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Science magazine published two studies on Saturn today, which bring together past research with contemporary discoveries. One focuses on the rings, the other on Saturn's atmosphere. According to a release from AAAS:

Jeffrey Cuzzi and colleagues put a spotlight on the ring system surrounding Saturn, made mostly of water ice, and detail its many layers. Based on Cassini's near-infrared observations, the researchers suggest that the mysterious reddish coloration, which contaminates portions of the ring system, could be caused by small clusters of carbon rings or by negatively charged iron compounds. They also detail the dynamic, constantly changing nature of the rings' features, and note that the vigorous evolutionary processes altering their structure occur on extremely short timescales of years, months, or even days. Cuzzi and the researchers say that many of the processes affecting Saturn's rings can also be observed in protoplanetary disks-the precursors to new planets.

In addition:

Tamas Gombosi and Andrew Ingersoll reveal new and unique details about the planet's atmosphere, ionosphere, and magnetosphere. Using the tools on-board Cassini, these researchers analyzed the wind speeds and jet streams influencing Saturn's atmosphere and listened in on lightning storms rocking the face of the planet. They describe Saturn's magnetosphere, which forms around planets when solar winds interact with a planet's magnetic field, as a distinctive hybrid between Jupiter's and Earth's, unlike any other planets' in the solar system.

These images are true color, except the black-and-white one and the one with the bluish ring, which is enhanced. You can see the reddish tinge in some of the rings.

via Science Express

According to Space.com:

The new image is color-coded to depict the temperatures of different regions within the view. The whitish-pink areas are regions that are just a few tens of degrees above absolute zero, the theoretical coldest temperature possible in the universe (minus 459 degrees Fahrenheit or minus 273 degrees Celsius). Deeper, richer colors mark areas of minus 437 degrees Fahrenheit (minus 261 degrees Celsius). That's just 12 degrees Celsius warmer than absolute zero. While the warmer dust is concentrated along the plane of the Milky Way, the colder dust hovers above and below the galaxy's plane.

Nobody is entirely sure what causes the dust to take these precise shapes, though it's believed to be affected by the galaxy's rotation, as well as "particle jets" and radiation. Some of the clouds you see are made of dust, and others contain molecule storms. Some regions may eventually collapse and form star nurseries.

via Space.com

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In the dwarf galaxy Sculptor, this star is made out of the same material as the oldest stars in the Milky Way. The Harvard Center for Astrophysics found this beauty, and a press release explains:

"This star likely is almost as old as the universe itself," said astronomer Anna Frebel of the Harvard-Smithsonian Center for Astrophysics, lead author of the Nature paper reporting the finding.

Dwarf galaxies are small galaxies with just a few billion stars, compared to hundreds of billions in the Milky Way. In the "bottom-up model" of galaxy formation, large galaxies attained their size over billions of years by absorbing their smaller neighbors.

"If you watched a time-lapse movie of our galaxy, you would see a swarm of dwarf galaxies buzzing around it like bees around a beehive," explained Frebel. "Over time, those galaxies smashed together and mingled their stars to make one large galaxy - the Milky Way."

If dwarf galaxies are indeed the building blocks of larger galaxies, then the same kinds of stars should be found in both kinds of galaxies, especially in the case of old, "metal-poor" stars. To astronomers, "metals" are chemical elements heavier than hydrogen or helium. Because they are products of stellar evolution, metals were rare in the early Universe, and so old stars tend to be metal-poor.

Old stars in the Milky Way's halo can be extremely metal-poor, with metal abundances 100,000 times poorer than in the Sun, which is a typical younger, metal-rich star. Surveys over the past decade have failed to turn up any such extremely metal-poor stars in dwarf galaxies, however.

"The Milky Way seemed to have stars that were much more primitive than any of the stars in any of the dwarf galaxies," says co-author Josh Simon of the Observatories of the Carnegie Institution. "If dwarf galaxies were the original components of the Milky Way, then it's hard to understand why they wouldn't have similar stars."

The team suspected that the methods used to find metal-poor stars in dwarf galaxies were biased in a way that caused the surveys to miss the most metal-poor stars. Team member Evan Kirby, a Caltech astronomer, developed a method to estimate the metal abundances of large numbers of stars at a time, making it possible to efficiently search for the most metal-poor stars in dwarf galaxies.

"This was harder than finding a needle in a haystack. We needed to find a needle in a stack of needles," said Kirby. "We sorted through hundreds of candidates to find our target."

Among stars he found in the Sculptor dwarf galaxy was one faint, 18th-magnitude speck designated S1020549. Spectroscopic measurements of the star's light with Carnegie's Magellan-Clay telescope in Las Campanas, Chile, determined it to have a metal abundance 6,000 times lower than that of the Sun; this is five times lower than any other star found so far in a dwarf galaxy.

The researchers measured S1020549's total metal abundance from elements such as magnesium, calcium, titanium, and iron. The overall abundance pattern resembles those of old Milky Way stars, lending the first observational support to the idea that these galactic stars originally formed in dwarf galaxies.

You can download a supermassive version of the image over at the link. [Harvard Center for Astrophysics]

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Over at Bad Astronomy, Phil Plait explains:

ESO 306-17 sits about a billion light years from Earth. In this picture it looks like it's surrounded by other galaxies, but that's an illusion: all the other galaxies you see here are either much closer to us or much farther away . . . Michael West, who led the team that took these images, tells me the little elliptical at the bottom left of ESO 306-17 may be interacting with it. It's difficult to tell; but what is certain is that there are very few galaxies near the big one, far fewer than you'd expect.

Plait adds that this lonely galaxy shares certain properties with our own cannibalistic galaxy, the Milky Way. Both our galaxy and ESO 306-17 are surrounded by globular clusters left over from galaxies they consumed.

You can contemplate the universe in higher resolution with this gigantic version of the image.

This new "blue marble" image has gotten tons of attention since Gizmodo posted it a week or so ago, and now NASA has reposted high-res versions on the Goddard Space Flight Center's Flickr page.

Here's a second image:

And here's the animated version, showing our planet in motion, which NASA just posted:

[via Gizmodo]

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Leonardo DiCaprio narrates this documentary about the Hubble Space Telescope, which hits Imax theaters on March 19. Not only does it feature massive versions of some of your favorite Hubble space pics, it also includes some amazing Imax footage of last year's mission to repair the telescope. According to the Imax press release:

In May 2009, the crew of the Space Shuttle Atlantis launched a mission to make vital repairs and upgrades to the Hubble Space Telescope, the world's first space-based observatory, 350 miles above the Earth. On board was an IMAX 3D camera, operated by the shuttle astronauts. It captured stunning sequences of the five intricate spacewalks required to make those repairs, as well as close-up images of the effort to grasp the orbiting telescope with the shuttle's mechanical arm at 17,500 mph, and one unexpected problem that threatened to sabotage the entire mission.

"Hubble 3D" combines this breathtaking IMAX footage with images taken by the telescope during the nearly 20 years it has been our window into space. Through advanced computer visualization, Hubble's detailed data becomes a series of scientifically realistic flights that unfold on screen like a guided tour of the universe, through time and space.

Producer/director Toni Myers, who previously guided IMAX audiences into orbit with the acclaimed "Space Station 3D," says, "Astronauts we've worked with have described our footage as ‘the next best thing to being there.'"

The press release explains that the Hubble mission that the Imax cameras documented was fraught with challenges:

STS-125, the mission documented in "Hubble 3D," nearly didn't happen. Originally scheduled for 2006, it was cancelled due to safety concerns following the tragic crash of the Space Shuttle Columbia in February 2003. Despite support from the public and the scientific community, as well as within NASA, it simply didn't seem worth the risk-that is, until a contingency plan was proposed. NASA would prepare a second standby shuttle as a rescue
vehicle, to connect with Atlantis in space and collect its crew should there be a problem.

With this precaution in place, in May 2009 the Space Shuttle Atlantis flew up to meet Hubble. Its seven-member crew was led by Commander Scott D. Altman, marking his fourth venture into space. Alongside him was pilot Gregory C. Johnson, on his inaugural flight. Mission Specialist K. Megan McArthur, also on her inaugural flight, operated the shuttle's mechanical arm to grapple and secure the telescope inside the shuttle's payload bay
where it could be reached by the repair teams.

Two pairs of astronauts took turns on five separate EVAs (extra-vehicular activities), suspended in space outside the shuttle to work on the telescope. Mission Specialist John M. Grunsfeld, a veteran of five space flights, was paired with Mission Specialist Andrew J. Feustel, marking his first; and first-time spacewalker Mission Specialist Michael T. Good partnered with Mission Specialist Michael J. Massimino, who had flown twice before.

Throughout training and up to the moments before lift-off, Commander Altman reviewed the possibilities. He recalls, "I'd go through the mission in my mind. ‘What could go wrong? Are we ready to handle it?' Hubble has a tendency to throw you a curve. We had to imagine all the things that could happen, pre-flight, and come up with solutions."
"It's risky, but worth it," adds Johnson. "There were a tremendous number of people all around the world wanting Hubble back ‘alive' and it was our job to do that. It was a big mission. Every second was planned for success." The accomplishments of STS-125 would determine Hubble's immediate future: as either an increasingly valuable scientific tool or a mute and useless piece of orbiting detritus.

The mission objectives included upgrades to the telescope's Wide Field Camera and its Cosmic Origins Spectrograph, plus repairs to the Advanced Survey Camera and Imaging Spectrograph, making Hubble's vision deeper, clearer and more sensitive to color and light. They also made general repairs, replacing batteries and insulation, installing six new
gyroscopes and fixing an instrument that controls the flow of data, recently damaged due to an electrical problem.

Grunsfeld describes some of what audiences will see of the EVA work. "Generally one person rides on the end of the robotic arm which allows him to hold heavy objects, and the other person is the free floater, a little bit more mobile to do some of the other tasks, quickly, while the telescope rotates inside the shuttle's payload bay." Every stage of the spacewalking protocol was choreographed and practiced down to the last motion. In a situation where bumping into something could fatally damage an astronaut's protective suit and fumbling a tool could mean watching it drift away into eternity, any wrong move could result in a devastating loss. The crew rehearsed extensively in the two
years prior to launch, mostly underwater in the world's largest indoor pool at NASA's Neutral Buoyancy Lab (NBL) at the Johnson Space Center in Houston, Texas. Even so, Altman's prediction about Hubble throwing them a curve came true.

First, Grunsfeld and Feustel encountered a stuck bolt while trying to install the Wide Field camera on day five. It took some time and tense moments, but they finally managed to free it. The crew breathed a collective sigh of relief, but there was worse to come. On day seven, Massimino and Good were charged with replacing an obsolete piece of equipment with a highly advanced instrument designed to analyze, among other things, the atmosphere of distant planets. The hard part should have been the intricate work inside, but what proved problematic was a stripped bolt on the handle of the plate protecting it.

Massimino recounts, "We practiced so much for that task, over and over, obsessing over every detail. The easiest bolts to remove were the four on top. And in training, zip, zip, zip, they came right out. But there we were and this one was not coming out. It was a nightmare; the world was going by, the unthinkable happened and I couldn't go to the hardware store."

Though making light of it afterwards, Massimino's concern about the glitch and its potential repercussions is undeniable. "It's funny what goes through your mind," he admits. "I was thinking, ‘This is terrible. They're going to write textbooks about this and, instead of Hubble's discoveries, it's going to say: if it wasn't for Mike Massimino we'd know if there was life on other planets.'"

After hours of anxious work, much discussion among the crew and input from Mission Control, the best solution was the simplest, albeit the most counter-intuitive: break it off. Says Feustel, "Breaking the handle off wasn't part of the plan; it's just not normal. In fact, I gave Massimino specific instructions not to break anything," he jokes. The handle situation finally solved, the astronauts then wrapped up their repairs and celebrated the triumphant re-launch of the Hubble Space Telescope into orbit.

"There were many exhilarating moments caught on film, and certainly one of the best was when they released Hubble back into space," Myers cites. "This is an amazing crew. They succeeded on such a difficult mission, attempting things that had never been done in space before, beyond even what the planners thought they could achieve. To see them nail it, day after day, and to share a little in that sense of achievement, was very special."
Expressing the sentiments of her colleagues, McArthur says, "It's a tremendous feeling. It means so much to all of us, to be able to make a small contribution to the body of information we have about our universe."

The Bad Astronomer, Phil Plait, explains:

NGC 1427A looks like it's got a swept-back shape because it's being swept back. In between galaxies there is an ethereally-thin fog of gas, but there's enough there to have an effect on a passing galaxy. The boomerang shape of the galaxy is because that side is facing into the wind, so to speak, and being compressed. The pink curve in the image is due to rigorous star-formation going on there, where the gas clouds are collapsing from the pressure and birthing stars at a prodigious rate.

The rest of Phil's explanation is well worth checking out. [Discover Magazine]

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You can download these images in stunning high quality here. [NASA Mission Page]

Andromeda in a full-spectrum image from NASA's Wide-field Infrared Survey Explorer (WISE) camera.
An image of Andromeda using the shortest-wavelength camera on WISE, which detects infrared light of 3.4 microns. Says NASA, "A pronounced warp in the disk of the galaxy, the aftermath of a collision with another galaxy, can be clearly seen in the spiral arm to the upper left side of the galaxy."
The longest-spectrum image from WISE shows the hot gas of Andromeda's busiest star-making regions. Says NASA, "The hot dust, which is being heated by newborn stars, traces the spidery arms all the way to the center of the galaxy. Telltale signs of young stars can also be seen in the centers of Andromeda's smaller companion galaxies, M32 and M110."