Monthly Archives: July 2010

Cassini’s slant on the rings | Bad Astronomy

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Check out this latest image from Cassini at Saturn!

cassini_diagonalrings

[Click to embiggen.]

Oh, wow! This was taken when the spacecraft was almost in the plane of the rings, which are incredibly thin. You can see several different rings, including the broad A ring in the middle and the thin F ring on the outside. There are also two moons: Janus (the larger one, above) and Prometheus (smaller, below). Janus is about 180 km (110 miles) across, which isn’t terribly big, but Prometheus is even smaller: 120 km (75 miles).

cassini_epimetheus_pandoraThis picture made me smile not only because it is carved out of raw coolness, but also because it’s the complement of an earlier image from Cassini (to the right). The earlier shot is of the moon Epimetheus, which shares an orbit with Janus, and Pandora, which shares an orbit with Prometheus! So the two images go together like a pair of gloves, each showing one of a pair of orbit-sharing moons.

Also, in the big image, take a look at the thin F ring: follow it from the far side to the near side. Just as you pass the bottom left and start moving to the upper right, do you see two spots where it appears thicker, like it’s lumpy? Well, it is lumpy! Pandora and Prometheus are the ring’s shepherd moons, using their gravity to keep the ring particles tightly in place. But when they pass any given point in the rings, their gravity leaves a wake behind, almost like a boat’s wake. That deforms the ring a bit, and you can see that in this image as a thickening in the ring. The animation I’ve inserted here actually shows that as it happens.

Amazing, what can be seen in a single image from Saturn. Especially if you have other images to back it up.

I like this new image a lot. Hmmm, have I found my new desktop picture? Why yes, yes I have.

Tip o’ the CICLOPS to Carolyn Porco.

Related posts:

- A little weekend Saturn awesomeness
- Cassini eavesdrops on orbit-swapping moons
- Dr. Tongue’s 3D House of Prometheus
- The bringer of fire hiding in the rings


Brilliant & Reclusive Russian Mathematician Doesn’t Need Your Prize Money | 80beats

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perelmanGrigori Perelman isn’t much for prizes. This week Perelman, one of the world best and strangest mathematicians, proved it again by turning down a $1 million dollar prize from the Clay Mathematics Institute Millennium Prize for solving one of the most troubling math problems of the last century.

The Poincaré conjecture, named after prominent French mathematician Henri Poincaré, involves a complex problem in the field of topology — an important area of math that studies the enduring properties of objects that are stretched or otherwise deformed, but not torn or otherwise reconstituted. Scores of prominent mathematicians tried to solve it over decades but failed, leading to its characterization as the Mount Everest of math [Washington Post].

In 2003 Perelman put forth his solution to the conjecture, but not in the traditional way of putting it through the peer review process. Instead, he simply emerged from the shadows and threw his work up on the Internet with in a rebellious, “ta-da,” and waited for the world to catch up.

After a brief barnstorming tour in the United States, during which he refused interviews, Dr. Perelman returned to Russia, leaving the world’s mathematicians to pick up the pieces and decide whether he had really done it. A worldwide race to retrace, explicate and check Dr. Perelman’s proof ensued. In the meantime, Dr. Perelman quit his post at the Steklov Mathematical Institute, moved in with his mother and ceased communicating with the outside world [The New York Times].

Therefore, confirming what Perelman had achieved took several years of work fraught with difficulty understanding his methods (and rivalry with mathematicians like Shing-Tung Yau), as documented in a great New Yorker piece on Perelman from 2006.

It was astonishingly brief for such an ambitious piece of work; logic sequences that could have been elaborated over many pages were often severely compressed. Moreover, the proof made no direct mention of the Poincaré and included many elegant results that were irrelevant to the central argument. But, four years later, at least two teams of experts had vetted the proof and had found no significant gaps or errors in it. A consensus was emerging in the math community: Perelman had solved the Poincaré. Even so, the proof’s complexity—and Perelman’s use of shorthand in making some of his most important claims—made it vulnerable to challenge. Few mathematicians had the expertise necessary to evaluate and defend it [New Yorker].

Perelman turned down the 2006 Fields Medal, and now has officially turned down the Clay prize as well. The reason, according to the reclusive Perelman, is that he built on the work of the American mathematician Richard Hamilton, who deserves as much credit as him. The Clay leaders tried to convince Perelman he should accept, since all great work is built on the shoulders of giants. But, true to form, the eccentric genius stays quiet and hidden away in Russia.

Related Content:
80beats: Can a Google Algorithm Predict Nobel Prize Winners?
80beats: How the Russian Spies Hid Secret Messages in Public, Online Pictures
DISCOVER Interview: The Math Behind the Physics Behind the Universe
DISCOVER: Top Math Stories of 2006, featuring Perelman’s achievement

Image: American Mathematical Society


Tibetans May Be the Fastest-Evolving Humans We’ve Ever Seen | 80beats

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Tibetan_ladyClearly, the people of Tibet must have evolved quickly to tolerate a life spent living at the top of the world. How quickly? A study out in this week’s Science, which compared Tibetans to Han Chinese to see the differences in their DNA, says that the two groups may have diverged no more than 3,000 years ago. If natural selection has changed Tibetans in such a short time, it would be the fastest known example of human evolution. But not everybody is buying this time line.

As DISCOVER noted when a similar study by another team came out in May, natives of the Tibetan plateau seem to survive the altitude because their bodies make less hemoglobin. It’s somewhat counter-intuitive:

In theory higher levels of haemoglobin would be beneficial, because this would improve oxygen transport. But high levels could make the blood thicker and less efficient at carrying oxygen, says Jay Storz of the University of Nebraska-Lincoln [New Scientist]. (Storz writes the accompanying commentary in Science.)

Looking at the differences in genes that regulate that, the team found vast differences between the Han and the Tibetans, with one version appearing in 87 percent of Tibetans studied but only 9 percent of Chinese. However, the assertion by the scientists at the Beijing Genome Institute—that their findings mean the two group broke apart just three millennia ago—has ruffled archaeologists who believe that the Tibetan plateau has been continuously occupied for much, much longer: more like 7,000 to 21,000 years.

For more about all of this, check out Razib Khan’s post at Gene Expression.

Related Content:
Gene Expression: Very Recent Altitude Adaptation in Tibet
Gene Expression: Tibet & Tibetans, Not Coterminus
80beats: Found: The Genes That Help Tibetans Live at the Top of the World
DISCOVER: High-Altitude Determines Who Survives in Tibet

Image: Wikimedia Commons


Big bruiser stars form like their wimpy little siblings | Bad Astronomy

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Astronomers using the UK’s Infrared Telescope (UKIRT) have made an important discovery: massive stars form much like lower mass stars do.

That doesn’t seem surprising, does it? Ah, but it is. It turns out that massive stars are different than the hoi polloi like the Sun, and it’s a bit puzzling that they can form at all!

ukirt_massivestarform

As I’ve written many times before, stars form from clouds of gas and dust. A cloud can be huge, light years across, its massive gravity balanced by internal heat. But collisions between clouds or nearby exploding stars can disturb that equilibrium, compressing the cloud. Random eddies and whorls in the cloud can be accelerated, amplified by the collapse, giving the entire complex an overall rotation. Random collisions between pockets of matter inside the cloud slowly rob them of energy, causing them to move inward, falling toward the cloud’s equator. What was once a giant amorphous mass is now a relatively rapidly spinning disk of material.

The disk gets denser toward the center. As the material compresses there, it heats up. Eventually, if enough matter piles on, the temperature and pressure at the very center can be enough to fuse hydrogen into helium, and a star is born.

But there’s more to this story. Massive stars are far hotter than lower mass stars. As the material from the disk accretes onto the protostar, the protostar gets hotter. If it gets too hot, it’ll blow away the disk, preventing the star from gaining any more mass. Yet we see more massive stars. How do they form then? Is it the merging of two lower mass stars, or some other process? Any scenario like that would mean that massive stars form differently than lower mass stars, and we should be able to see that.

Enter the UKIRT observations. It’s really hard to see what’s going on deep in the heart of a star-forming cloud, because they’re opaque to optical light. Infrared light, however, gets out. Astronomers used UKIRT to look at 50 high-mass young stellar objects, as they’re called, to see if they reveal themselves to be different than lower mass stars.

The result they found surprised them: these hefty stars form pretty much like lighter-weight stars.

The key to this was the presence of jets, beams of matter and energy blasting out from the poles of the stars. These jets are focused by a lot of forces, but critical to them is the presence of the disk of material from which the star forms. They saw these jets coming from massive young stars (like in the picture above; the red glow is from material in the jets) and they look pretty much like they do in their low mass star counterparts. Not only that, the jets seen in massive stars are well-defined and don’t appear to depend in any way on the amount of energy the star is producing; fiercely hot and bright stars make jets as easily and as nicely as relatively calmer stars.

A study last year indicated that instabilities in the cloud as it collapses help the massive stars form, but that was done in a computer by modeling the physics. These new observations show that this process may yet be correct, since there’s no need to make a massive star by colliding smaller ones, for example. It’s not proof, but it doesn’t contradict the earlier test either.

Still, what’s clear is that whatever process is going on in the heart of a star-forming cloud appears to work the same way for stars up to a mass of at least 30 times the Sun’s mass (the astronomers didn’t observe any stars more massive than that). This is good news! The puzzle of the formation of massive stars just had another puzzle piece fall into place.


More Responses on Scientists’ Understanding of the Public | The Intersection

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Well, this topic has really run away on its own at this point. I can no longer keep track of all the things that have been said. I find Chad Orzel's thread the best, because it really gets into a lot of the baffling reactions, many of which amount to saying, "this oped omits X" -- even though X is to be found in the longer paper, or in the American Academy's lengthy transcripts which I was asked to summarize. So I really feel that the people who are making this argument about omissions, without even mentioning the longer work, are being unfair. An example would be Evil Monkey--here criticizing the Post piece without mentioning the longer paper, and yet nevertheless saying "I've already done more than Mooney. I've made a couple concrete suggestions for how the problem needs to be addressed"; here glossing over that omission by saying the prior post "was directed at the Op-ed, which was pedantic and useless, if not counterproductive." Look: Everybody knows that one has to pare a topic down in order to write shorter articles, especially for mass media outlets rather than specialized ones. I've really seen nothing raised as an alleged omission in my Washington ...


Progress 38P Docks With ISS

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NASA ISS On-Orbit Status 4 July 2010

"At 12:17pm EDT, Progress M-06M(38P) docked successfully to the SM (Service Module) aft port under KURS autopilot control, followed by a final DPO post-contact thrusting burn, docking probe retraction and hook closure ("sborka") after motion damp-out while the ISS was in free drift for ~20 min (12:17pm-12:37pm). At "hooks closed" signal, the SM returned to active attitude control, maneuvering the ISS to LVLH TEA (local vertical/local horizontal Torque Equilibrium Attitude) at ~12:37pm."

New Horizons Adjusts Course

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Course Correction Keeps New Horizons on Path to Pluto

"A short but important course-correction maneuver kept New Horizons on track to reach the "aim point" for its 2015 encounter with Pluto. The deep-space equivalent of a tap on the gas pedal, the June 30 thruster-firing lasted 35.6 seconds and sped New Horizons up by just about one mile per hour. But it was enough to make sure that New Horizons will make its planned closest approach 7,767 miles (12,500 kilometers) above Pluto at 7:49 a.m. EDT on July 14, 2015."

Charlie Bolden: Stealth Middle East Diplomat?

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"Bolden: I am here in the region - its sort of the first anniversary of President Barack Obama's visit to Cairo - and his speech there when he gave what has now become known as Obama's "Cairo Initiative" where he announced that he wanted this to become a new beginning of the relationship between the United States and the Muslim world. When I became the NASA Administrator - before I became the NASA Administrator - he charged me with three things: One was that he wanted me to re-inspire children to want to get into science and math, that he wanted me to expand our international relationships, and third, and perhaps foremost, he wanted me to find a way to reach out to the Muslim world and engage much more with predominantly Muslim nations to help them feel good about their historic contribution to science, math, and engineering."

Question: Are you in some sort of diplomatic role .. to win hearts and minds?

Bolden: NO NO, not at all. Its not a diplomatic anything. What it is - is that it is trying to expand our outreach so that we get more people who can contribute to the things that we do - the international Space Station is as great as it is because we have a conglomerate of about 15 plus nations who have contributed something to that partnership that has made it what it is today ..."

Editor's note: I have shut off comments on this post. I am tired of reading hate language that people have been trying to post. This will not be tolerated on NASA Watch.

On Orbit Photo Caption Needed

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From Astro_Wheels: "Best Caption Contest - I am floating through the transfer hatch to my position in the Soyuz capsule, all suited and ready to take 'Olympus' for a spin around the block for re-docking. Would love to hear your ideas for a caption, maybe "Did you guys see the keys"?..."

Submit your suggestion here

Why Aren’t We Hearing More About JSC’s Project-M?

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"This video is of NASA Project M Lander free flight test at Armadillo Aerospace outside of Dallas. The lander launched on June 23rd 2010. This is the prototype of the lander that will launch a version of Robonaut on future exploratory missions."

Keith's note: This is an interesting project, to be certain - and Armadillo's involvement is innovative and is to be commended. But I am wondering how or why this project is being funded (and is building hardware) at a time when other ESMD lunar surface activities are grinding to halt (Altair etc.). Given that NASA has yet to decide what places it is (or is not) going to - with the Moon no longer being the core focus, it is a bit curious that JSC is planning to land something on the Moon in 2013 and refers to this hardware as something that "will launch" Robonaut. Not "might launch" or "could launch" or "if approved ..."

Also, it is a little weird that it is rather difficult to find anything detailed on this project at NASA.gov unless you happen to look at the Robonaut page at NASA JSC which has a link to a document titled "Landing a Humanoid Robot on the Moon in a 1000 Days "ProjectM". Curiously, this white paper is not even hosted at NASA.gov but rather is posted here at Scribd.com. You can also download it as a PDF here at SpaceRef.

It is also a little unusual that the NASAProjectM YouTube page is not listed as a channel on NASA's Official YouTube page. This is cool stuff - and you would think that the NASA.gov home page would be featuring it and that press releases would be issued each time that a successful test launch is completed.

New Launch Dates for STS-133 and STS-134

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NASA Updates Shuttle Target Launch Dates For Final Two Flights

"NASA is targeting approximately 4:33 p.m. EDT on Nov. 1 for the launch of space shuttle Discovery's STS-133 mission and 4:19 p.m. EST on Feb. 26, 2011, for the liftoff of shuttle Endeavour's STS-134 flight from the Kennedy Space Center in Florida. The target dates were adjusted because critical payload hardware for STS-133 will not be ready in time to support the previously planned Sept. 16 launch. With STS-133 moving to November, STS-134 cannot fly as planned, so the next available launch window is in February 2011."

Hutchison Pleased with Short-Term Shuttle Extension to 2011 - Calls Move "An Important First Step"

"Senator Kay Bailey Hutchison (R-Texas), Ranking Member on the Senate Commerce, Science, and Transportation Committee, today said she was pleased to see NASA delay the launch of the space shuttle Discovery to November 1, 2010, and push back the scheduled launch of space shuttle Endeavour to February 26, 2011. Senator Hutchison has consistently stated that the President's NASA proposal should include a short-term stretch out of the shuttle program's remaining flights in order to protect the nation's $100 billion investment in the International Space Station."

Kosmas Statement on the Extension of Shuttle Program into 2011

"Today, following NASA's decision to extend the Space Shuttle program until at least February 2011, Congresswoman Suzanne Kosmas (FL-24) issued the following statement: "Today's news that the Shuttle program has been officially extended until at least February of next year is a welcome development that will help preserve jobs and ease the transition for the Space Coast. The extension shows the importance of our successful efforts to eliminate the hard deadline for Shuttle retirement, which would have ended the Shuttle program in September of this year."

More Water Ice Found On The Moon

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Ice Rich Crater At The Moon's North Pole

"NASA Radar returns first high-resolution view of an unusual crater near Moon's north pole Mini-RF, a synthetic aperture radar on board NASA's Lunar Reconnaissance Orbiter, recently imaged a potentially ice-rich crater near the north pole of the Moon. Located at 84°N, 157°W, this permanently shadowed crater, about 5 miles (8 kilometers) in diameter, lies on the floor of the larger, more degraded crater Rozhdestvensky (110 miles, or 177 kilometers in diameter). With no sunlight to warm the crater floor and walls, ice brought to the Moon by comets or formed through interactions with the solar wind could potentially collect here."

ZeroG Responds to OIG Report

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Zero Gravity Corporation's statement regarding the Office of Inspector General's June 18, 2010 Audit Report of NASA's Microgravity Flight Services

"It is important to note that the report highlights that the cost-effectiveness of maintaining the operations-ready status of the C-9 and currency of its crew has never been assessed. Since the primary threat to ZERO-G's service continuity to NASA is its own insufficient demand, NASA may be a contributor to this risk and should assess the benefit of continuing to invest in the C-9 versus restructuring the current contract with ZERO-G. To date, ZERO-G has invested over $1.5 million to improve its baseline commercial capability to meet NASA's requirements. Total net revenue from the past two years has not allowed ZERO-G to recoup its initial investment."

NASA OIG is Not Pleased With ZeroG, earlier post

Directly Imaged Extrasolar Planet Confirmed

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First Directly Imaged Planet Confirmed Around Sun-like Star, Gemini Observatory

"A planet only about eight times the mass of Jupiter has been confirmed orbiting a Sun-like star at over 300 times farther from the star than the Earth is from our Sun. The newly confirmed planet is the least massive planet known to orbit at such a great distance from its host star. The discovery utilized high-resolution adaptive optics technology at the Gemini Observatory to take direct images and spectra of the planet."

Get Ready For The Continuing Resolution

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Spending Panel: Unclear Direction of Manned NASA Flights Adds to Uncertainty, Science

"So far, there doesn't appear to be any sign of compromise between the White House and opponents of the Administration's plan in Congress, who believe that canceling Constellation and investing in the development of commercial space flight to enable future space missions is a bad idea. As it is, it's unlikely that Congress will complete the budget-approval process--for NASA and most other agencies--before the congressional elections in November, which means that the budgets for most agencies will likely be determined by a continuing resolution."

House Appropriators Look to Authorizers for NASA Direction, Space News

"In the absence of authorization legislation, "this subcommittee has no business in appropriating even more funding for uncertain program outcomes," Mollohan said. "Accordingly, this bill makes the funding for human space exploration available only after the enactment of such authorization legislation."

Statement of Chairman Alan Mollohan Commerce, Justice, Science, and Related Agencies Appropriations Subcommittee June 29, 2010

"For NASA, the bill provides a total of $19 billion, an increase of $276 million over last year's level, including significant and long needed new investments in science and education. For Human Space Exploration, the bill provides $4.2 billion, as requested and $498 million above 2010, but takes no position on the President's proposed new direction for the program."

More Space Policy Reaction

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Obama space policy: Share the sandbox, Nature

"The most striking emphasis to me is something that is not at all new: a continued push to get the government out of the rocket business. Commercial space has been a clear focus of the new NASA ever since the presidential budget was released in February. But what's not clear is if it will end up happening, given Congressional intransigence."

White House Space Policy: Good News For Greens, Time

"NASA junkies continue to howl at the Obama administration's plans for human space exploration, and with good reason: there's just no there there."

Obama reverses Bush's policy on space, NY Times

"The Obama administration Monday unveiled a space policy that renounces the unilateral stance of the Bush administration and instead emphasizes international cooperation, including the possibility of an arms-control treaty that would limit the development of space weapons."

Obama Backs Away from Intergalactic Domination, Wired

"Space: to President Obama, it's an opportunity for nations to join gloved hands and perform a glorious multinational spacewalk, all for the good of science. But he's not ready to rule it out as a potential battlefield, either." W.H. releases National Space Policy, Politico

"NASA was not part of the press conference. Pavel said the space agency was just one of "a couple of dozen departments around the table," including the State Department, the Joint Chiefs of Staff and the Department of Energy, meeting to develop a policy that "reflected the president's priorities."

Commercial Spaceflight Federation Welcomes Newly Released National Space Policy

"Bretton Alexander, President of the Commercial Spaceflight Federation, stated, "The National Space Policy reinforces the President's new plan for NASA, particularly the use of commercial providers for transport of crew and cargo to the International Space Station. The National Space Policy recognizes the benefits of a robust commercial space industry and lays down a series of clear policies to enable further growth of this sector."

Helium Balloon: Newsletter Challenge (07/06/10)

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This month's Challenge Question:

You're in your car at a stoplight, with a helium-filled balloon pressed up against the center of the ceiling. When the light turns and you accelerate, what does the balloon do and why?

The Answer will be posted right here on CR4 on August 3rd.

Designing the Car of the Future

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Having survived a devastating recession, the auto industry is now racing to pinpoint what consumers want in tomorrow's cars, studying such factors as technical advances, changing behavior, and cultural trends. Should the auto be a mobile office, an entertainment center, or a flexible cargo platform