Mix one part science fiction, one part misunderstood Mayan history, one part Hollywood movie hype, and quite a bit of public credulity, and what do you get? A new wave of doomsday hysteria that is causing scientists to step forward to reassure the public that the world is not, actually, going to end on December 21, 2012.
The rumors flying around the Internet offer a number of ways in which the world may end, including a planetary collision and changes to the Earth’s rotation or magnetic field, but they all agree on that date of doom. You can bet that the viral marketing campaign promoting the upcoming planetary disaster movie 2012 has a little something to do with the recent uptick in paranoia.
“Two years ago, I got a question a week about it,” said NASA scientist David Morrison, who hosts a website called Ask an Astrobiologist. “Now I’m getting a dozen a day. Two teenagers said they didn’t want to see the end of the world so they were thinking of ending their lives” [Los Angeles Times]. In response, Morrison put together a list [pdf] of 10 frequently asked questions about the potential for apocalypse, and refuted them one by one. The clamor has grown so loud that Morrison coined a new word to describe the phenomenon: “cosmophobia,” a fear of the cosmos.
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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.
In a star system 330 light years away from Earth, astronomers have spotted a giant planet that booms around its parent star in tight, fast circles, completing an orbit (the planet’s “year”) in less than one Earth day. The exoplanet, known as Wasp-18b, is so close to its star that researchers say it appears to be spiraling inwards to its fiery doom. But the odds of seeing a planet in its death throes are so low that researchers are searching for alternate explanations, and say the planet could force scientists to rethink established ideas about planetary forces known as tidal interactions [National Geographic News].
The planet is known as a “hot Jupiter,” meaning that it’s a massive gas giant like our own solar system’s Jupiter, but it orbits in close proximity to its star. Current theories say that such a massive planet so close to its star should be pulling on the host star, creating a tidal effect similar to the moon’s pull on Earth. At that range the planet’s pull would be so strong that it would drain energy from its orbit, causing the planet to rapidly fall into the star [National Geographic News]. But if that’s the case, the planet would meet its death in less than a million years. Since the star system is thought to be about 1 billion years old, the odds of catching the planet in its last stages are one in a thousand.
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Scientists have spied a new exoplanet–and not only is it the biggest one yet, but it’s also moving the wrong direction. Unlike other planets, which orbit the same way their stars rotate, WASP-17 moves the opposite way, according to a study published in Astrophysical Journal.
Planets are born from the same ball of rotating gas that creates their parent star, which is why they usually orbit — and spin — in the same direction as their star. While WASP-17 is the first planet known to orbit backwards, some planets in our own solar system, such as Venus, are spinning backwards [Wired]. WASP-17’s backwards motion is known by astronomers as a retrograde orbit.
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NASA’s Kepler spacecraft has only been in operation for 10 days, but it’s already spotted a planet, according to a report in Science. That leaves experts optimistic about the craft’s potential to find other Earth-like planets.
Scientists already knew that the planet Kepler found existed. It’s called HAT-P-7b, and it’s a planetary body that’s too heavy and too hot to support life. Still, Kepler gave scientists new details about the planet, including that the planet has a hazy, ozone-like atmosphere. The analysis proves that Kepler’s onboard telescope and light-detecting instruments are at least 100 times more precise than the ground-based detectors that originally found HAT-P-7b [L.A. Times], because Earth-based telescopes must wrestle with distortion from the atmosphere, while Kepler only looks through the clear near-vacuum of space.
Scientists say that Kepler’s capabilities should be sufficient to find Earth-like planets in the “habitable zone” of a star system–that is, the ring where temperatures climb high enough to allow liquid water to exist, but aren’t so scorching as to burn up the surface of the planet.
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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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Astronomers still haven’t discovered Earth’s twin orbiting another star out in the cosmos, but they’re beginning to find worlds with a passing resemblance to our own. New studies of the red dwarf star Gliese 581 have revealed a small, rocky exoplanet with only twice the mass of Earth, and have also shed new light on a larger planet orbiting farther out, which researchers now say could have liquid water. Team member Stephane Udry believes that the larger planet could have a “large and deep” ocean. “It is the first serious ‘water-world’ candidate,” Udry said [AP].
Researchers had previously discovered three planets orbiting the star, including the potential water world, Gliese 581 d. Based on earlier observations, researchers thought that the planet took 83 days to orbit its star, which would indicate that the planet was too far from the red dwarf’s weak heat to have liquid water. But more extensive observations have shown that the planet actually has an orbital period of 66 days, putting the planet just inside the star’s “habitable zone.” Lead researcher Michel Mayor says the planet may be warm enough to bear oceans that are thousands of miles deep. “Maybe this is the first of a new class of ocean planets. That is my favourite interpretation,” says Mayor. “Whether there is life or not, I don’t know” [New Scientist]. However, not everyone is convinced that Gliese 581 d is wet and wild. Other experts say it’s more likely to be an ice giant, like Neptune and Uranus.
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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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Astronomers are hoping to catch a glimpse of debris that could be leftover from a cosmic collision between our Earth and a Mars-sized planet called Theia–if, in fact, it existed at all. “It’s a hypothetical world. We’ve never actually seen it, but some researchers believe it existed 4.5 billion years ago — and that it collided with Earth to form the moon,” said Mike Kaiser, a NASA scientist [SPACE.com].
The research will be done with the two Stereo spacecraft that are on their way to observe the sun; on their way they’ll have a chance to do some “bonus science,” as one researcher called it. The spacecraft are passing through two regions of space, called Lagrangian points, where the gravity from the Earth and the sun combine to form wells that tend to collect solar system detritus…. Scientists think Theia may even have formed in one of these gravitational points of balance from the accumulation of flotsam that had built up there [SPACE.com].
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On Friday night, a Delta 2 rocket blasted off from the Kennedy Space Center and roared into space carrying a satellite that will search the heavens for Earth-like planets. The craft, Kepler, named after the German astronomer Johannes Kepler, who discovered the planetary laws of motion, is to spend the next three and a half years in an orbit around the Sun, where it will count planets by looking for the tiny blips in starlight caused by planets eclipsing their suns [The New York Times].
The $600 million satellite will stare into a region of the Milky Way that’s thick with stars, in the direction of the constellations Cygnus and Lyra. While Kepler is expected to identify many new planets beyond our solar system, known as exoplanets, the real prize would be to find rocky planets in the “habitable zone” around a star, where conditions might be right for life as we know it. “The habitable zone is where we think water will be,” Bill Borucki, Kepler principal investigator at NASA Ames, says in a video on the space agency’s Kepler site. “If you can find liquid water on the surface we think we may very well find life there. So that zone is not too close to the star, because it’s too hot and water boils, and not too far away where the water is condensed…a planet covered with glaciers. It’s the Goldilocks zone–not too hot, not too cold, just right for life” [CNET].
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While astronomers have found more than 300 planets beyond our solar system in the last 15 years, none of those “exoplanets” has been a likely candidate for extraterrestrial life. The exoplanets discovered thus far are all either too close to the hot sun or too far away and therefore too frigid to host life as we know it. But Alan Boss says it’s just a matter of time before we find Earth-like planets in the “Goldilocks zone”: he calculates that 100 billion of them may exist within our own Milky Way galaxy. And NASA’s Kepler satellite, which is expected to launch on March 5, may be the key to finding them, he says.
Boss, an astrophysicist and author of the new book “The Crowded Universe: The Search for Living Planets,” says that if any of the billions of Earth-like worlds he believes exist in the Milky Way have liquid water, they are likely to be home to some type of life. “Now that’s not saying that they’re all going to be crawling with intelligent human beings or even dinosaurs,” he said. “But I would suspect that the great majority of them at least will have some sort of primitive life, like bacteria or some of the multicellular creatures that populated our Earth for the first 3 billion years of its existence” [CNN].
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A rocky world about twice the size of Earth has been detected orbiting a sun-like star 390 light years away from our solar system. While the “super-Earth” is hot and inhospitable to life as we know it, its discovery puts researchers firmly on the path towards finding other habitable planets. “For the first time, we have unambiguously detected a planet that is ‘rocky’ in the same sense as our own Earth” [Wired News], said project scientist Malcolm Fridlund. The exciting find was made by the CoRoT satellite, which was launched by the French space agency to scan the skies for exoplanets (planets outside our solar system). The results were announced at a CoRoT symposium in Paris.
CoRoT team member Suzanne Aigrain explains that the planet is so close to its parent star that it orbits around it once every 20 hours, and is subject to inferno-like conditions. “It’s likely that there is a solid surface somewhere,” says Aigrain. But the extreme surface temperatures of around 1000°C [around 1800 degrees Fahrenheit] could mean that the planet is host to vast lava fields and boiling oceans. It also may be ‘tidally locked’ to its parent star, leaving one face bathed in constant, searing sunlight while the other is shrouded in continuous night. “It would be a very odd place to set foot on,” she says [Nature News].
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The nearest planetary system to our own has two asteroid belts in addition to a previously known ice belt, according to the latest observations by NASA’s Spitzer Space Telescope. The location and structure of the asteroid belts relative to the system’s central star, Epsilon Eridani, suggests the existence of earth-like planets. “We certainly haven’t seen it yet, but if its solar system is anything like ours, then there should be planets like ours,” says astronomer Massimo Marengo of the Harvard-Smithsonian Center for Astrophysics [USA Today].
The Epsilon Edidani system has long been of interest to astronomers and science fiction fans alike because of its proximity (10.5 light-years) and resemblance to our solar system. The newly discovered asteroid belts give the system an appearance even more like our own. The inner asteroid belt looks identical to ours in terms of material, and it orbits at 3 astronomical units (AU) from Epsilon Eridani — the same distance between the sun and the rocky asteroid belt between Mars and Jupiter. (An astronomical unit equals the average Earth-sun distance of 93 million miles, or about 150 million km.) Epsilon Eridani’s second asteroid belt is 20 AU from the star, or about where Uranus is in relation to our sun, and it is crowded with as much mass as Earth’s moon [Science News]. The outer asteroid belt was captured directly by Spitzer’s infrared cameras and the inner asteriod belt, though too far from the cameras, was indicated by the thermal energy from its infrared emissions.
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