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:
- Because white dwarfs are much smaller than our Sun, an Earth-sized planet that crossed in front of it would block more of its light, which should make these planets easier to spot. So astronomer Eric Agol suggests survey the 20,000 white dwarfs closest to Earth with relatively meager 1-meter ground telescopes.
- And because white dwarfs are so cool, a planet in a white dwarfs habitable zone would be very close, meaning its transit would happen very fast. Agol says we’d only need to watch a star for 32 hours to pick up on any transiting, habitable planets.
- One leading theory about dark matter is that it’s made of theoretical particles called WIMPS (weakly interacting massive particles). It’s thought that when WIMPs collide (if, of course, they exist), they would explode. Astronomers think that these WIMP explosions could possibly heat a planet enough to make it habitable.
- There are no immediate plans to test the dark matter hypothesis, which is quite theoretical, and any plan to find dark matter-fueled planets would need to look far from here: our part of the universe doesn’t have nearly enough dark matter to bring a planet to habitability.
What’s the Context:
Not So Fast:
- It’s not at all clear if white dwarfs have any planets, and if so, whether any of them could possibly support water or life as we know it. For one thing, planets in the habitable zone would be tidally locked with the star—permanent scalding daylight on one side; permanent frozen nighttime on the other.
- Taking 32 hours to find a planet orbiting a white dwarf may seem like a short time, but when you’re looking at tens of thousands of stars, it adds up. Agol told UW Today, “This could take a huge amount of time, even with [a network of telescopes].”
- And just like star-orbiting planets have their Goldilocks zones (not to hot or too cold), dark matter-containing planets would need the right amount of dark matter to be habitable. “It’s not something that’s likely to produce a lot of habitable planets,” Fermilab researcher Dan Hooper told Wired. “But in very special places and in very special models, it could do the trick.”
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?
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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.
Related Content:
80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
80beats: How Excited Should We Be About the New “Goldilocks” Exoplanet?
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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.
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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.
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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]
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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.
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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]
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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.
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Imagine an infantile version of our 4.6 billion-year-old sun. Now picture a “failed star,” a brown dwarf, about the size of Jupiter, tightly orbiting that 12 million year old stellar baby–at the distance Uranus orbits our sun. Astronomers have just found such a duo: a star about the mass of our sun with an unusually close brown dwarf companion.
Of the similarly situated brown dwarfs that astronomers have imaged, most keep their distance, orbiting at about 50 AU (or 50 times the average distance from the Earth to the sun). A team of astronomers believe the distance between this young sun, called PZ Tel A, and its dwarf companion, PZ Tel B, is less than half that, a mere 18 AU.
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Looking at a planetary nebula 6,500 light years away, scientists recognized an old friend: the buckyball. The large, soccer ball-shaped molecule–made from bonding 60 carbon atoms together–was first seen in a lab in 1985. In a paper published today in Science, scientists confirm the first known extraterrestrial existence of the rare carbon balls.
The buckyballs’ planetary nebula, called TC 1, surrounds a white dwarf star. Using NASA’s Spitzer Space Telescope, a team led by Jan Cami of the University of Western Ontario observed traces of the the 60-atom balls and their 70-atom cousins while looking at light coming from the white dwarf.
When light hits molecules and atoms, they will vibrate in specific, measurable ways–a field of science known as spectroscopy. One of Cami’s colleagues, who was studying Tc 1, found some unfamiliar fingerprints in the nebula’s infrared light. Cami recognized them as carbon’s 60-atom configuration and its favored 70-atom carbon partner. [Discovery News]
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Welcome to the Tarantula Nebula, home to heavy-weight stars. Using data from the Hubble Space Telescope and Very Large Telescope in Chile, scientists have found a star estimated at about 265 times the mass of the sun. That makes it by far the most massive star ever found, and challenges astronomers’ notions of just how big a star can get.
The Tarantula Nebula is 165,000 light years away in the the Large Magellenic Cloud galaxy. This star, called R136a1, is located in the R136 stellar cluster; with 10 million times the luminosity of the sun, it’s the brightest of a bevy of massive stars recently discovered. The finding, published earlier this month in the Monthly Notices of the Royal Astronomical Society, may require scientists to come up with a new stellar life cycle for the most massive stars. The life a star leads depends on its mass, and the previously estimated mass limit was thought to be around 150 times the sun’s mass.
Lead author Paul Crowther explains that the big guy falls into the stellar category of “blue supergiants,” which are still a mystery from start to finish: It’s not clear whether a star can be born this big, or whether it grows through mergers.
Supergiants also remain as much of a puzzle at the end of their lives. Although all will eventually go supernova, the type of explosion they will generate is unknown. They could form neutron stars or black holes or obliterate themselves. Whatever their fate is, he says, “We still can’t say.” [ScienceNOW]
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Our sun and a much bigger star that resides 10,000 light years away have something in common: the way they were born. Though scientists had previously wondered if stars 10 to 20 times the sun’s size required a different setup to grow, new observations show that both our sun and plus-sized stars can form from large hoops of dust called accretion disks.
Astronomers arrived at the findings, published online today in Nature, by weaving together observations from two observatories–the Very Large Telescope Interferometer of the European Southern Observatory in Chile and NASA’s orbital Spitzer Space Telescope. Researchers combined the observatories’ power to get a “virtual” telescope of much better resolution, the equivalent of one with a 280-foot mirror.
Lead researcher Stefan Kraus and his colleagues took a close peek at a 60,000-year-old stellar infant about 20 times our sun’s mass, called IRAS 13481-6124. The researchers were able to piece together temperature data to make a model of stellar birth that might resemble something from our 4.6 billion-year-old sun’s baby-book.
The team’s observations yielded a jackpot result: the discovery of a massive disk of dust and gas encircling the giant young star. “It’s the first time something like this has been observed,” Kraus said. “The disk very much resembles what we see around young stars that are much smaller, except everything is scaled up and more massive.” [Jet Propulsion Laboratory]
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It’s the 1840s. Rival astronomers in Britain and France separately toil away in their notebooks, fiercely guarding their calculations of just where a planet beyond Uranus might be hiding, hoping that they and their country will get the glory for finding it. When telescopes finally spot Neptune, the discovery leads to decades of debate over primacy, and scouring each man’s private data to determine who deserved the most credit.
Fast forward to the 21st century: Rivalries may have changed, but in the hunt for new planets—especially becoming the first to detect a new world like our own in a distant star system—defending one’s data to lay claim to discovery has not gone away.
This week the team behind NASA‘s planet-hunting space telescope, Kepler, announced that it has found more than 700 new candidates for exoplanets. Given that the current tally of known planets beyond our solar system stands near 460, that’s a huge announcement. But what’s drawn some attention is that more than half of the candidates won’t be released publicly at this time. These include smallest planet candidates—those closest to our own world in size—which won’t be officially announced until February 2011.
It’s no secret why:
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Show them the money: The winners of the Kavli Prizes have been announced, and the eight scientists will split a total of $3 million in prize money.
No, these aren’t the Nobels. The Kavlis are a relatively new award created to award scientists whose fields don’t get much recognition in Stockholm:
These are only the second ever recipients of Kavli Prizes, the biennial awards launched in 2008 by Fred Kavli. Recipients in the fields of astrophysics, neuroscience and nanoscience each receive a scroll, a gold medal and (perhaps most importantly) a share of the $1 million pot for each discipline [Nature].
1. Astrophysics
The prize recognized three men—Jerry Nelson, Roger Angel, and Raymond Wilson—not for finding new phenomena deep in the cosmos, but for engineering the telescopes to make those searches possible. Nelson and Angel are renowned for their prowess in casting the mirrors for the largest telescopes on Earth; Nelson’s work will go into the Thirty Meter Telescope, for which Mauna Kea in Hawaii was just chosen as the preferred location.
Dr. Wilson pioneered the use of a technology known as active optics, in which computer-controlled supports correct the shapes of telescope mirrors to cancel the distortions caused by gravity, wind and temperature, allowing astronomers to build mirrors that are thinner and lighter [The New York Times].
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