In 1986, in a flyby shooting, the Voyager 2 space probe took some of our first photos of Uranus. The planet looked blue-green and featureless, a planetary pokerface. In the decades since, we’ve learned that Uranus does have weather, visible as variations in color on the surface, and new photos from by the Keck II telescope in Hawaii (above) reveal the ice giant’s meteorology in more detail than ever before. The scalloped pattern near the equator is a ring of clouds; the busy, blue-flecked cap at the right end—the planet’s North Pole—are storms.
For sunny weather, try another planet: this one gets sunlight hundreds times weaker than we do on Earth, and the temperature of its upper atmosphere drops as low as -371 F, making it the coldest planet in the solar system.
Image via Lawrence Sromovsky, Pat Fry, Heidi Hammel, Imke de Pater/University of Wisconsin
What’s the News: While the Kepler spacecraft is busy finding solar system-loads of new planets, other astronomers are expanding our idea where planets could potentially be found. One astronomer wants to look for habitable planets around white dwarfs, arguing that any water-bearing exoplanets orbiting these tiny, dim stars would be much easier to find than those around main-sequence stars like our Sun. Another team dispenses with stars altogether and speculates that dark matter explosions inside a planet could hypothetically make it warm enough to be habitable, even without a star. “This is a fascinating, and highly original idea,” MIT exoplanet expert Sara Seager told Wired, referring to the dark matter hypothesis. “Original ideas are becoming more and more rare in exoplanet theory.”
How the Heck:
What’s the Context:
Not So Fast:
References: Eric Agol. “TRANSIT SURVEYS FOR EARTHS IN THE HABITABLE ZONES OF WHITE DWARFS.” doi: 10.1088/2041-8205/731/2/L31
Dan Hooper and Jason H. Steffen. “Dark Matter And The Habitability of Planets.” arXiv:1103.5086v1
Image: NASA/European Space Agency
Sometimes, distractions can be useful in themselves. That’s the message this week from the Planck space telescope, which has a mighty big mission: to take baby pictures of the universe. While it hasn’t yet accomplished that task, the preliminary disturbances that Planck scientists are now dealing with are yielding cosmic insights of their own.
Orbiting the Sun roughly 1.5 million kilometres from Earth, the Planck space-based telescope is scanning the sky for ultra-cold objects. Its instruments are chilled to just a tenth of a degree above absolute zero and are designed to pick up the faint microwave afterglow from the Big Bang, which scientists hope can tell them about the earliest moments of the Universe. [Nature News]
Planck was launched in spring of 2009 by the European Space Agency, and it’s still gathering data to complete its chart of this cosmic microwave background (CMB); researchers hope the map will shed light on the young universe’s brief “inflationary” period when it expanded extremely rapidly. At the moment, however, Planck is busy detecting other sources of microwaves so that it can subtract this “foreground” radiation from its map of the background.
So what are some of these sources?
The Kepler space telescope, launched nearly two years ago, has already proven its worth as an exoplanet hunter many times over. But the discoveries keep on coming. NASA just announced that Kepler has found its first rocky planet–and that the rocky world is only 1.4 times the size of Earth, making it the smallest exoplanet ever found.
Phil Plait explains that this nearly Earth-sized isn’t actually Earth-like and habitable:
[I]t orbits extremely close in to its star, circling over the star’s surface at a distance of roughly 3 million kilometers (1.8 million miles) — amazingly, it takes less than an Earth day to make one circuit. But being that close to a star comes at a price: the surface temperature of the planet must be several thousand degrees!
The planet, Kepler-10b, may not be habitable to life as we know it, but Plait is still plenty excited. Get the rest of the story on how the planet was found and what its discovery means over at Bad Astronomy.
80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
80beats: How Excited Should We Be About the New “Goldilocks” Exoplanet?
80beats: Astronomers Find a Bevy of Exoplanets; Won’t Discuss Most Interesting Ones
80beats: After a Flawless Launch, Kepler Telescope Gets Ready for Planet Hunting
DISCOVER: How Long Until We Find a Second Earth?
On her first true flight as an observatory, NASA’s plane-based infrared telescope (the Stratospheric Observatory for Infrared Astronomy, aka SOFIA) took a close look at Orion and other star clusters overnight on November 30th.
“The early science flight program serves to validate SOFIA‘s capabilities and demonstrate the observatory’s ability to make observations not possible from Earth-based telescopes,” said Bob Meyer, NASA’s SOFIA program manager. “It also marks SOFIA‘s transition from flying testbed to flying observatory, and it gives the international astronomical research community a new, highly versatile platform for studying the universe.” [press release]
SOFIA is a highly modified Boeing 747SP jetliner that now includes a 100-inch German telescope (bigger than the Hubble’s!). These early observations were made with a general-use mid-infrared camera called FORCAST designed by a group at Cornell University.
Since SOFIA cruises at altitudes between 39,000 and 45,000 feet above sea level, it’s above 99 percent of the atmosphere’s water vapor (which normally blocks infrared light from reaching earth). The camera captures images using these infrared rays, producing detailed pictures that couldn’t be taken from earth.
Hubble’s successor will be late, and over-budget. So concluded a NASA panel this week that investigate the James Webb Space Telescope, NASA’s next big thing, intended to survey the skies in infrared light with its 18-segment mirror. The word all along has been that James Webb would launch in 2014 at a cost of $5 billion, but the independent review (pdf) concluded that the earliest possible launch would be September 2015, and at a cost of more like $6.5 billion.
The report raised fear that other projects would be hurt. “This is NASA’s Hurricane Katrina,” said Alan P. Boss, who leads the subcommittee that advises NASA’s astrophysics program. The telescope, he said, “will leave nothing but devastation in the astrophysics division budget.” [The New York Times]
John R. Casani, who managed missions like Cassini and Voyager that are the picture of NASA success, led the panel. The technical side of the Webb telescope isn’t the problem, the report found–the management side is. The report faulted the management team for failing to make realistic estimates of the project’s costs and timetable, and further criticized NASA headquarters for not calling the managers on their impractical assessments.
Zoom, zoom: Today two asteroids make close flybys of the Earth, passing inside the orbit of the moon. We’re in no danger, NASA says, but these close passes are a reminder that the United States and the world need to figure out how we’re going to catch an asteroid that could be on a collision course with our planet.
The larger asteroid, called 2010 RX30, passed by this morning. The smaller, 2010 RF12, is due for a pass at 5:12 p.m. Eastern time today. RF12, which is estimated to be between 20 and 46 feet in diameter, will come within about 50,000 miles of the Earth.
This is higher than communications satellites in geosynchronous orbit 22,369 miles (36,000 km) above Earth. On average, the moon is about roughly 238,600 miles (384,000 km) from Earth, so 2010 RF12 will pass by at nearly 0.2 of that lunar distance. [MSNBC]
The one ring is back, and it’s beautiful.
What you see here is the aftermath of stellar death, rediscovered after NASA temporarily lost the ability to watch it play out. Astronomers tracked supernova 1987A after its discovery that year, picking up insights into what happens after a huge star expends itself. But in 2004, the Hubble Space Telescope‘s Space Telescope Imaging Spectrograph went kaput. The May 2009 space shuttle servicing mission repaired this eye in the sky, leading to a study in this week’s edition of the journal Science that reveals what’s behind this fluorescent view, and why that ring shines so brightly.
There is a lot of space to explore and a limited amount of money to spend. So every ten years the National Research Council’s “Decadal Survey“ recommends which astronomy and astrophysics projects should get first dibs. Last week, the committee released their recommendations for 2012 through 2021. The projects that got the thumbs-up from astronomers would tackle big tasks, like hunting for dark energy and seeking out new exoplanets.
Though funding agencies (like NASA, the National Science Foundation, and the Department of Energy), Congressional committees, and the scientific community often use the survey to select the observatories on which to focus attention and resources, some were skeptical about this report given the 2001 survey’s recommendations and results.
Although these reports have always been influential—policymakers like scientists to rank their needs—only two of the seven major projects that appeared on the wish list in the 2001 survey have been funded, leading astronomers to wonder if the exercise is as useful as they’d like it to be. Previous surveys have also been faulted for providing unrealistic cost estimates, as low as a fifth of what certain missions have ended up costing. As a result, there has been considerable pressure on the committee that authored [Friday's] report to prioritize projects more effectively and estimate costs better. [Science Insider]
Astronomers have confirmed it: Neptune has a stalker. They have spotted, for the first time, an asteroid follower that keeps a fairly constant distance behind the planet in its orbit around the sun. And there may be many more.
Asteroid 2008 LC18 can’t help itself. It’s caught in a balancing game between the gravitational tug of the sun and Neptune, and effects from its whirling course. The conflicting tugs cause the asteroid not to orbit Neptune or crash into it, but instead to follow the planet from a little distance behind (about 60 degrees on its path).
Neptune has five of the these pits–called Lagrangian points (see diagram below the fold)–but the spots ahead and behind the planet, researchers say, are best for asteroid-trapping, since the hold is particularly stable in these places. Researchers have previously spotted several asteroids in front of the planet (again by about 60 degrees), but this is the first time they’ve found one following it. The findings appeared online yesterday in Science.