-of-body experiences (and a variety of suggested explanations). If you're a "Lost" fan with a scientific bent, feel free to weigh in with your thoughts on how the show ended ... or how it should have ended.

For a more general discussion of the "Lost" finale, check out the TODAY Television forum on msnbc.com. Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."

We're finishing up the first week for the new blog design, and although there may be a few tricks I still need to learn, the process so far has been fairly painless. One of the new features is the ability to publish "clippings" from other sources on the Web. This is a nice, easy way to supplement your daily dose of science, but it doesn't really give you a chance to comment on the links or talk more generally about what's on your mind. So I'll continue to offer a weekend roundup of Web links, just like this one. Feel free to leave comments about other reports you've seen on the Web, or weigh in with your own cosmic commentary. Regular postings will resume on Tuesday.

• The Economist: A robot in every home
• The New Yorker: What did Jesus do?
• New Scientist: Nanofoods on the menu 
• L.A. Times: Trying to predict pre-terrorism

... And a closing thought: Remember the reason for the Memorial Day season.

Two of the debutantes on the final frontier - SpaceX's Falcon 9 rocket and the Planetary Society's Lightsail 1 solar sail - will be making their debut a bit later than planned. Another space newbie, the first in a new series of GPS navigation satellites, was finally launched after a couple of technical delays.

Falcon 9: June at the earliest
The Falcon 9 is designed to carry cargo to the International Space Station for NASA at a fraction of the cost of a space shuttle flight. Someday, it may carry astronauts into orbit as well, if NASA's current vision for future spaceflight works out. As we discussed earlier this week, there are those (particularly on Capitol Hill) who worry that SpaceX and other commercial launch providers (even well-established companies such as Boeing and Lockheed Martin) won't be able to deliver safe, reliable space service. The success or failure of the first Falcon 9 demonstration could change the character of this multibillion-dollar debate.

Liftoff is set to take place at Cape Canaveral Air Force Station in Florida, but the Air Force still has to sign off on SpaceX's flight termination system - basically, the "self-destruct button" that would have to be pushed if the launch goes awry. In the meantime, the Air Force had other space matters to deal with, such as the repeated delays in the launch of a next-generation GPS 2F-1 satellite atop a Delta 4 rocket.

"Looks like the delay of the Delta IV GPS satellite launch has taken up a lot of resources at the Cape and in turn pushed the first test launch of Falcon 9 from May 28/29 to no earlier than June 2/3," SpaceX spokeswoman Emily Shanklin said in an e-mail to reporters.

That Delta 4 was launched from the Cape on Thursday night, and on Friday, Shanklin sent a follow-up e-mail saying the Falcon 9 launch date was being delayed yet again: "Due to delays in the recent GPS satellite launch, Air Force range safety officials unfortunately did not have the resources to process our final documentation. SpaceX is now looking at no earlier than Friday, June 4, for its first test launch attempt."

Space News has still more about SpaceX's anticipated launch schedule, including ... you guessed it ... more delays.

Lightsail 1: Spring of 2011 at the earliest
The nonprofit Planetary Society says that development work on its solar-sail mission "is proceeding well." Lightsail 1 is destined to be launched into an orbit 500 miles (800 kilometers) above Earth, and then unfurl an 18.5-foot-wide array of reflective plastic panels. Solar radiation should propel the sail through space like a breeze on a kite.

David Imbaratto / Stellar Exploration for Planetary Society

An artist's conception shows the Planetary Society's
Lightsail 1 solar sail in space.

The same principle is employed on Japan's Ikaros solar-sail experiment, which was launched last week and by all reports is still on track.

The Planetary Society had hoped to launch Lightsail 1 by the end of this year, but today's update indicates that the timetable has been stretched out, with liftoff now set for no earlier than the second quarter of next year. That's no surprise: The society's executive director, Louis Friedman, signaled that there would likely be a delay when I chatted with him in March.

Check out the full update for details about how Lightsail 1's design is being tweaked.

More for space geeks
This has been a big week for space week, and not just because it's Geek Week on "The Rachel Maddow Show." We had a shuttle landing on Wednesday, the House hearing on space policy ... and to top it all off, the International Space Development Conference is under way in Chicago. I'm not able to attend this year, but you can keep posted on the goings-on by checking Space Transport News, or keeping track of Twitter updates with the #isdc or #isdc2010 hashtag.

There's already talk of new X Prize space competitions - for example, to deflect potentially hazardous asteroids, or get rid of space debris, or put beamed-power technologies to new tests. The X Prize Foundation's Will Pomerantz said such concepts are indeed in the works, although nothing is yet set in stone. "These are not just ideas written down on a paper for fun," he told me. So stay tuned for more geek gratification to come.

This report was last updated at 9:45 p.m. ET May 28. Join the Cosmic Log corps by signing up as my Facebook friend or hooking up on Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."

Berkeley physics professor Richard Muller, author of the new textbook "Physics and Technology for Future Presidents," says Barack Obama could learn a lesson from the Gulf of Mexico oil spill. Using offshore oil to solve America's liquid energy security issue poses a bigger problem than previously thought, he said.

You won't find the professor's answer to the problem in the back of the book, but it can be summarized in two words: natural gas.

"The thing the president really needs to know is that we have huge supplies of natural gas; that although it's not liquid, compressed natural gas is an alternative fuel for U.S. automobiles. And U.S. policy has not taken advantage of that in any significant way," Muller told me today.

Natural-gas drilling is fraught with controversy, but in the wake of the Gulf oil spill, policymakers and energy-industry executives may well shift their focus from offshore oil to onshore natural gas, Muller said. That's not something Obama is likely to talk about when he visits the Louisiana coast to assess spill damage on Friday. He's more likely to play up his administration's new steps to go slow on offshore drilling. Nevertheless, Muller said the oil-spill crisis provides Obama with a golden opportunity to widen the debate over America's energy options.

Multiple-choice questions
Muller addresses energy policy, climate change and many other hot-button political issues in his textbook, which is an academic spin-off of "Physics for Future Presidents," a book that's geared for less scientifically inclined audiences. The 532-page textbook covers twice as much material as the earlier book, and includes all the features you'd expect from a classroom text (including multiple-choice and essay questions at the end of each chapter). Muller says the text already been adopted by 15 universities in the United States, plus another university in Pakistan.

"The strangest place it's been used [as a textbook] is actually not in Pakistan, but in San Quentin," Muller said. He's heard tales of inmates at the California prison sitting around in the exercise yard, discussing physics. "That's the one place where I guarantee there's no future president coming out," he joked.

Muller said he's heard that first lady Michelle Obama promised to pass along a copy of the book to her husband, and he's gotten feedback from "very high-level people" in the administration (though he's not naming names). He's also proud of the warm reviews that "PFFP" has received from the left side of the political spectrum (Huffington Post) as well as the right side (National Review).

"To get good reviews from both sides on issues that are as contentious as terrorism, nuclear war and global warming is very gratifying," he said. "This is stuff that Democrats and Republicans can agree on. Physics is nonpartisan."

Pros of natural gas
So here's Muller's take on post-spill energy policy:

"When you're talking about energy, there are really three issues that get confused: global warming, local pollution - that's the issue that has thrust itself in here - and liquid energy security," he said. The United States has plenty of fossil-fuel energy reserves, in the form of coal and gas, but the challenge is how to put those reserves to use, along with energy alternatives, while addressing those three key issues.

The energy industry had thought increased offshore-oil drilling could boost America's liquid-fuel supplies, even though it wouldn't really address the global-warming issue. Muller said "the crisis caused by this spill reminds us that there's another dimension to liquid fuel that is bad for the environment" - that is, the potential for pollution on a regional scale.

The way Muller sees it, compressed natural gas offers a viable alternative for fueling the nation's automobiles. The greenhouse-gas impact of natural gas consumption is slightly less than that of burning gasoline. Natural gas contains more energy per pound than gasoline, although it's not as dense. America's energy infrastructure might have to be reworked so that drivers "fill 'er up" from a natural-gas pipe rather than from a gasoline hose. Natural-gas-fueled autos might have to have a shorter range than gasoline-fueled cars. But Muller thinks the problems are solvable.

"Natural-gas automobiles are much closer to widespread use than the president's favorite alternative technology, electric cars," he said. "I believe the physics says that his alternative is a poor choice."

There's far less energy in a pound of car batteries than there is in a pound of gasoline or natural gas, even when you're talking about the high-tech batteries that go into a Tesla or a Chevy Volt. "This is not a realistic alternative for the bulk of the American people," Muller said. "It will work only for wealthy Americans."

Cons of natural gas
Natural gas is not without its own serious environmental issues: In addition to the greenhouse-gas impact, some gas-extraction companies have developed a bad reputation, as shown in the award-winning documentary "Gasland."

"What they do in order to extract natural gas is, they'll drill horizontal wells into shale, and then they'll pump water down and crack the rock [to release the gas]. You have this water that comes back up, and what do you do with it? You could clean it, but in the past the industry has not done a good job of doing that," Muller said.

Muller said he'd like to see Obama put together a study group to take a hard look at energy alternatives, building on the momentum generated by oil-spill outrage. All the options should be covered, including an intelligent approach to natural-gas drilling. "The drilling has to be accompanied by legislation that will assure that local communities can benefit, and that environmental damage will not be done," Muller said.

I'm still partial to approaches that go beyond fossil fuels - including terrestrial solar and wind, biomass, bacteria and algae, "negawatts" and nuclear, even space solar power and fusion in the long term. But Muller is correct that power portability has to be part of the equation. It'd be great to see revolutionary new battery technologies and ethanol/methanol initiatives, but maybe natural gas deserves some consideration as well, at least as a short-term alternative. What do you think? Feel free to leave your comments below.

Bonus round: I'm including four multiple-choice questions from "Physics and Technology for Future Presidents" below. Take a crack at giving the correct answers in your comment (for example, "1:A, 2:B, 3:C, 4:D"), and I'll weigh in with the answer key on Friday.

1. Which of the following contains the most energy per gram?

• A. TNT
• B. Chocolate chip cookies
• C. Battery
• D. Uranium

2. Compare the energy in a kilogram of gasoline to that in a kilogram of flashlight batteries:

• A. The gasoline has about 400 times as much energy.
• B. The gasoline has about 10 times as much energy.
• C. The gasoline has about 70 times as much energy.
• D. They cannot be honestly compared, since one stores power and the other stores energy.

3. Coal reserves in the United States are expected to last for:

• A. Hundreds of years.
• B. Three or four decades.
• C. 72 years.
• D. Less than a decade.

4. The efficiency of inexpensive solar cells is closest to:

• A. 1 percent.
• B. 12 percent.
• C. 65 percent.
• D. 100 percent.

Update for 4 p.m. ET May 28: I've added the book's answers to the questions as a comment below (#32).

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Illustration by AP

Click for interactive: Drilling mud is being pumped into equipment at the bottom of the Gulf of Mexico in hopes of cutting off the flow of oil. Click on the image to explore an interactive graphic.

Never have so many hopes rested on so much mud: The "top kill" maneuver that got under way today is the latest best strategy for cutting off the catastrophic Gulf of Mexico oil spill. And the key to the top kill is millions of gallons of a viscous fluid known as drilling mud.

This mud is not your garden-variety sludge: It's an industrial-strength blend of water and minerals, generally including an absorbent, slippery kind of clay known as bentonite. Drilling fluid is used for a wide variety of purposes in oil fields - as lubricants, coolants, drill cleaners or hole fillers.

That last application is how it's being used in the Gulf: As shown in this interactive graphic, gallons of heavy, gloppy drilling mud are being pumped into the half-broken blowout preventer on top of the wellhead.

The idea is that the dense fluid will eventually press down on the oil rising from thousands of feet below and clog up the oil line. This posting on the Oil Drum forum compares it to trying to get your basement drain to back up. Another way to think of it is like ketchup that has a hard time blurping out of the bottle.

The BP oil company, which is still responsible for cleaning up the Gulf mess, has laid in 50,000 barrels (2 million gallons) of drilling mud for the job. The pumping operation began this afternoon, and as of this evening's news conference, BP chief operating officer Doug Suttles said more than 7,000 barrels had been pumped in.

"The job has been proceeding as planned," Suttles said.

BP executives have estimated that this latest strategy has a 60 to 70 percent chance of working. The problem is that the mud has to fill the blowout preventer and sink down into the well, counteracting the pressure of spurting oil. That pressure might be so great that the mud is pushed out of the leaking pipes as fast as it can be pumped in. There's even a chance that the drilling mud will ream out the contraption's partially closed valves, opening the lines to create an even bigger oil gusher at the bottom of the sea.

In the aftermath of the Persian Gulf War, oil wranglers like the late Red Adair used the top-kill strategy to stop up sabotaged oil wells in Kuwait - but doing it using robo-submarines a mile beneath the ocean surface is something completely different. Will Red Adair's successors pull this one off?

If this doesn't work, you can forget the top kill and start thinking about the next strategy, known as the lower marine riser package or LMRP Cap Option. That involves cutting off the top of the blowout preventer and putting a cap on top to suck up the oil. This slide presentation provides a graphic look at BP's next steps, and this BP video provides a technical overview.

More about oil-spill strategies:

• What the heck's a 'top kill'?
• Live video: Streaming view of oil leak
• Animation: How the top kill works
• Oil dispersants spark worries

Update for 12:50 a.m. ET May 31: The top-kill effort didn't work, and BP is moving on to the LMRP Cap Option.

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For the second time this month, NASA's chief faced tough talk on Capitol Hill from lawmakers - as well as from Apollo moonwalkers Neil Armstrong and Gene Cernan, plus longtime aerospace executive Tom Young.

Both astronauts told members of Congress that returning humans to the moon was not only desirable, but necessary for future exploration - even though NASA says it's no longer a priority.

To some extent, today's House Science and Technology Committee's hearing was a reprise of the Senate hearing earlier this month, where Armstrong and Cernan played the starring roles. If anything, NASA Administrator Charles Bolden and the White House's revised exploration vision came in for even harsher scrutiny.

"By now you probably have figured out that this committee is not with you," Rep. John Garamendi, D-Calif., told Bolden. The administrator said he was getting that message.

NASA vs. Congress
The main themes of the criticism are that NASA should keep going with the Constellation program and not rely on buying launch services from commercial providers. Constellation calls for the development of new NASA rockets, starting with the solid-fueled Ares 1, to service the International Space Station and eventually return to the moon.

The White House's budget proposal calls for the cancellation of Constellation, while going ahead with the development of some of the hardware, such as a scaled-down Orion crew capsule for emergency rescue and a heavy-lift rocket for trips beyond Earthorbit. The Obama administration sided with an independent panel's report concluding that the original Constellation budget and timeline were wildly unrealistic.

When the space shuttle fleet is retired, late this year or perhaps sometime next year, NASA would buy rides to the space station through at least 2020 - first from the Russians, then from private companies potentially ranging from Boeing, Lockheed Martin and Orbital Sciences to new entrants such as SpaceX.

Bolden told lawmakers that the Orion Lite capsule, currently known as the Crew Rescue Vehicle, could be ready for flight in the 2013-2015 time frame, at a cost of $4.5 billion. He said a revised development plan would be ready for review next week. The NASA chief acknowledged that it would be cheaper to pay the Russians for Soyuz rides, but "cheap is not what we're looking for ... we're looking for domestic capability."

Few in Congress are happy about the shift away from Constellation, and in fact current law forces NASA to keep going ahead with the program until Congress says otherwise. Bolden repeatedly acknowledged that point during the hearing. But under questioning, he also acknowledged that the program's manager, Jeff Hanley, was being reassigned to another position as deputy director for strategic plans at NASA's Johnson Space Center. Hanley took a high profile in planning continued testing for Constellation hardware. (NASA Watch has Hanley's brief farewell e-mail.)

Lawmakers worried that canceling Constellation would leave the United States in a "Third World category in spaceflight" (said Rep. Lincoln Davis, D-Tenn.) ... would represent a "U-turn" from the vision laid out five decades ago by President John Kennedy (said Rep. James Sensenbrenner, R-Wis.) ... and would leave the country's aerospace workforce "completely demoralized."

"Heck, I'm demoralized just looking at it," said Rep. Donna Edwards, D-Md.

Astronauts vs. NASA
Armstrong, Cernan and Young were similarly downbeat. Their written statements, along with Bolden's, are all available through the House committee's website. Here are some highlights:

Neil Armstrong, who became the first man to walk on the moon during Apollo 11 in 1969, took particular aim at President Barack Obama's statement that NASA should pass up human flights to the moon because "we've been there before":

"Some question why America should return to the moon. 'After all,' they say, 'we have already been there.' I find that mystifying. It would be as if 16th-century monarchs proclaimed that 'we need not go to the New World, we have already been there.' Or as if President Thomas Jefferson announced in 1808 that Americans 'need not go west of the Mississippi, the Lewis and Clark expedition has already been there.'

Armstrong touted the moon as a test bed for longer trips, a scientific destination in its own right, and a potential resource for exotic materials such as helium-3 fusion fuel and palladium-group metals. When Rep. Ralph Hall, R-Texas, asked whether returning to the moon was "a nice-to-have or a need-to-have," Armstrong answered, "It's both, sir."

Gene Cernan, who was the last man to walk on the moon during Apollo 17 in 1972, largely reprised his "Mission to Nowhere" testimony from the earlier hearing. He surmised that the originators of the revised policy were promoting their own agenda rather than that of NASA or Congress:

"With the submission of the FY2011 budget, the administration and the originators of this proposal were either misinformed or showing extreme naivete, or I can only conclude are willing to take accountability for a calculated plan to dismantle America's leadership in the world of human space exploration, resulting in NASA becoming nothing more than a research facility. In either case, I believe this proposal is a travesty which flows against the grain of over 200 years of our history and, today, against the will of the majority of Americans."

Tom Young, a retired Lockheed Martin executive, recapped NASA's legacy in human spaceflight and said the proposed move to a more commercial way of exploring space "will be devastating" for that legacy:

"A fundamental flaw in the proposed human spaceflight program is a commercial crew initiative which abandons the proven methodology I have described. NASA's role is reduced to defining safety requirements and general oversight. An argument for pursuing this new human spaceflight approach is that the proven methodology is too expensive. This same rationale caused the Air Force and NASA to try similar approaches in the 1990s. ... The results were devastating, and the adverse impact is still with us today. ... On average, programs implemented using this approach resulted in half the intended program for twice the cost, and they were six years late on average."

Young pointed to examples ranging from cost overruns on the NPOESS weather satellite program (managed by Northrop Grumman) to the failures of NASA's Mars missions in 1999 (managed in part by Young's own Lockheed Martin). Back in 2000, Young defended NASA's "faster, cheaper, better" approach, but he apparently has since changed his mind.

The other side of the issue
Rep. Dana Rohrabacher, R-Calif., noted that the list of witnesses wasn't exactly balanced. "We have not received both sides of this issue at all ... I'm just saying, there is another side," he told panel chairman Bart Gordon, D-Tenn.

Gordon noted that Bolden had spent a long time defending the new policy, that White House science adviser John Holdren had been asked to attend but couldn't show up ... and that several individuals and groups had sent letters to the committee in support of the policy. Chief among those are Buzz Aldrin, Armstrong's Apollo 11 crewmate on the moon; and Apollo 9 astronaut Rusty Schweickart. For years, Schweickart has been trying to draw attention to the threat posed by near-Earth asteroids, and he particularly likes NASA's new emphasis on asteroid exploration.

He's not the only one: One of the few bright spots in the testimony came when Rep. Kathy Dahlkemper, D-Pa., said she was excited about the idea of going to an asteroid. Bolden said that NASA was making plans for a robotic landing on an asteroid by 2016, using an experimental Hall thruster system - leading up to a crewed mission by 2025.

"When a kid sees something rendezvous with an asteroid in 2016, let me tell you, they're going to be excited," Bolden said.

But it was clear from the tenor of the hearing that NASA's space vision will likely go through another revision before NASA approves $19 billion in funding. When Rohrabacher worried that Congress was rushing to judgment, Gordon told him, "You can be well assured that we are not one hearing away from an authorization." And even Bolden seemed to hint that NASA still has plans for the moon.

"We're going to take incremental steps to leave low Earth orbit. ... The steps are International Space Station, the moon and asteroids, and eventually Mars," Bolden said.

So what's the best way to boldly go? Or is the trip beyond Earth orbit worth all the money, risk and aggravation? Feel free to weigh in with your comments below - and if I come across the letters from Aldrin, Schweickart or others who corresponded with Congress, I'll make sure to link to them here.

Bonus round: Sen. Bill Nelson, D-Fla., told Obama today in a letter that he intended to include money for an extra shuttle flight in the NASA reauthorization bill. The mission would kick in if the shuttle Atlantis, which landed just today, is not needed as a rescue vehicle for the current "last shuttle flight," scheduled for launch in November or later. The scenario would be what NASA planners (and Nelson) have been discussing for weeks: a space station resupply flight in the summer of 2011 with a pared-down crew of four astronauts aboard. "I look forward to working with you to make this important mission a reality," Nelson wrote.

Correction for 4:25 p.m. ET May 26: For a while there I had the wrong party affiliation for California Republican Dana Rohrabacher.

Update for 5:50 p.m. ET May 26: Buzz Aldrin's letter to the committee says NASA's revised space plan is "a rich vision that I would hope that we could all embrace." He said he shared the concern voiced by Armstrong and Cernan about a gap in America's access to space, and he called for Obama to issue an executive order requiring NASA and the Air Force to work together to modify existing expendable rockets for human-rated flights. He also called for the development of a new space glider that could be launched atop such rockets.

Rusty Schweickart's letter says NASA was "on a dead-end road ... a path to nowhere." Going back to the moon wouldn't be ambitious enough, in Schweickart's view, while going straight to Mars would be too ambitious. Schweickart touted sending astronauts to a near-Earth asteroid as "an intermediate Mars trajectory which, in my opinion, makes much more sense." He also supported shifting more responsibility to the private sector to support "the development of an independent, private, commercial capability with a huge upside potential for jobs and, indeed, world industrial leadership."

Correction for 9 p.m. ET May 27: I originally wrote "$4.5 million" for the cost of building the Orion Lite vehicle, but of course the cost estimate is actually $4.5 billion. Thanks to Cosmic Log correspondents for setting me straight. I think I'll blame this one on the new publishing system. ;-) I've also received and posted PDF copies of the letters sent to the committee by the Planetary Society and a group of science and space organizations in support of Obama's space policy.

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NASA may have put its plans to send people to the moon on hold, but that doesn't mean robots can't go.

Today, XCOR Aerospace and Masten Space Systems announced they were teaming up to develop robotic landers that could go to the moon, to asteroids, to Mars or anyplace else NASA wants them to visit.

It's an interesting pairing: Masten has been working on vertical-takeoff lunar lander prototypes for years, and last year the Masten team won more than $1 million of NASA's money in the Northrop Grumman Lunar Lander Challenge. XCOR has worked on a methane-powered rocket engine for NASA, and is currently focused on building a series of horizontal-takeoff rocket planes that could eventually go to the edge of space.

XCOR's chief executive officer, Jeff Greason, was an outspoken member of the independent panel that laid out NASA's options for future space exploration - including the "flexible-path" option that the White House eventually chose. That option calls for the cancellation of NASA's Constellation back-to-the-moon program, and proposes instead that the human spaceflight program should look first toward lower-gravity destinations such as asteroids and Martian moons.

You'll probably hear a lot more about the rightness or wrongness of NASA's revised vision on Wednesday, when moonwalkers Neil Armstrong and Gene Cernan testify at a House committee hearing. Armstrong and Cernan struck sparks earlier this month when they criticized the new space policy at a Senate committee hearing.

That debate doesn't directly affect what NASA does with its robotic exporation program, however. XCOR and Masten said they expect NASA to go forward with a series of unmanned lander projects. "These automated lander programs are expected to serve as robotic test beds on Earth, on the lunar surface, Mars, near-Earth objects and other interplanetary locales, helping NASA push the boundaries of technology and opening the solar system for future human exploration," today's announcement says.

These two "New Space" companies aren't the only ones looking for lander business, however. You can bet that the competitors will include the same companies that have worked on landers for the moon and Mars in the past: Lockheed Martin, the Boeing Co. and Northrop Grumman. Other companies could enter the fray as well.

For example, some folks have been talking about a NASA-developed "Project M" that would send a humanoid robot to the lunar surface. Clark Lindsey at Space Transport News points out that the Johnson Space Center engineers responsible for the Robonaut project have detailed their Project M concept in a white paper posted to their website. The paper says a prototype lander has been assembled and is to undergo free flight testing as early as this month. The company that is helping develop the prototype is none other than Armadillo Aerospace, which vied against Masten in last year's Lunar Lander Challenge and may compete with XCOR for space tourism dollars.

This could get interesting, especially when you consider that 21 other private-sector teams are also shooting for a moon landing as part of the $30 million Google Lunar X Prize competition. And then there are the Chinese, and the Indians ...

Who's up for a robotic moon race?

A laser scanning team has just finished up work on Mount Rushmore, kicking off the latest phase of a project to create a digital record of the world’s great monuments.

Two weeks of arduous 3-D scanning wrapped up just today, said Elizabeth Lee, director of projects and development for California-based CyArk. "It was a really successful project," she told me. But it wasn't without its challenges. Rope teams had to clamber down the face of the mountainside in South Dakota's Black Hills to record the ins and outs of the 60-foot-long presidential faces.

The weather didn't help. "We had everything," Lee said. "We had 90-degree heat, where people got sunburned. We had snow that kept us from working for two days. Yesterday, there were hailstorms and floods and tornadoes."

But it's all worth it: When all the readings are compiled, the partners in the project - including the National Park Service - will have the most accurate virtual rendering ever made of the decades-old monument.

Between 1927 and 1941, the faces of Presidents George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt were sculpted by hundreds of workers using dynamite and chisels. This time around, the workers had to take care not to chip away at the rock. In addition to using more traditional surveying techniques, Lee and her teammates set up laser-scanning equipment on custom-made tripods, and bounced laser light harmlessly off the sculpture's nooks and crannies. CyArk explains how laser scanning works in detail.

During today's final round of measurements, a tripod was positioned on Washington's eyebrow and just above his chin to scan the parts of the face that couldn't be accurately measured from the ground or from the top of George's head, Lee said.

The product of all this work will be a high-definition 3-D computer representation of the famous faces. The park service can use the database to create picture-perfect representations of Mount Rushmore for scale models, online virtual tours and perhaps a holographic display at the visitor center. And in case anything happens to the monument - ranging from normal wear and tear to a catastrophic crumbling - the 3-D data can be used to guide repairs.

CyArk sees the Rushmore project as part of its grand plan is to create virtual records for 500 heritage sites around the world in five years. "We haven't set an official start date yet," Lee said. Nevertheless, the venture is getting an early start toward the 500-site goal by carrying out more than 30 preservation projects at places ranging from Angkor Wat to the ancient Egyptian capital of Thebes to San Francisco's Presidio.

Lee said CyArk is the brainchild of engineer/entrepreneur Ben Kacyra, who immigrated to the United States from Iraq in 1964 and helped develop the 3-D laser-scanning technology that was used on Mount Rushmore. In the past, laser scanning has been put to use in such applications as "Star Wars" anti-missile systems and oil-prospecting operations. Kacyra is using some of his fortune to show that "the technology that he developed could be used for heritage purposes" as well, Lee said.

In an Associated Press interview, Kacyra said he was pleased to see Rushmore added to the laser-scan list. "Being an immigrant, the monument is a symbol that I cherish," he said. "It's a symbol for the U.S., and a symbol for the world."

Rushmore was CyArk's first international project done in collaboration with the "Scottish 10," a heritage-mapping effort that involves Historic Scotland and Glasgow School of Art. There are still more groups out there scanning history. Here are just a few of the latest adventures to come to light:

• Nottingham Caves brought to you in 3-D
• Maya civilization mapped in a matter of days
• Virtual Romanesque monuments created in Spain
• Sue the dinosaur gets scanned by Chicago police

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You're looking at the first Cosmic Log redesign in four years, incorporating new features adapted from Newsvine, one of our cousins in the MSNBC Digital Network. This reloaded log has all the features you're used to on msnbc.com's Weblogs, plus added options for presenting video and images.

You can sign up for e-mail alerts when new items are posted, something we've been struggling to offer for the past eight years. There's also a "Share" feature for each item that lets you pass along Cosmic Log links to your friends via e-mail, Twitter or Facebook.

To see more of any item, just click the "Show More" label (which I hope you've figured out already). To read comments, just click on the link in the blue box at lower right. We've converted the past four years of posts and comments to the new system, and because of the transfer process, those items have to be frozen in time. But if you have any lingering thoughts about past posts, feel free to leave them on this inaugural new-look item.

To get the ball rolling, here are some of the comments that fell into the gap between the old and the new:

On the BP oil mess:

Mespilus, 5/24/2010, 11:18 p.m.: How does the idea of cooling off on a nice oil soaked beach with dead birds, fish, and petro fumes sound? BP executives likely live in London. In common with their big corporate and banker cadres, they have already been massively paid out as a reward for cutting corners. They could care less if they destroy a fixed asset like BP, or the Gulf of Mexico for that matter. If you have been to London recently, you may notice a baby boom . The CEOs and bankers made huge bonuses of late, and went home like stallions. Meanwhile, the rest of us were too busy arguing whether the earth is flat to notice we were being robbed.

Les Auckland, New Zealand, 5/25/2010, 4:47 a.m.: Have an inflatable seal attached to the out side of a hollow tube. Insert the tube into the leaking pipe, inflate the seal. The oil can then flow up the new tube to be pumped or capped off. Use high pressure air line and compressor to inflate the seal. Once a permanent solution is found the seal can be deflated and removed. I wish them good luck.

Gaetano Marano, ghostNASA.com, 5/25/2010, 7:44 a.m.: Why doesn't the US government send their US NAVY to do the right job quickly and STOP this "American Chernobyl"??? the FAST and EASY ways to STOP the oil spill: http://bit.ly/c8y9GX

On the supernova with a blue bullet:

Lots of Cosmic Log correspondents noted that the supernova remnant N49 is 14,000 light-years away from Earth, and that implies that any photons we're seeing from that locale began their trip 14,000 years ago. When I said that "the blast as we see it today was created by the collapse of a massive star 5,000 years earlier," I glossed over the light-travel-time angle. I thought I was being clever in my sentence construction, but it looks as if I should have addressed the 14,000-year factor anyway. Some of the comments refer to Steve Smyth's questions about what is happening to all the objects in the exploding cloud:

John F., 5/24/2010, 11:57 p.m.: So much for the speed of light, eh?

Patrick Bishop, Caldwell, NJ, 5/24/2010, 11:57 p.m.: Looks kinda like a cube.

Larry Williams, San Bernardino, Calif., 5/25/2010, 12:05 a.m.: ... The statement reads a little bit confusing. Since the blast is 14,000 light years away shouldn't it read '19,000 years earlier', otherwise how could we see it?

Jim D. in WPB, FL, 5/25/2010, 12:28 a.m.: Alan ... always interesting. Thanks.

Greg Manning, 5/25/2010, 12:49 a.m.: Steve, while it does kindle the imagination wondering if such a widespread event would be felt locally, it really most likely was not even noticed by any one of those stars or the orbiting planets, if any. Blast force from the expanding gases would have dispersed within a few light-years of the blast itself to an almost negligible amount.

As those gases passed through most of those systems, it was so widespread, and simply riding on momentum at that point, that the particles themselves may be quite distant from one another. But when viewed from this kind of distance, the whole can be seen. Much like the "forest for the trees" saying.

While the visible gases probably passed fairly harmlessly through the star systems in its expansion, the picture's depicted X-ray radiation wouldn't have even had that much effect on the objects it encountered in its expansion. Of more concern to nearby stars that may have been in a straight line on whatever axis it happened: The gamma burst of the supernova would have been devastating to any life-bearing planets in the path.

Steve, 5/25/2010, 1:07 a.m.: If the Earth were ever in the path of a gamma-ray burst from such a source, the planet would be bathed in a blindingly intense light that would basically vaporize everything in very short order. Given the vast distances in our galaxy, let alone in the universe, this particular cosmic event, cosmically speaking, is almost in our back yard.

Sanescience, 5/25/2010, 2:11 a.m.: Alien civilizations shooting at each other.

Michael Makris, Los Angeles, 5/25/2010, 2:39 a.m.: Steve, I think the bright spots you're referring to are stars in the background just shining through the cloud.

Doug Baker, 5/25/2010, 3:12 a.m.: Well, first you have to understand you watching something that happened 14,0000 years ago, that is based on the distance away and how fast x-rays and other wavelengths can travel. both travel about at the speed of light, c, or about (3 x 10 8 m/s). These these don't just happen in a very short time. So the next time, it should look very much the same. We really can never see what is happening now, which is a bit of a mind bender.

Nelson, Fort Lauderdale, FL, 5/25/2010, 9:41 a.m.: So, these ionized gases are moving away from the rest of the cloud at just under 1 percent of the speed of light. Are there other anomalies like this already traveling around, pushed forth by supernovae that occurred millions of years ago? If this is more common, this could be a great way to hitch a ride to the stars, or at least to get a heck of a boost along the way. The old solar sail back in action!

Tom, Warner Robins, GA, 5/25/2010, 10:17 a.m.: Do the math. If the star collapsed, and it is 14,000 light years away, the collapse has to be at least 14,000 years ago, not 5,000 years ago. Remember, whether it is light or X-rays, its travel speed is "c," the speed of light.

Eric, Salinas, CA, 5/25/2010, 12:14 p.m.: Awesome article, Alan! Wow, what great new discoveries our astronomers are making with our space telescopes. Really interesting how there's a neutron star or magnetar inside that supernova remnant that's shooting out those X-rays and gamma-rays. A really beautiful picture for sure. I'll be waiting eagerly for more eye-popping cosmic eye candy!

David, Boston, 5/25/2010, 12:29 p.m.: Are the gamma rays heading our way? How much time does planet Earth have? Are there caves deep enough to protect us? This is some scary stuff, this could be what happened to Mars.

MikeyMike, 5/25/2010, 2 p.m.: "Bullet the blue sky-y, bullet the blue!" - U2

David Bush, 5/25/2010, 3:04 p.m.: This thing is moving at 44.7 percent of the speed of light? How large is it and what is it composed of?

On the planets gone wild:

ccAudi, 5/25/2010, 12:02 a.m.: 44 light years away with a wobble here and a wobble there, we infer a bizarre planetary system with gigantic planets orbiting and amazing velocities. It's Ptolemaic, if you ask me.

General Omar Windbottom, 5/25/2010, 1:06 a.m.: If most planets are captured rather than "born" in situ, then these results would be the expected phenomena. We suffer from addiction to the Laplace formation scenario. Hard to move on from old paradigms.

Aurelian, Bidulescu, Atlanta, GA, 5/25/2010, 9:06 a.m.: So, Alan, in the end maybe we will conclude that Earth might very well be the center of the universe (or, at least, of our planetary system) if we consider Venus a dwarf star from a different planetary system that interacted long time ago with ours. It will become evident that the Earth is kind of in the middle between the Sun and this "initial Sun" - Venus, isn't it? Is my rationale/speculation correct? Venus has an odd (inverse) rotation around the Sun. If the astrophysics specialists will agree on this (in 300 years?!), it will help explain better the evolutionary biology, and finally reconcile Science and Religion, ha. Your thoughts?

BigDog, 5/25/2010, 9:06 a.m.: We think we know everything, but we do not know, what we do not know, just a thought about what do we really know, really very little.

Dan Hines, Concord, NH, 5/25/2010, 10:06 a.m.: So is it possible we have a similar object in our solar system on a highly inclined orbit which from time to time will cause ice ages, pole shifts and mass extinctions?

Scott, Scottsdale, AZ, 5/25/2010, 12:10 p.m.: Actually, the current model for what constitutes a planet only applies to our own solar system, so when you hear talk about exoplanets they are sticking with the old model of "if it orbits around a star but isn't a star." When we can know more about them and image them better we will be able to come up with a standard definition of what constitutes an exoplanet.

AG, Raleigh, NC, 5/25/2010, 12:53 p.m.: [You say,] "But in recent years, more off-kilter worlds have been discovered in our own solar system." What new worlds have been discovered in our solar system?

I should have provided a link to more information about the off-kilter dwarf planets in our own solar system, including Eris, an icy world that is bigger than Pluto, with a more eccentric orbit and a higher inclination (44 degrees, compared with Pluto's 17 degrees).

John Moorefield, Ohio, 5/25/2010, 2:49 p.m.: Ahh, poor Pluto, forever misunderstood.

On Atlantis' "last mission" and the future of America's space effort:

Frank Glover, Rochester, NY, 5/25/2010, 11:43 a.m.: [Responding to comment:] "I'm really surprised that someone like Bill Gates hasn't just bought up Lockheed/Martin and Boeing and McDonnell/Douglas and started his own private Space Industry."

Why? Assuming they're for sale, or that he could afford a controlling interest in both (even his pockets aren't infinitely deep, and he has his own stockholders to answer to) Bill Gates is not an aerospace guy. He's sticking to what he knows...

(Yes, I know Elon Musk and John Carmack weren't either, they also come from the software/Internet world. But they [especially John] were also willing to take the time to dig in and learn, and do it themselves. If Bill's not interested, that's okay. It *takes* people who really want to see it happen, even if their return is way down the line.)

A long follow-up on evolution and the volcano:

Sunni Poptart, Simi Valley, CA, 5/25/2010, 11:36 a.m.: @Joseph, sorry, but your reasoning of a day as 24 hours is plain wrong. If the earth and the sun were not formed how, can there be 24 hours in a day? Based on this cold hard fact your reasoning is flawed. If God doesn't live on the earth how can his day be 24 hours, just some common sense, a day is 24 hours because it takes the earth 24 hours to rotate on its axis. There are 265 days in the year because that is the amount of time it take for the earth to circle the sun. A day is the amount of time it takes for a planet to complete a full rotation on its axis, a year is the amount of time it takes for a planet to rotate around its sun. How else are we supposed to interpret a day, I certainly don't know of another way, do you? For you to claim my interpretation of a day for God to be loose is pure stupidity and a convenient denial of plain cold hard facts.

And just to clarify, Jesus' death and resurrection is symbolic in my belief. Like I said, I don't believe in the Bible. You may, but I don't. I believe in cold hard facts, the Bible is full of magic. I don't deny that there is a historical basis for some of the stories in the Bible but like any story written by man it is embellished for reaction and the masses.

You don't understand my train of thought because I go by facts, I reason things out. I cant believe in magic. I cant apply humanistic emotion to a supposed super being. My interpretations are based on reading the Bible and breaking what is in the Bible down to fact in the real world. You can warn me all you want but I will continue to believe as I do, I will continue to break down what's in the Bible and point out all the contradictions, how facts of the real world do not support the Old Testament's creation of the earth.

I do have a question for you. Since you believe that God is all knowing and Omnipotent and doesn’t have to follow any rules, how can we as his "Children" have free will? We cannot have free will if he is Omnipotent and all Knowing, because he will already know what we will do, what sins we will commit and if we will end up in the proverbial Fire and Brimstone Pit. Can you explain that to me?

@Darrah, Actually I do understand why they post here, they think they have an obligation to "Save" people and bring them to God, I was raised in a Christian Household so I have read the Bible and I know all about the stories, beliefs, etc. What turned me off to religion finally was a cultlike church that was more concerned with Tithing then your salvation. That and the fact when you analyze the Bible's version of God to be this vengeful God that will smite you if you don't join his club and follow the rules seems way too humanistic to me. How can a being that is supposed to be omnipotent and so far above us have petty human emotions? The Bible is all about Control through fear, and if history has taught us anything this is manmade and the method mankind has used to enslave and control other humans all through history.

For myself, I wish I could be deluded to believe in a fairy tale but I can't. I am the type of person to face the facts and not bury my head in the sand. If one were to truly analyze the Bible and ask hard questions, much of the Bible's scripture starts to make no sense. And the kicker is that "Christians" believe that any other religion and its followers are heretics and that their religion is a false one. The is in the face of the fact that there are religions that predate Christianity and Judaism (Old Testament Bible) Which is another reason why the Bible is a book written by man. What happened to all the people that were around before Judaism?

Why did it take God so long to "Write" the Bible? Why couldn't God get the Bible right the first time (as in New Testament being geared more toward a peaceful God)? Anyway, I just wish people could leave religion out of Science, but then again I wish I would win the lottery, but that isn't going to happen anytime soon.

To wrap all this up, Gaetano Marano is already getting nostalgic about the old look:

Gaetano Marano, ghostNASA.com, 5/25/2010, 2:19 p.m.: Why change? The current look is the best on the Web!

What do you think? One thing about the new commenting system is that I'm going to have to rely on all of you to help flag comments that are out of bounds. Are there other improvements we can make, or fresh glitches we can fix? Let's hope we all have the serenity to accept the things we cannot change, the technical capability to change the things we can ... and the wisdom to know the difference.

NASA / CXC / Penn State / STScI / UIUC

This image of the supernova remnant N49 combines optical observations (in yellow and white) with an X-ray view (in blue). Labels indicate the supernova point source toward the upper left as well as a speeding "bullet" of debris at lower right.

The stringy leftovers of a stellar explosion in the Large Magellanic Cloud make up one of the most photogenic blast scenes in our cosmic neighborhood. In the past, astronomers have used the Hubble Space Telescope and the Spitzer Space Telescope to create classic pictures of the supernova remnant known as N49, 14,000 light-years away in the constellation Dorado. Now the latest picture from NASA's Chandra X-Ray Observatory has picked up something extra: a "bullet" zooming away at about 5 million miles an hour.

The X-ray readings were gathered during more than 30 hours of Chandra telescope time by a research team headed by Penn State University's Sangwook Park. The bullet-shaped blob was spotted moving away from a source indicated in the photo above. That point source is thought to be a soft gamma-ray repeater, perhaps a neutron star with a strong magnetic field that is firing bursts of gamma rays and X-rays.

The new Chandra observations, unveiled today at the American Astronomical Society's spring meeting in Miami, suggest that N49 was a highly asymmetric explosion. Researchers surmise that the blast as we see it today was created by the collapse of a massive star 5,000 years earlier, and packs about twice as much energy as the typical supernova.

Check out the details from the Chandra team, and stay tuned for more cosmic eye candy as the AAS meeting continues this week.

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

• Bad Astronomy: Lunar boulder hits a hole in one
• Independent: Peru pyramid linked to copper industry 
• Popular Science: Cyber-map charts top Twitterati
• The New Yorker: Oil shocks

McDonald Observatory / U. Texas

Click for video: A graphic shows the star Upsilon Andromedae with lines tracing the orbits of three planets. Two of the outer planets have orbits that appear to be inclined about 30 degrees with respect to each other, astronomers say. Click on the image to watch an animation.

For decades, Pluto has been seen as an oddball in the planetary tribe - in part because its orbit was so much more eccentric and tipped than those of the big planets. But in recent years, more off-kilter worlds have been discovered in our own solar system. And today, astronomers are reporting that they've detected planets much bigger than Jupiter that are way more out of whack than Pluto.

Maybe Pluto, which was discovered by former Kansas farmboy Clyde Tombaugh 80 years ago, isn't so weird after all.

"We're not in Kansas any more as far as solar systems go," Barbara McArthur, an astronomer at the University of Texas' McDonald Observatory, said at a news briefing today.

McArthur and her colleagues - including Fritz Benedict of the McDonald Observatory and Rory Barnes of the University of Washington - reported their findings at the American Astronomical Society's spring meeting in Miami. They're also publishing a paper in the June 1 edition of The Astrophysical Journal.

This latest twist in planetary science is based on a combination of ground-based telescope observations and data from the Hubble Space Telescope, focusing on a yellow-white dwarf star called Upsilon Andromedae.

Working out the wobbles
Astronomers have known for years that three Jupiter-type planets orbit the star, which is 44 light-years from Earth and just a bit younger, brighter and more massive than our sun. They knew that on the basis of slight back-and-forth gravitational wobbles that were detected in the star.

But they couldn't know just how tipped those orbits were until Hubble joined the case. The space telescope's Fine Guidance Sensors were trained on Upsilon Andromedae to make ultra-high-resolution measurements of the star's up-and-down, side-to-side motion. Combined with the back-and-forth data, astronomers could figure out precisely how the planets' gravitational pulls jostled the star in three dimensions.

There were a couple of surprises: First of all, two of the outer planets were inclined by 30 degrees with respect to each other. Those are much odder orbits than Pluto's, which is tipped "only" 17 degrees from the solar system's main plane.

The fact that the planets are tipped meant that their mass had to be recalculated. Astronomers now estimate that the two planets (known as Upsilon Andromedae c and d) are 14 times and 10 times more massive than Jupiter, as opposed to the previous estimates of two and four times as massive. The new findings actually shifted the mass estimates so that c turned out to be weightier than d, rather than the other way around.

Upsilon Andromedae d is so massive that Benedict said it might be considered a failed star rather than a giant planet. "It's a brown dwarf in a bona fide planetary system," Benedict told me in an e-mail.

To top it off, there were hints that a previously undetected fourth planet, dubbed Upsilon Andromedae e, is orbiting the star much farther out. (The innermost planet, Upsilon Andromedae b, is thought to be two-thirds as massive as Jupiter but could be bigger if its orbit is inclined as well.)

Explaining orbital oddities
How did the orbits of planets c and d get so far out of whack? That question poses a challenge for theories of planetary-system evolution.

"Most probably Upsilon Andromedae had the same formation process as our own solar system, although there could have been differences in the late formation that seeded this divergent evolution," McArthur said in a news release. "The premise of planetary evolution so far has been that planetary systems form in the disk and remain relatively co-planar, like our own system, but now we have measured a significant angle between these planets that indicates this isn't always the case."

McArthur and her team suggest that a violent event occurred to disrupt the planetary order. Perhaps some planets gradually moved inward. Planets may have pushed each other around through gravitational interaction. And one of the most likely suspects is a nearby companion star - a red dwarf that's dimmer and less massive than the sun.

"Our dynamical analysis shows that the inclined orbits probably resulted from the ejection of an original member of the planetary system," Barnes said in the news release. "However, we don't know if the distant stellar companion forced that ejection, or if the planetary system itself formed such that some original planets were ejected. Furthermore, we find the revised configuration still lies right on the precipice of stability: The planets pull on each other so strongly that they are almost able to throw each other out of the system."

McArthur said little is known about the companion star. It appears to be thousands of times farther away from Upsilon Andromedae than Earth is from our own sun. But it may have a highly eccentric orbit that brings it close enough to send planets scrambling.

Astronomer Philip Armitage of the University of Colorado at Boulder, who was not involved in the research, said the findings support the view that "forming planetary systems are often overcrowded, if you like." As time goes on, the alien planetary system may settle into a configuration that's not so out of whack. But some oddballs might hang around even then. Thanks to Pluto and the other dwarf planets, we know that's the case in our own solar system.

Although McArthur and her colleagues say the Upsilon Andromedae system is just on the edge of instability, they expect planets c and d to stay put in their oddball orbits. What's more, Barnes told me in a follow-up phone call that it'd be "pretty unlikely" if it turned out that the first measurements of orbital inclination were made using a wildly anomalous example. Having off-kilter orbits may be the norm for planetary systems.

"Our solar system could be an outlier," Benedict chimed in.

The study demonstrates once again that as astronomers learn more about alien planetary systems, they're finding worlds that are weirder than anything in our own solar system. We're just getting into a golden age of planetary discovery, and that means we shouldn't get too persnickety about planet definitions. At least that's the way I see it. How about you?

More about planets:

• Looking for alien Earths? Here they come
• Pluto debate is about more than one little world
• Pluto finds its place
• Interactive: The new solar system
• Gallery: Ten intriguing extrasolar planets

Correction for 6 p.m. ET: In the heat of adding in material from the press briefing, I scrambled up the name of the researcher (Barbara McArthur) with the name of the observatory (McDonald). Sorry about that!

Update for 6:45 p.m. ET: The University of Washington's Rory Barnes also discussed separate theoretical work he's been doing on the question of habitable worlds beyond our solar system. He suggests that some seemingly habitable planets might not be all that conducive to life as we know it, due to their gravitational interaction with other planets.

For example, suppose you were on a not-yet-detected Earthlike world in the Upsilon Andromedae system. That alien Earth could be sent topsy-turvy during periodic encounters with a Jupiter-scale planet in an elliptical, tipped orbit. It might be pushed outside its habitable zone, icing over and putting life in the deep freeze. It might be pulled into a tighter orbit, turning a habitable climate into a volcanic hell. It could even be spun in unconventional ways, producing chaotic variations in the length of the planet's days and its seasons.

Barnes says it's hard to tell just how many so-called "tilt-a-worlds" exist, but they're at least theoretically possible. "It's fascinating to think about how evolution occurs on such a world," Barnes said in a UW news release.

Barnes' research, presented during the AAS meeting, follows up on a paper published last year in The Astrophysical Journal Letters. The work is funded by NASA's Virtual Planetary Laboratory, and was conducted along with Brian Jackson of NASA's Goddard Space Flight Center, Richard Greenberg of the University of Arizona and Sean Raymond of the Laboratoire d'Astrophysique de Bordeaux in France.

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Thierry Legault

Silhouettes of the shuttle Atlantis and the International Space Station pass over the sun's disk in a May 16 picture captured by astrophotographer Thierry Legault. Click on the image to see a larger view from Legault's website, Astrophoto.fr.

The space shuttle Atlantis' final mission is hitting new heights for fantastic pictures - in part because every flight brings improvements in NASA's capability to capture imagery, and in part because photographers are taking extra care to document the end of the shuttle era. For us earthbound spectators, it's the next best thing to being there.

For example, in the wake of the 2003 Columbia tragedy, the space agency mounted an array of cameras on the shuttle's solid-rocket boosters. Those cameras capture images from different perspectives during the ascent from the launch pad - and when the boosters fall back into the sea, the video is retrieved and checked for any signs of damage to the shuttle.

In addition to ensuring the shuttle's safety, the video makes for a great show. You can feel as if you're riding a rocket all the way up to space and then falling back to Earth. You can even see the shadow of the rocket plume stretching out from the launch pad as you ascend. Give it a look:

NASA TV

Click for video: The shuttle Atlantis leaves its solid-rocket boosters behind on May 14 to head for orbit and the International Space Station. Click on the image to watch a compilation of "rocket-cam" views.

As Atlantis caught up to the International Space Station, astrophotographer Thierry Legault snapped a picture of the two spaceships silhouetted against the sun's disk. Legault has earned recognition as one of the world's most dedicated amateur space shooters, and you'll find plenty of out-of-this-world shots at his website, Astrophoto.fr. Space.com has the full story behind the picture you see at the top of this item, which was taken from Madrid, Spain, less than an hour before Atlantis docked with the space station.

The picture below shows what the astronauts on the International Space Station were seeing at about the same time. In the foreground, Atlantis is in the midst of its pre-docking maneuvers. In the background, the coast of Spain sweeps around the Gulf of Cadiz.

Before every docking, the space shuttle does a 360-degree flip so that astronauts aboard the station can snap hundreds of high-resolution pictures of the spaceship's protective skin. Those pictures are downlinked so that engineers on the ground can once again check for damage. Click on the picture to watch a high-speed video that gives you the high points of the eight-minute maneuver in just 30 seconds: 

NASA

Click for video: The space shuttle Atlantis approaches the International Space Station on May 16 with its payload bay doors open. The Atlantic coast of Spain and the Gulf of Cadiz can be seen far below. Click on the image to watch a time-compressed video of the shuttle's pre-docking "backflip."

NASA has been putting out tons of great pictures during the docked phase of Atlantis' mission. Check out the NASA Human Spaceflight website and NASA's shuttle multimedia page as well as the picture gallery on display at Universe Today. The picture below is particularly poignant, because it may be one of the last good views of Atlantis hooked up to the space station: 

NASA

A camera on the International Space Station shows the shuttle Atlantis docked to the station's Destiny laboratory on May 17. Click on the picture for a larger version.

We can look forward to more great pictures from the mission over the weekend, when Atlantis is due to pull away from the space station and take some snapshots of the orbital outpost during the shuttle's traditional "fly-around." The landing will be another picturesque and bittersweet moment, because it could well be Atlantis' final touchdown before retirement.

But this isn't the end of the road for Atlantis. Not yet. The spaceship will be put through yet another round of processing so that it can stand by as a backup rescue vehicle for the last scheduled shuttle mission, due for launch no earlier than November. Even if Atlantis stays put then (which we all hope will be the case), there's a chance that NASA will get the go-ahead to use the orbiter for an extra space station supply mission in mid-2011.

To get an idea of what will happen to Atlantis after it lands, check out this must-see video on the Air & Space website. Photographers Scott Andrews, Stan Jirman and Philip Scott Andrews painstakingly documented the pre-launch processing routine for the shuttle Discovery in advance of its April mission to the space station. The time-lapse photography squeezes six weeks of NASA awesomeness into a four-minute video clip:

Jim Grossmann / NASA

Click for video: The shuttle Discovery is brought into the Vehicle Assembly Building on Feb. 22 in preparation for its STS-131 flight to the International Space Station in April. Click on the image to watch an Air & Space time-lapse video tracking Discovery's route from its previous landing to the STS-131 launch.

The mini-documentary, which was conceived with the help of STS-131 shuttle commander Alan Poindexter and created with the full cooperation of the space agency, serves as a fitting record showing how NASA gets the world's most complex flying machine ready for outer space.

What are your thoughts as the first "last shuttle mission" nears its close? Feel free to add your comments below.

Update for 11 p.m. ET May 21: We've also added a few new pictures to the collection of launch pictures submitted by msnbc.com users - including some golden oldies from the shuttle fleet's heyday.

Update for 1 p.m. ET May 22: One of the most active shutterbugs ever to live on the space station is Japanese astronaut Soichi Noguchi, who has shared more than 600 pictures on his Twitpic website. Some of the pictures show scenes inside the station, but the large majority of them are jaw-droppingly beautiful views of Earth.

Few pictures merit that "jaw-dropping" label more than the image below - a view of Atlantis docked to the space station, with Japan's laboratory module, a dark planet, the bright moon and the green glow of the aurora in the background. Astroengine blogger Ian O'Neill says "this should be the photograph of Atlantis' final mission."

Like Atlantis, Noguchi is nearing the end of his current stint in space. He's due to return to Earth aboard a Soyuz spaceship early next month. Here's hoping there'll always be such active (and generous) witnesses to the wonders of the cosmos:

Soichi Noguchi / JAXA via Twitpic

A photo by Japanese astronaut Soichi Noguchi shows the shuttle Atlantis docked to the International Space Station with an auroral glow in the background. Click on the picture to see a larger version on Noguchi's Twitpic site.

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An artificial butterfly takes wing in a video from the Institute of Physics.

Why a robo-butterfly? Some robotics experts build buglike or birdlike machines, also known as entomopters and ornithopters, to serve as tiny airborne spies. Japanese researchers had a different purpose in mind: Harvard's Hiroto Tanaka and the University of Tokyo's Isao Shimoyama wanted to figure out how actual swallowtail butterflies navigate through the air.

You see, because the swallowtails' forewings partly overlap their hind wings, they don't have as much aerodynamic control as other flying bugs. Tanaka and Shimoyama fiddled with a mechanical swallowtail to see whether they could reproducing the characteristic undulating flight of the butterfly.

"The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion," the researchers report this week in the journal Bioinspiration and Biomimetics. In the video above, you can watch their contraption float like a butterfly. But unlike military-issue entomopters, this one won't sting like a bee.

More about biomimetic flying (and hopping) machines:

• First flapping, two-winged aircraft takes flight
• Robotic craft mimics falling maple seeds
• Leaping robot could aid space exploration
• Tiny robots could hop across Mars
• One giant leap for micro-robots
• Spy plane maneuvers like a bird

• New Horizons: Visions of geysers on Pluto
• 'Nova' on PBS: 'Mystery of the Megavolcano'
• Science News: Space telescope spots extrasolar ice ring
• Space Transport News: SpaceShipTwo sprouts extra fin
• New Scientist: Levitating glass bead proves Einstein wrong
• Modern Survival Blog: Uh-oh! Another Iceland volcano just rumbled

A time-lapse YouTube video compresses the six-hour process of inflating
E-Green Technology's 235-foot-long Bullet 580 airship into two minutes.

The biggest airship in existence passed its first full-up inflation test this week inside Garrett Coliseum in Montgomery, Ala., opening the way for its maiden flight later this year. You can watch E-Green Technologies blow up the 235-foot-long, 65-foot-diameter Bullet 580 in this time-lapse video.

E-Green says the blimp ... er, airship ... can carry payloads of up to 2,000 pounds to altitudes of 20,000 feet, and is capable of going 80 mph. The first flight is destined to carry an experimental payload developed by NASA and Old Dominion University to measure moisture content in soil. Eventually, such airships could be used as "stratellites" for communications, weather monitoring, surveys and surveillance. They could even be used as floating weapons platforms, E-Green says.

The largest airship that ever flew was the 804-foot-long Hindenburg, a hydrogen-filled German passenger craft that famously went down in flames in 1937, killing 36 people. Oh, the humanity! The Bullet 580 will be much, much safer because it's filled with nonflammable helium and has a Kevlar coating.

E-Green spokesman Ian Murphy told me that some airships in operation today, such as the Zeppelin NT, are longer - but measured by volume, the $8 million Bullet is the biggest. And even bigger airships are on the way, from E-Green as well as other companies. "The airship industry is at the beginning of a boom," Murphy said.

For more on the airship venture, check out this video backgrounder from E-Green, this Discovery News report and this week's update from Discovery's Irene Klotz.

Daniel Beltrá / Greenpeace via EPA

An aerial view shows ships surrounded by the Gulf of Mexico oil slick on May 18.

The Gulf of Mexico oil spill is entering a new phase, one month after the explosion that touched off the disaster. It's finally sinking in among environmental experts, policymakers and the general public that this spill is unlike any other. The impact will be felt hundreds of miles away from the deep-sea leak, for years after it's been stopped.

"We have to be ready for the long haul, to see this through. ... Maybe nationally, people might draw their attention away from this incident," Coast Guard Rear Adm. Mary Landry, one of the leaders of the oil-spill response team, told reporters. "I want to assure you that there will still be people working on this response."

But a month of round-the-clock efforts to block the leak and fight the spill is beginning to take its toll. "The people actually start to get tired," said Doug Suttles, chief operating officer of BP, the oil company responsible for cleaning up the spill. "We have to make sure they get the appropriate rest and rotate out."

The spill's environmental impact has widened significantly just in the past couple of days:

• Federal officials doubled the area of the Gulf of Mexico where fishing is banned due to the spill. The ban takes a 46,000-square-mile chunk out of some of America's most productive coastal fishing grounds - and some experts say Gulf seafood may have to be tested for oil pollution for decades to come.
• The National Oceanic and Atmospheric Administration says a portion of the slick has reached the Gulf's Loop Current, entering an ocean circulation system that could carry oil to the Florida coastline and around to the Atlantic Seaboard.
• Much of the oil has been broken up by dispersants, dropped onto the ocean from above or injected into the stream beneath the surface. But on Wednesday, Louisiana Gov. Bobby Jindal said heavy oil made its first significant landfall in the state's coastal marshlands. "The day that we have all been fearing is upon us today," he told reporters. 

The situation started out as a localized tragedy on April 20, when a natural-gas explosion sank the Deepwater Horizon oil rig 50 miles off the Louisiana coast, killing 11 workers. The rig's fail-safe systems should have stopped any oil from leaking, but those systems didn't work. Now BP is trying a variety of strategies to contain the spill, as well as to reduce and eventually stop the leak.  

In the meantime, hundreds of thousands of gallons of oil are being added to the mess in the Gulf every day - and the impatience is mounting, particularly in Louisiana's coastal communities.

"We Americans are impatient as a rule, even us Cajuns," said oil-spill expert Ralph Portier, a Louisiana State University professor who hails from Bayou Petit Caillou. "We have a joie de vivre, but we also have a mind-set to go out and fix the damn thing."

If the spill drags on too much longer, coastal residents might start taking the matter into their own hands. Portier said there's talk of building mud or sand barriers to block incoming oil. "They want to physically put something down to keep it out of the marsh," he said. "Once you oil that habitat in a major way, you have a legacy of a spill that's going to be there for some time."

What's been learned?
For Portier and other scientists, the biggest lesson from the past 30 days was finding out how much they didn't know about the challenges of deep-sea drilling. "There are a lot of things we don't know, but at least now we know that we don't know," he said.

Ed Overton, a chemist at LSU who specializes in environmental monitoring, said the oil-spill response plans were "woefully inadequate" for dealing with an major oil leak a mile beneath the sea surface. "The first thing we learned is that we weren't prepared for a deep-water spill," he told me.

Experts disagree over how much oil is leaking, and they continue to debate the intensive use of dispersants. How toxic are those chemicals? Is breaking up the oil worth the risk? Overton said that debate "will probably last as long as you and I are talking about it."

Rick Steiner, a retired University of Alaska marine biologist who has been helping out Greenpeace, said "a lot of the damage that has occurred over this past month has been offshore and in the water column, and that's not the kind of place we're used to seeing." The spill is just now entering the phase where the effects are becoming visible onshore, he said.

"There's a lot about this spill that nobody has seen before," he said.

What's in store?
The developments of the past few days point to what's ahead: More of the leaked oil will start circulating in the Loop Current. In fact, Steiner said globs of subsurface oil "could already be in the Loop Current and traveling down the west coast of Florida."

Overton doesn't think having the oil spread around is necessarily a bad thing. "Concentrated oil is bad," he said. "Dispersed oil is not nearly as bad. Mother Nature can handle it."

Much is being made over tar balls that could eventually wash up on shores hundreds of miles from the site of the leak. Maybe too much, Overton said. "Tar balls are ultimately not dangerous," he said. "They might be unsightly, but you're not dealing with anything that's dangerous. A tar ball on Key West is not that big a deal. Now, I'm not on Key West, so it's easy for me to say that."

For Overton, the bigger concern is the oil creeping toward Louisiana's coastal marshlands. "It's not only damage to the critters that are there, it's loss of coastal habitat," he said. "It's a double-whammy along the coast of Louisiana."

The onset of hurricane season could bring on another kind of double-whammy. The spill response team says that the current stretch of calm weather has helped workers corral the oil with 1.8 million feet of containment booms. There haven't yet been any storms to drive the oil slick quickly toward the coast. The oil that is drifting toward the coast has had more of a chance to evaporate or degrade.

"That's the silver lining, if you will, around this tragedy," Portier said.

During the current stage of the crisis, then, bad weather is bad for the cleanup. But eventually, the right kind of bad weather could help beat down the slick, Overton suggested. "I wouldn't wish hurricanes on anybody, but a nice little tropical storm wouldn't be all that bad," he said.

What is to be done?
As the weeks roll on, the "human element" will become an increasingly important factor in sizing up the impact of the oil spill, Portier said. The fishing industry and the oil industry are important pillars of the economy and social fabric of coastal Louisiana. What will a long-running environmental crisis do to the region and its residents?

"The benchmark is probably Katrina," Portier told me. "The folks in the coastal zone, where I'm from, are intuitively, realistically and pragmatically looking at this as a slow-moving hurricane."

At least when a hurricane hits, you can be fairly certain that it will soon move on. Unfortunately, that's not the case here. "The fact that we have a never-ending spill, it's just a nightmare," Portier said. "If we had a finite spill, people would say, 'Oh well, act of God, take care of it, fix it up, move on.' What's unsettling about this is that we can't see the finish line."

The finish line could come into sight next week, when BP tries to plug up the top of the leaking oil well with heavy mud. Or it could take two or three months, when workers finish drilling a relief well and can plug up the line from below.

In the meantime, regulators and oil companies are talking about heading off future crises by rewriting the rules for offshore drilling.

Steiner said BP should have had all its well-stopping strategies ready to go "long before they had the blowout," rather than working them out only after the explosion. He noted, for example, that the Canadian government requires offshore oil ventures to drill a relief well during the same season that the exploratory well is drilled.

However, Steiner said merely tightening regulations for oil drilling won't be enough. In his view, the past month's troubles have provided "a clear view into the cost of oil." He said the White House and Congress shouldn't expand offshore drilling, but instead should lay the groundwork for an energy economy based on higher efficiency and renewable energy sources.

"If the only thing we fix in the wake of this Deepwater Horizon disaster is safety and regulatory oversight of offshore drilling, we've missed the transcendent lesson," he told me. "We've got to make the leap this time."

What do you think will happen in the next month, or the next year? What do you think should happen? Feel free to weigh in with your comments below.

Past postings on the oil spill:

• See the spill from space
• How risky is offshore oil?
• How to stop the oil leak
• How bad can the spill get?
• Complete coverage of the spill

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