 |
 |
 |
 |
 |
 |
 |
 |
 |
|
Fri, 27 Aug 2010 Scientists working with NASA's Kepler satellite reported Thursday that they might have spotted a planet just 1.5 times the diameter of Earth around a Sun-like star 2,000 light-years away. "We're still in the process of confirming this candidate is a planet," said Matthew Holman, of the Harvard-Smithsonian Center for Astrophysics, at a NASA-sponsored news conference on Thursday. Dr. Holman is the lead author of an article describing the discoveries that the journal Science published on its Web site. This is the first announcement of a candidate Earth-size planet by the Kepler mission, which in March 2009 launched a one-ton spacecraft to search for planets like ours that just might harbor life. The planet was among more than 700 candidate planets that the team announced in June. If it is made of similar stuff as Earth, its mass would be three to four times as much. Wed, 25 Aug 2010 Astronomers have discovered a planetary system containing at least five planets that orbit a star called HD 10180, which is much like our own Sun. The star is 127 light years away, in the southern constellation of Hydrus. The researchers used the European Southern Observatory (Eso) to monitor light emitted from the system and identify and characterise the planets. They say this is the "richest" system of exoplanets—planets outside our own Solar System—ever found. Christophe Lovis from Geneva University's observatory in Switzerland was lead researcher on the study. He said that his team had probably found "the system with the most planets yet discovered." This also highlights the fact that we are now entering a new era in exoplanet research—the study of complex planetary systems and not just of individual planets," he said. Mon, 28 Jun 2010 Giant planets with wonky orbits mostly circle blistering-hot stars, two new studies find. This pattern could explain why some "hot Jupiters"--planets from a third to 12 times the mass of Jupiter that sit scorchingly close to their stars--orbit the way their star spins, while others tilt so far that they orbit backward. "It's a possible resolution of what would otherwise be a weird fluke," said astronomer Joshua Winn of MIT, a co-author of one of the new studies. Originally, astronomers thought planets formed from a swirling disk of gas and dust that revolved around a central star like a record. When the disk's material cooled and congealed, the resulting planets all marched in line with the star's equator. Hot Jupiters were supposed to have formed around where Jupiter sits in our solar system, then spiraled calmly inward by exchanging gravitational energy with the disk, a process called migration. The first batch of extrasolar planets discovered fit this picture, reassuring astronomers that their model was right. Fri, 25 Jun 2010 A long-studied planet orbiting a star 150 light-years away has been given a new look, thanks to a novel method of studying extrasolar planets from Earth. The planet, which goes by the unmemorable name of HD 209458 b, became in 1999 the first world spotted as it passed in front of its host star, an event known as a transit that reveals the fortuitously aligned planet's presence through the slight dimming of the star. Even though astronomers cannot see a transiting planet directly--its presence is inferred by shifts in the host star's apparent brightness and confirmed by other effects--they can track the spectrum of starlight through the object's orbit to isolate contributions from the planet. In the more than 10 years since the discovery of HD 209458 b researchers have identified several molecules in its atmosphere, including water vapor, methane and carbon dioxide. Now a study in the June 24 Nature, based on high-resolution measurements of carbon monoxide in the planet's upper atmosphere, is providing a new look at the planet, revealing that winds tear through the atmosphere at several thousand kilometers per hour. Wed, 14 Apr 2010 Maybe Frank Drake was right. Nearly half a century ago, the American astronomer postulated that, based on pure statistical probability, the Milky Way could be teeming with Earth-like planets. Now observations of formerly sunlike stars called white dwarfs suggest that the overwhelming majority of them once harbored at least one rocky world. And because sunlike stars could account for up to half of the Milky Way's population of several hundred billion suns, that means hundreds or even thousands of civilizations might inhabit our galaxy. The question of how many rocky worlds exist in the galaxy has perplexed astronomers for the better part of a century. Even now, technology hampers the search. Astronomers are years away from being able to image another Earth directly. Mon, 29 Mar 2010 In work that advances medicine's ability to search our genes for the causes of disease, researchers from Wisconsin have sequenced a young boy's genes and pinpointed the genetic trigger of an illness that had baffled doctors. The study, presented to 150 doctors and researchers at the annual meeting of the American College of Medical Genetics, follows a series of recent scientific papers exploring the potential of DNA sequencing as a tool to diagnose disease. But unlike most of the papers, the Wisconsin case didn't stem from a scientific inquiry, but rather an attempt to help a very sick young boy. Wed, 10 Feb 2010 Oceans of lava might bubble on its surface. Hot pebbles may rain down from the sky. But the extrasolar planet CoRoT-7b is considered to be the most Earthlike world yet found outside our solar system. A recent study, however, suggests that Earth might not be the best basis for comparison. Instead, the authors argue, CoRoT-7b is the first in a new class of exoplanets: a super-Io. Like Jupiter's moon Io, CoRoT-7b could easily be in the right kind of orbit to experience what's known as tidal heating, according to study co-author Rory Barnes of the University of Washington in Seattle. Fri, 5 Feb 2010 Astronomers have used a new ground-based technique to study the atmosphere of a planet outside our Solar System. The work could assist the search for Earth-like planets with traces of organic, or carbon-rich, molecules. Gases have previously been discerned on exoplanets before, but only by using space-based telescopes. Astronomers reporting in Nature say their method of spotting methane gas on exoplanets could be extended to many other, ground-based telescopes. Methane was first spotted on an exoplanet named HD 189733b in 2008 by a group led by Mark Swain of Nasa's Jet Propulsion Laboratory in the US. Wed, 13 Jan 2010 It seems increasingly likely that, as they stare at the heavens, astronomers are going to find an Earth out there, or at least something that they can plausibly claim is a rocky planet where water could splash at the surface and—who knows?—harbor some kind of life. But it's also clear that, when they make their big discovery, the astronomers might want to hire movie director James Cameron to help with the special effects. The roughly 400 planets that astronomers have found outside our solar system have not been Earthlike by any stretch of the imagination. Most are hot Jupiters, which is to say they're gas giants in scorching orbits. They've also been pretty much invisible, their presence inferred from fluctuations in starlight. The planet emerges from the data. Astronomers will announce a new planet find with a graph, typically with a nice curving line that represents the periodic changes in starlight associated with the orbiting body. There are no pictures. Which is fine for scientists. Tue, 5 Jan 2010 NASA's Kepler Space Telescope has detected its first five exoplanets, or planets beyond our Solar System. The observatory, which was launched last year to find other Earths, made the discoveries in its first few weeks of science operations. Although the new worlds are all bigger than our Neptune, the US space agency says the haul shows the telescope is working well and is very sensitive. The exoplanets have been given the names Kepler 4b, 5b, 6b, 7b and 8b. They were announced at an American Astronomical Society meeting in Washington DC. The planets range in size from an object that has a radius four times that of Earth, to worlds much bigger than even our Jupiter. Tue, 22 Dec 2009 The wide dishes, 20 feet across and raised high on their pedestals, creaked and groaned as the winds from an approaching snowstorm pushed into this highland valley. Forty-two in all, the radio telescopes laid out in view of some of California's tallest mountains look otherworldly, and now their sounds conjured up visions of deep-space denizens as well. The instruments, the initial phase of the planned 350-dish Allen Telescope Array, are designed to systematically scan the skies for radio signals sent by advanced civilizations from distant star systems and planets. Fifty years after it began—and 18 years since Congress voted to strip taxpayer money from the effort—the nation's search for extraterrestrial intelligence is alive and growing. Fri, 18 Dec 2009 Astronomy is the science of the exotic, but the thing that astronomers most want to find is the familiar: another planet like Earth, a hospitable face in a hostile cosmos. The Kepler spacecraft, which was launched last March, is their best instrument yet for discovering Earth-like planets around sunlike stars, as opposed to the giant planets that have been planet finders' main harvest so far. Many predict that 2010 will be the year of exo-Earths. But if the giant planets, which looked nothing like what astronomers had expected, are any indication, those Earths may not be so reassuringly familiar either. It has dawned on theorists in recent years that other Earth-mass planets may be enormous water droplets, balls of nitrogen or lumps of iron. Name your favorite element or compound, and someone has imagined a planet made of it. The spectrum of possibilities depends largely on the ratio of carbon to oxygen. Thu, 17 Dec 2009 Call it Sauna World. Astronomers said Wednesday that they had discovered a planet composed mostly of water. You would not want to live there. In addition to the heat—400 degrees Fahrenheit on the ocean surface—the planet is probably cloaked in a crushingly dank and dark fog of superheated steam and other gases. But its discovery has encouraged a growing feeling among astronomers that they are on the verge of a breakthrough and getting closer to finding a planet something could live on. "This probably is not habitable, but it didn't miss the habitable zone by that much," said David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, who led the team that discovered the new planet and will reports its findings on Thursday in the journal Nature. Tue, 8 Dec 2009 Strike one planet from the list of 400-odd found around stars in other solar systems: a proposed planet near a star some 6 parsecs from Earth may not exist after all. The finding is also a strike against a planet-seeking strategy called astrometry, which measures the side-to-side motion of a star on the sky to see whether any unseen bodies might be orbiting it. Ground-based astrometry has been used for more than a century, but none of the extrasolar planets it has detected has been verified in subsequent studies. In May, Steven Pravdo of the Jet Propulsion Laboratory in Pasadena, California, and his colleagues raised fresh hopes for the technique when they announced an exoplanet, six times more massive than Jupiter, orbiting VB10, a star about one-thirteenth the mass of the Sun, using a telescope at the Palomar Observatory in southern California. But now a group led by Jacob Bean at the Georg-August University in Gottingen, Germany, has used a different approach, and found nothing. "The planet is not there," says Bean. Fri, 4 Dec 2009 Astronomers have published an image of the coolest planet outside our solar system that has been pictured directly. The new find is more similar to our own Solar System than prior pictured exoplanets, in terms of the parent star's type and the planet's size. However, the surface temperature is a scorching 280-370C, and could still prove to be a brown dwarf star. The results, published in Astrophysical Journal, were obtained by a new camera on the Subaru telescope in Hawaii. Thu, 12 Nov 2009 Astronomers have identified an easy-to-measure chemical fingerprint for determining which sunlike stars are likely to host planets. The marker—a low abundance of lithium in the atmosphere of these stars—could prove an invaluable guide for planet hunters trying to determine which of the myriad sunlike stars to select for long-term study. In their study, Garik Israelian of the Instituto de Astrofisica de Canarias in Tenerife, Spain, and his colleagues relied on data from a census of 133 sunlike stars, most of them monitored for several years with the European Southern Observatory's HARPS spectrograph at the La Silla observatory in Chile. Tiny wobbles in the motions of 30 of these stars indicate the gravitational tug of unseen planets. In the Nov. 12 Nature, Israelian and his colleagues report that the majority of sunlike stars hosting planets in the HARPS sample have, on average, one-tenth the amount of lithium of those without planets. It's been known for decades that Earth's sun shows such a depletion. Tue, 20 Oct 2009 European astronomers have found 32 new planets outside our solar system, adding evidence to the theory that the universe has many places where life could develop. Scientists using the European Southern Observatory telescope didn't find any planets quite the size of Earth or any that seemed habitable or even unusual. But their announcement increased the number of planets discovered outside the solar system to more than 400. Six of the newly found planets are several times bigger than Earth, increasing the population of so-called super-Earths by more than 30 percent. Most planets discovered so far are far bigger, Jupiter-sized or even larger. Thu, 17 Sep 2009 Astronomers have finally found a place outside our solar system where there's a firm place to stand—if only it weren't so broiling hot. As scientists search the skies for life elsewhere, they have found more than 300 planets outside our solar system. But they all have been gas balls or can't be proven to be solid. Now a team of European astronomers has confirmed the first rocky extrasolar planet. 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 Hatzes, director of the Thuringer observatory in Germany. "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." Wed, 29 Jul 2009 Exobiologists are looking for every conceivable sign of alien life and habitable planets. But there may be clues that few have thought of. Taylor Perron, a geophysicist at the Massachusetts Institute of Technology, thinks his research team has found one in the familiar, repeating pattern of ridges and valleys that shape many landscapes on Earth. Their report, published July 23 in the journal Nature, shows that the activity of living creatures help sculpt their terrain. It helps establish the spacing between ridges and valleys. Wed, 3 Jun 2009 Researchers for half a century have tried—and failed—to use the motion of stars moving across the sky to discover planets that lie beyond the solar system. Now a team has finally used the method, known as astrometry, to find one of these orbs. The newfound extrasolar planet, six times heavier than Jupiter, orbits the low-mass star VB 10 some 20 light-years from Earth ... The traditional method of identifying extrasolar planets ... relies on tracking the velocity of a parent star along the line of sight to Earth—rather than across the sky. Because an orbiting planet pulls its parent star ever so slightly to and fro, the star's line-of-sight motion speeds up and slows down periodically, revealed by telltale shifts in the color of starlight recorded from Earth. This technique, known as the wobble or Doppler shift method, detects heavyweights that lie close to their star most easily ... In contrast, the astrometric method ... pins down the exact mass of a planet. The method favors massive planets that lie far from a parent star, since such planets cause a star to move by the largest amount across the sky. Mon, 1 Jun 2009 The nearest Earth out there in space? It might be right next door, galactically speaking. Two teams of astronomers, one from the United States and one from Europe, are in a race to find a planet orbiting our near neighbors Alpha Centauri A and Alpha Centauri B, twin stars that appear from Earth as a single point of light. "I'm betting that there are planets like Earth or Mars or Venus around either or both of those stars, and the only question is whether we'll be able to detect them," said Debra Fischer, an astronomer at San Francisco State University. Backed with U.S. government funding, she is using a telescope in Chile to assemble 100,000 observations of the Centauri system. Thu, 21 May 2009 ...Astronomers have always suspected that planets might orbit stars other than our sun. We imagined, though, that we would find systems much like our own solar system, centered on a star much like the sun. Yet when a flood of discoveries began 15 years ago, it was apparent right away that extrasolar planetary systems can differ dramatically from our solar system. The first example was the sunlike star 51 Pegasi, found to have a planet more massive than Jupiter on an orbit smaller than that of Mercury. As instruments became more sensitive, they found ever stranger instances. The sunlike star HD 40307 hosts three planets with masses between four and 10 Earth masses, all on orbits less than half the size of Mercury's. The sunlike star 55 Cancri A has no fewer than five planets, with masses ranging from 10 and 1,000 Earth masses and orbital radii ranging from one tenth that of Mercury to about that of Jupiter. Planetary systems imagined in science fiction scarcely compare. Wed, 13 May 2009 Things were not looking so good for alien life in 1976, after the Viking I spacecraft landed on Mars, stretched out its robotic arm, and gathered up a fist-size pile of red dirt for chemical testing. Results from the probe's built-in lab were anything but encouraging. ... What a difference 33 years make. Back then, Mars seemed the only remotely plausible place beyond Earth where biology could have taken root. Today our conception of life in the universe is being turned on its head as scientists are finding a whole lot of inviting real estate out there. As a result, they are beginning to think not in terms of single places to look for life but in terms of "habitable zones"—maps of the myriad places where living things could conceivably thrive beyond Earth. Such abodes of life may lie on other planets and moons throughout our galaxy, throughout the universe, and even beyond. Tue, 12 May 2009 One of the most remarkable features of the solar system is the variety of planetary atmospheres. Earth and Venus are of comparable size and mass, yet the surface of Venus bakes at 460 degrees Celsius under an ocean of carbon dioxide that bears down with the weight of a kilometer of water. Callisto and Titan—planet-size moons of Jupiter and Saturn, respectively—are nearly the same size, yet Titan has a nitrogen-rich atmosphere thicker than our own, whereas Callisto is essentially airless. What causes such extremes? If we knew, it would help explain why Earth teems with life while its planetary siblings appear to be dead. Knowing how atmospheres evolve is also essential to determining which planets beyond our solar system might be habitable. Wed, 22 Apr 2009 The most Earth-sized planet and the most temperate planet known beyond our solar system both circle a dim red star 21 light-years away. These discoveries, announced yesterday at a meeting in England, moved astronomers a step closer to their dreams of finding other planets capable of supporting life as we understand it. Since 1995, scientists have found more than 350 planets orbiting other stars, but most suffer from the same problems that make our neighbors in the solar system so inhospitable. Many of the so-called extrasolar planets orbit so close that their stars would sterilize their surfaces. Others are jumbo "gas giants," like Jupiter, and therefore unlikely to have solid surfaces. Astronomers suspect that Earthlike planets are out there but that they are nearly impossible to detect with current technology. Wed, 22 Apr 2009 In the search for Earth-like planets, astronomers zeroed in on two places that look awfully familiar to home. One is close to the right size. The other is in the right place. European researchers said they not only found the smallest exoplanet ever, called Gliese 581 e, but realized that a neighboring planet discovered earlier, Gliese 581 d, was in the prime habitable zone for potential life. "The Holy Grail of current exoplanet research is the detection of a rocky, Earth-like planet in the 'habitable zone,'" said Michel Mayor, an astrophysicist at Geneva University in Switzerland... Gliese 581 e is only 1.9 times the size of Earth—while previous planets found outside our solar system are closer to the size of massive Jupiter, which NASA says could swallow more than 1,000 Earths. Every weekday, Sigma Xi, the Scientific Research Society, selects a set of significant and interesting science-related news articles from the mainstream media. The news stories featured here are selected from Sigma Xi's daily Science in the News e-mail. http://www.mediaresource.org/news.instruct.shtml |
|||||||||||
|
|||||||||||
| |||||||||||
© | Created April 2009 |
|||||||||||
