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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Luminaries gathered today at a lab in Livermore, California to toast the opening of the National Ignition Facility, a massive physics experiment aiming to recreate the reaction that takes place in the hearts of stars: nuclear fusion. “Bringing Star Power to Earth” reads a giant banner that was recently unfurled across a building the size of a football stadium [The New York Times]. Scientists are now ready to begin firing the world’s most powerful laser, comprised of 192 separate beams, at a target the size of a match head. Yet for all the celebration and hoopla, doubters note that there’s no guarantee that the fusion researchers will achieve their goal.
The project’s director, Ed Moses, said that getting to the cusp of ignition (defined as the successful achievement of fusion) had taken some 7,000 workers and 3,000 contractors a dozen years, their labors creating a precision colossus of millions of parts and 60,000 points of control, 30 times as many as on the space shuttle. “It’s the cathedral story,” Dr. Moses said…. “We put together the best physicists, the best engineers, the best of industry and academia” [The New York Times]. The project has also cost at least $3.5 billion. NIF’s researchers will spend the next year gradually increasing the energy of the laser beams, and say serious ignition experiments will begin next year.
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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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NASA’s astronauts blasted off just yesterday on a final repair mission to the Hubble Space Telescope, but two space-based telescopes scheduled to rocket into space tomorrow may soon steal the spotlight from the Hubble. The two European Space Agency observatories, named Herschel and Planck, may revolutionize our understanding of how galaxies formed in the young universe, shortly after the Big Bang. Once the telescopes are in place, says ESA science director David Southwood, the next era of space-based astronomy will then be well and truly upon us. “They are at a pivotal point,” he says. “From now on astronomy is going to be done from deep space” [Nature News].
Both telescopes will be carried into space by the same Ariane 5 rocket, which is expected to launch tomorrow from a spaceport in French Guiana. The destination for both telescopes is a remarkable position in space known as the second Lagrangian point (L2). It is one of five gravitational “sweet-spots” around the Sun-Earth system where satellites can maintain station by making relatively few orbital corrections. L2 is some 1.5 million km from Earth on its “night side”. The observatories will circle this point [BBC News], orbiting at different distances to rule out any chance of a collision. At that stable location, the telescopes will be protected from temperature swings; a crucial point since both telescopes must be kept at frigid temperatures to study the “cold universe.”
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At 2:01 this afternoon in Florida, the space shuttle Atlantis is expected to roar off its launch pad and set off toward the orbiting Hubble Space Telescope, for the fifth and final repair mission in the telescope’s history. The countdown timeline is on target, and “Atlantis is ready to fly,” said Charlie Blackwell-Thompson, NASA’s test director…. The 11-day mission will include five spacewalks to refurbish Hubble with state-of-the-art science instruments. After the upgrades, the telescope’s capabilities will be expanded, and its lifetime extended through at least 2014 [CNN].
The current mission carries a higher degree of danger than the space shuttle’s habitual jaunts to the International Space Station. Hubble orbits about 350 miles above Earth, in an area with a higher density of debris. Earlier this year two satellites collided over Siberia, which has increased the risk even more, as junk from that collision drifts lower [ABC News]. While NASA will track orbiting space junk as it always does, the agency has also taken the precaution of getting the space shuttle Endeavor ready for launch on another pad in case a rescue operation is necessary.
NASA will cover the launch live on NASA TV, and DISCOVER’s own Bad Astronomy blogger, Phil Plait, will be posting updates on his breaking news Twitter account.
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Three recent studies raised hopes that physicists had caught the first glimpses of dark matter, but the somewhat contradictory results guarantee that researchers will be puzzling over the issue for some time to come. The latest results come from NASA’s orbiting Fermi Gamma-ray Space Telescope, which was launched last June. The evidence is a reported excess of high-energy electrons and their antimatter counterparts, positrons, which could be created as dark matter particles annihilate or decay [Nature News].
Peter Michelson, principal investigator for the instrument on Fermi that made the detection, cautions that his group is not yet claiming to have found a smoking gun for dark matter. The signal could also come from more mundane sources nearby, such as pulsars, the spinning remnants of supernovae. “But if it isn’t pulsars, it is some new physics,” says Michelson [Nature News]. The new findings are published in Physical Review Letters. Meanwhile, a satellite named PAMELA recently detected higher than expected numbers of positrons, which seems to corroborate the Fermi findings. But results from a balloon experiment conducted high over Antarctica last year add a dash of confusion to the mix.
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When the universe was young, it somehow produced a giant space blob that has astronomers completely puzzled. Researchers have caught sight of an enormous patch of hot hydrogen gas officially known as a Lyman-alpha blob, named for a particular wavelength of light released when an electron loses energy in a hydrogen atom. It spans some 55,000 light years, about half the width of the Milky Way, and it sits some 12.9 billion light years from Earth. That means we are seeing it as it was 12.9 billion years ago, when the universe was just 800 million years old [New Scientist].
The blob poses a cosmological conundrum because astronomers didn’t think such a big cloud could form so early in the history of the universe. Current models hold that between 200 million and one billion years after the Big Bang, the first colossal stars formed, emitting radiation that stripped light elements of their electrons and turned the Universe into a soup of charged particles. Only after this “re-ionisation epoch” did matter as we now know it really start to clump together [BBC News]. Astronomers thought that objects as big as the newly discovered blob would take a great deal of time to gradually grow from the mergers of smaller chunks of matter.
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The Kepler space telescope, which was launched in early March, has taken and sent home its first images of the region in the galaxy where it will spend the next three years searching for Earth-like planets.
The images sent to NASA show a “vast starry field” in the Cygnus-Lyra region of the Milky Way galaxy, according to NASA’s Jet Propulsion Laboratory. One image shows millions of stars in the craft’s full field of view, while two other images zoom in specific sections of that region [Computerworld]. Kepler’s primary mission is to survey stars for regular slight dips in their brightness, a sign that an orbiting planet is blocking the star’s light [Nature blog]. Eventually, the craft will measure the stars’ brightness every half hour.
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The first ever picture of an exoplanet was taken 11 years ago–but no one noticed. Now, in a new study, astronomers have subtracted the starlight from an image taken by the Hubble in 1998, and found the exoplanet by its dim infrared glow. While some exoplanets were detected before 1998, they were discovered indirectly by observing their influence on their parent stars; this was was seen directly.
The new technique has excited researchers wondering how many more new planets can be found in old, archived data. “They’ve dug up old Hubble images and found a planet! Crazy!” Geoff Marcy, an astronomer at the University of California, Berkeley, commented by email. “This will spawn a wild race by astronomers everywhere in the world to dig out their old Hubble images to hunt for planets lost in the rubble of the Hubble” [National Geographic News].
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The mysterious stuff known as dark matter may have left a calling card at the edge of the Earth’s atmosphere where a space-faring satellite named PAMELA could pick it up. Researchers are reporting that PAMELA detected a high number of the subatomic particles called positrons, the positively-charged counterpoints to electrons, which could have been created by collisions between dark matter particles. “PAMELA found a number of positrons much higher than expected,” the mission’s principal investigator Piergiorgio Picozza [said]. “Many think this could be a signal from dark matter” [SPACE.com]. But of course, others think there’s a more mundane explanation.
Dark matter is one of the greatest enigmas in astrophysics: It cannot be observed directly, so researchers have to study its effects on normal matter to try to deduce what it’s made of. The top candidates for dark matter, the heavy but invisible stuff that makes up 23 percent of the universe, are weakly-interacting massive particles. Contrary to their WIMPy name, when two of these particles collide, they annihilate each other in a burst of energy and propel a cloud of matter and antimatter particles into space. The theory has been a favorite of physicists for years, but until now, no one had detected evidence of these collisions [Wired].
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When the universe was young, at least one stellar factory was churning out 1,000 sun-like stars every year, according to a new study. Using an array of telescopes in the French Alps, researchers carefully scrutinised a distant galaxy whose light has taken so long to reach Earth that it appears as it was just 870 million years after the big bang [New Scientist].
The Milky Way currently forms about one sun per year, says study coauthor Chris Carilli, indicating that massive galaxies may have formed very quickly in the universe’s early days.The immense scale of the stellar factory is probably due to the fact that there was a lot more gas around in the early universe, Carilli says. Matter in the universe was indeed much denser soon after the big bang, since space itself has expanded over time [New Scientist].
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For the first time, researchers have watched weather conditions shift on a planet outside our solar system, and say the temperature spikes are out of this world. Normally, the planet is a toasty 980 degrees [Fahrenheit] or so. But in the few hours it whips around its sun the planet gets zapped with mega-heat, pushing the thermometer closer to 2,240 degrees…. When it comes closest to its star, it becomes one giant “brewing storm” [AP].
The gas giant, known as HD 80606b, lies about 190 light-years away in the constellation Ursa Major, and has an extremely elliptical orbit. When it’s closest to its sun, it is barely more than 300,000 miles away – not much more distant than our cold moon is from us. But when the planet is farthest away from its sun and coolest, it’s nearly 70 million miles away. That would be like some object flying somewhere far out between the orbits of Earth and Venus [San Francisco Chronicle]. One complete orbit around its sun takes 111 days.
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The sound of scientific discovery isn’t the clichéd “Eureka!” It’s much more like this recent exclamation from NASA astrophysicist Alan Kogut: “What the heck is this?” Dr. Kogut remembered exclaiming when he first saw the data. “This shouldn’t be here” [The New York Times].
Kogut was looking at a measurement of cosmic radio signals detected by sensitive antennas borne aloft in a balloon, which floated 21 miles above Texas for several hours. While scanning the sky, the instruments found a booming, uniformly distributed radio noise six times louder than anyone had predicted…. The researchers calculate that the radio noise is much too large to be accounted for by the combined emissions of all the galaxies in the universe that emit radio waves [Science News].
When researchers started to contemplate where that signal may have come from, things began to get interesting. It’s possible, says Kogut, that the radio waves may have been emitted during the death of the universe’s first stars. Those stellar pioneers were brutish monsters, so the story believed by most astronomers goes, lumbering clouds of hydrogen and helium hundreds of times more massive than the Sun. They lived fast and bright and died hard, exploding or collapsing into massive black holes less than a billion years after the Big Bang, never to be seen again [The New York Times]. When they collapsed into black holes, they may have spewed forth jets of charged particles that emitted these radio waves.
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Astronomers know that at the heart of every supermassive galaxy is a giant black hole. But new data suggests that the two did not necessarily form in tandem. Instead, black holes may have formed earlier, or at least much more quickly, than their surrounding galaxies. Previous studies had revealed a striking link between black holes and the amount of gas and stars contained in [their] galaxies’ bulges — the regions that lie within a few thousand light-years of the galaxies’ cores. Regardless of their size, the bulges always turned out to be 700 times as massive as the giant black holes at the galaxies’ hubs [Science News]. New measurements of much more distant galaxies, which appear much younger, defy the expected mass ratio. In these younger pairings, the relative mass of the black holes is much greater, hinting that the black holes came first.
Researchers used the Very Large Array radio telescope in New Mexico and the Plateau de Bure Interferometer in France to measure the mass of four distant galaxies as they appeared less than two billions years after the Big Bang. From the motions of the molecular gas, which concentrates in the central part of the galaxies, the team calculated the total amount of mass in the bulges and compared that number to the mass of the central black holes [Science News]. The galactic bulges were only about 30 times more massive than their central black holes. At the American Astronomical Society’s meeting, where the work was presented, astronomer Chris Carilli said, “The simplest conclusion is that the black holes come first and they somehow grow the galaxy around them” [Wired News].
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In the violent heart of our Milky Way galaxy lies a supermassive black hole with a mass equivalent to four million suns. But although the gravitational maw gobbles up anything that gets too close, it can also set up conditions that allow for the birth of new stars just a few light years away, according to a new study. Lead researcher Elizabeth Humphreys says the results, which uncovered what appear to be two young stars as close as seven light-years from the galactic center, were surprising, as that is “one of the last places … you would expect to find stars forming” [Scientific American].
Gas clouds that approach a black hole are usually ripped apart by the intense gravitational forces, but the new finding suggests that the molecular gas at the center of the Milky Way from which the stars form is denser than previously thought. The higher density gas makes it easier for the self-gravity of the condensing cloud to overcome the strong pull of the black hole and to collapse to form new stars [SPACE.com].
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