The quest to find a second Earth–a potentially habitable planet that’s about the size of our home, but that lies in a distant solar system–has hit a snag. The Kepler space telescope was expected to be well on its way to detecting Earth-sized exoplanets by now, but an electronic glitch is slowing it down. The delays are caused by noisy amplifiers in the telescope’s electronics. The team is racing to fix the issue by changing the way data from the telescope is processed, but the delay could mean that ground-based observers now have the upper hand in the race to be the first to spot an Earth twin [Nature News].
Kepler, which was launched in March, uses the transit method to detect exoplanets; it’s watching a patch of 100,000 stars in hopes of detecting the brief dimming of a star’s light, which indicates that a planet has passed in front of the star. Kepler focuses light onto 42 light-detecting chips, called CCDs, each of which monitors stars in a different part of the telescope’s field of view. Each CCD is split into two for the purposes of sending data back to Earth, for a total of 84 data channels. Three of these channels are plagued by electronic noise that makes stars in their field of view appear to flicker – “like it’s changing its brightness at a rapid rate”, says Kepler chief scientist William Borucki [New Scientist]. That’s awkward, since the artificial flickers could obscure the real dimming that occurs during a planet’s transit.
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New results are in from the Fermi Space Telescope, which settled into orbit in the summer of 2008, and the findings seem to prove Albert Einstein right once again. Man, that guy was good.
The telescope detected and studied a gamma ray burst, one of the massively bright and powerful explosions that occurs when stars go supernova in distant galaxies. Astronomers were interested in the gamma rays of differing energies and wavelengths that were generated by the explosion, and that raced each other across the universe. After a journey of 7.3 billion light-years, they all arrived within nine-tenths of a second of one another in a detector on NASA’s Fermi Gamma-Ray Space Telescope, at 8:22 p.m., Eastern time, on May 9 [The New York Times].
The researchers were wondering if certain gamma rays with both high energies and short wavelengths would arrive last, at the back of the pack. That would suggest that they had violated one of the principles set out in Einstein’s theory of relativity: that the speed of light is always constant. If researchers could detect a significant lag in some gamma rays, it would also give fresh hope to those ambitious researchers searching for a theory of everything.
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Planets, planets, everywhere! Astronomers have announced the discovery of 32 new planets orbiting distant stars, bringing the list of known exoplanets up to more than 400. The batch of freshly discovered worlds include four that are only five or six times the mass of Earth, an encouraging sign in the quest for a truly Earth-like world that could support life. Researcher Stephane Udry says the discovery is exciting because it suggests that low-mass planets could be numerous in our galaxy. “From [our] results, we know now that at least 40% of solar-type stars have low-mass planets. This is really important because it means that low-mass planets are everywhere, basically” [BBC News].
The discovery was made with the HARPS telescope at the European Southern Observatory’s facility in Chile. HARPS uses the so-called wobble method to detect planets, in which researchers look for the slight quiver in a star’s regular movements that indicates the gravitational tug of an orbiting planet.
Planets were found around a surprising variety of star types. Gas giant planets were found orbiting “metal-poor” stars — those lacking in elements other than hydrogen and helium — which until now had been considered unlikely places for planets to form [Washington Post]. Researchers also located four exoplanets around relatively cool, small stars known as M-class red dwarfs, and will continue to examine such stars for signs of Earth-like planets. The team expects to keep spotting planets by the dozen, says Udry: “Nature doesn’t like a vacuum so if there is space to put a planet it will put a planet there” [Reuters].
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Image: European Southern Observatory. Artist’s impression of a newly discovered planet orbiting the star Gliese 667 C, which is part of a triple star system.
Astronomers have found an enormous and diffuse new ring of Saturn that lies far, far beyond the rest of the planet’s famous circlets. Researchers say the new ring is comprised of debris ejected from Saturn’s outlying moon Phoebe during impact. The new discovery also solves a puzzle regarding the curious two-faced appearance of Saturn’s moon Iapetus, whose leading hemisphere is much darker than its trailing side [New Scientist].
The ring, which has claimed the title of largest known ring in the solar system, starts about 3.7 million miles from Saturn and extends outward another 7.4 million miles. Its diameter is equivalent to 300 Saturns lined up side to side. And its entire volume can hold one billion Earths…. “This is one supersized ring” [CNN], says Anne Verbiscer, coauthor of the study published in Nature. The ring has the same orbital tilt as the moon Phoebe–both are tilted at a 27 degree angle from Saturn’s main ring plane–which supports the theory that Phoebe’s ejected dust feeds the ring.
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Astronomers have conclusive evidence that a planet spotted in a star system 500 light years away is rocky and solid, just like Earth. Scientists have long figured that if life begins on a planet, it needs a solid surface to rest on, so finding one elsewhere is a big deal. “We basically live on a rock ourselves,” said co-discoverer Artie Hartzes…. “It’s as close to something like the Earth that we’ve found so far. It’s just a little too close to its sun” [AP].
Yes, for while the exoplanet, Corot-7b, is rocky like Earth and is only about five times more massive than our home planet, it’s hardly our twin. Its close proximity to its star means that it completes an orbit (its “year”) in just 20 hours, and the climate extremes are punishing. Temperatures soar above 2,000 degrees on its day side and sink to minus 200 degrees on the night side. It means the surface could be covered with molten lava or boiling oceans and it certainly could not hold any form of life as we know it [Scientific American].
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The Mount Wilson Observatory has allowed astronomers to gaze at the heavens for more than a century from a peak in the San Gabriel Mountains, just northeast of Los Angeles, but the devastating conflagration known as the Station Fire that ripped through the Angeles National Forest over the past week had stargazers wondering if the historic facility was about to go up in smoke. The flames got so close at one point that firefighters abandoned the facility, but now L.A. County Deputy Fire Chief Jim Powers has assured astronomers that he foresees “another hundred years for Mount Wilson Observatory.” This is the story of how firefighters saved the birthplace of modern astronomy as well as a virtual forest of communication towers that serve the region [AP].
On Monday night, the scene was grim. The observatory had been hastily evacuated that day, and only two-dozen firefighters stood overnight sentry, positioned along the gloomy perimeters of the observatory and towers. A greater number might have been deployed, but there were more pressing priorities in the urban elevations — the protection of hillside homes [Los Angeles Times]. By daybreak, fire chiefs made the call to retreat from the mountaintop, where firefighters could easily be trapped by the oncoming flames. “It’s not worth dying for,” said Los Angeles County Fire Department Battalion Chief Steve Martin [Los Angeles Times].
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Looking for the best place on Earth to gaze at the stars? Scientists have identified the exact spot on the planet that provides the greatest view of the heavens. The location, called Ridge A, is deep in the Antarctic interior, according to a study published in the Publications of the Astronomical Society.
You’ll want to bundle up, though, because the 13,297-foot-high location has an average winter temperature of about -94 degrees Fahrenheit. It’s so inhospitable that researchers say that no human has ever set foot on Ridge A.
To search for the perfect site to take pictures of the heavens, a U.S.-Australian research team combined data from satellites, ground stations and climate models in a study to assess the many factors that affect astronomy — cloud cover, temperature, sky-brightness, water vapor, wind speeds and atmospheric turbulence [LiveScience]. Scientists believe that a telescope set in place on Ridge A could take pictures as well as the Hubble Space Telescope, which is orbiting the Earth, thanks to the area’s lack of wind and weather.
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Image: flickr / es0teric
The dormant Hawaiian volcano Mauna Kea has been selected as the site of the world’s largest telescope, the much-anticipated Thirty Meter Telescope. Its enormous mirror will have nine times the light-gathering capacity as the biggest telescopes operating today, and will be able to look back to the beginnings of the universe. “It will really provide the baby pictures of the universe” [Honolulu Advertiser], says Charles Blue, a spokesman for the Thirty Meter Telescope Observatory Corporation.
The telescope’s mirror, stretching 30 meters (almost 100 feet) in diameter, will be so large that it should be able to gather light that will have spent 13 billion years traveling to earth. This means astronomers looking into the telescope will be able to see images of the first stars and galaxies forming — some 400 million years after the Big Bang [AP]. The telescope is expected to be completed by 2018, but it may not be the world’s largest for long–the European Extremely Large Telescope is scheduled for completion around the same time, and will boast a 138-foot mirror.
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The sun has been surprisingly quiet lately, and until now astronomers couldn’t figure out why. An 11-year cycle governs solar flares and sunspots, and researchers knew that we were at the end of a cycle in a “solar minimum” or quiet period–but that somnolence has continued for an extra year beyond the point at which researchers expected sunspot activity to resume. Comments Australian astronomer Phil Wilkinson: “We have had a drought of sunspots…. This is the longest period the sun has been quiet since the start of the Space Age. Seeing the sun doing nothing is really exciting,” he said, adding it made physicists wonder how little they really understood [Sydney Morning Herald].
Now, new observations announced at a meeting of the American Astronomical Society reveal a possible explanation: “sluggish” solar jet streams 4,350 miles below the surface of the sun. Every 11 years, the sun simultaneously generates twin streams of plasma at each of its poles. Unlike the jet streams on Earth, the solar versions are magnetized and travel only toward the equator. This migration takes place very slowly–at about 10 kilometers per hour. For reasons still not understood, when the streams reach 22 degrees of latitude, north and south, they touch off a new solar cycle, and the sunspots reappear [ScienceNOW Daily News].
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Only 20 years ago, astronomers were arguing over whether a colleague had discovered the first exoplanet–a planet beyond our solar system that is in orbit around an alien sun. Fast forward to the present day, and researchers have now spotted more than 300 exoplanets in our Milky Way galaxy, and the new topic of discussion is whether a group of astronomers has detected the first extragalactic planet in the Andromeda galaxy.
A new study to be published in the Monthly Notices of the Royal Astronomical Society explains that it should be possible to identify extragalactic planets with the technique of gravitational microlensing, in which a distant source star is briefly magnified by the gravity of an object passing in front of it. This technique has already found several planets in our galaxy, out to distances of thousands of light years. Extending the method from thousands to millions of light years won’t be easy, says [study coauthor] Philippe Jetzer, … but it should be possible [New Scientist]. In fact, it may have already been accomplished.
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Planet-hunters have yet another tool to use in their quest to discover distant worlds that could harbor life. A group of astronomers has discovered a gas giant with six times the mass of Jupiter orbiting a small, weak red dwarf star by means of a method called astrometry. It’s the first time researchers have spotted an exoplanet with this technique, which they say could be useful for finding a different type of planet than those detected by tried and true methods.
Most of the 300-plus known extrasolar planets have been found by tracking changes in a star’s light output over time. The most prolific approach, the radial velocity method, looks for shifts in that light caused by the Doppler effect as the tug of an orbiting planet pulls the star nearer and more distant to us along our line of sight. The other approach, the transit method, tracks the periodic dimming of a star caused by a planet passing in front of it [Scientific American]. In contrast, astrometry doesn’t focus on a star’s light output, but rather on its precise location.
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Water is crucial to the only kinds of living things we’ve ever seen, so the presence of the wet stuff on another planet could be a sign of potential life. Unfortunately, scientists have been unsure how to detect water on distant planets. But the Deep Impact spacecraft has recently given researchers a glimpse of what a wet planet looks like from far away by turning its detectors onto the Earth itself.
Essentially, Deep Impact has turned Earth into a case study of a planet replete with water. The spacecraft, which is 30 million miles away, or halfway to Venus from Earth, has shown scientists how overlapping continents and bodies of water alter the way that light of seven different wavelengths reflects off of the planet’s surface. When scientists observed light from Earth twice over a 24-hour period, they found small deviations in colour caused when clouds or oceans rotated into view. The results mean they should now be able to recognise similar features on alien planets using giant telescopes in space [Scientific American].
The researchers were able to identify key features that could help identify a water-laden planet using telescopes, chemical-analyzing spectrographs and other instruments…. As Earth completed a 24-hour rotation, the change in brightness varied by about 30 percent up and down. The shift is caused by the planet’s reflectivity as the sun [alternately] shines on oceans and then continents [Discovery News]. The findings will be published in an upcoming issue of Astrophysical Journal.
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Four hundred years ago, Galileo observed the phases of Venus as the planet orbited our sun and caught its light in different ways, helping to disprove the idea that all celestial bodies twirled around the Earth. Now, the professional descendants of Galileo have observed the phases of an exoplanet for the first time, observing the distant planet in the act of orbiting a foreign star.
The planet, CoRoT-1b, is about 1,600 light years away from Earth, and was discovered about 2 years ago. It’s a “hot Jupiter,” a class of exoplanets that are the size of Jupiter but orbit very closely to their stars (CoRoT-1b orbits its star in just 36 hours). Hot Jupiters are expected to be tidally locked, with one side always facing their stars, the other permanently dark (our own moon is tidally locked with the Earth, only showing its “near side” to us) [SPACE.com].
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This morning, 350 miles above the Atlantic Ocean, a tender goodbye took place. Astronauts aboard the Atlantis space shuttle released the Hubble Space Telescope to conclude the telescope’s fifth and final repair mission. The better-than-new observatory is expected to send back breathtaking images and mind-rattling information about the universe for another five to seven years. As the NASA officials in charge of the telescope put it: “Hubble is now ready to resume its role as humankind’s most powerful eyes on the universe” [AP].
During this mission, Atlantis astronauts spent more than 36 hours over five marathon spacewalks to make upgrades and outfit Hubble with new instruments. These included a panchromatic wide-field camera that should be able to see objects formed just 500 million years after the universe’s birth in the big bang explosion some 13.7 billion years ago [Reuters]. But there were occasional glitches: When a bolt wouldn’t come free on the Sunday spacewalk, astronaut Mike Massimino had to resort to brute force, jerking the railing that it held in place until the bolt snapped. There was also an ill-timed incident this morning involving an antenna.
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