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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Yesterday, about 350 miles above western Australia, two massively expensive pieces of space hardware rendezvoused in a delicate orbital dance. The space shuttle Atlantis arrived at the Hubble Space Telescope for the telescope’s fifth and final upgrade, and met the telescope in orbit as it circled the Earth at 17,200 miles per hour. With mission commander Scott Altman at the controls, Atlantis eased up within 30 feet of NASA’s flagship observatory, bringing the ship close enough for a capture attempt. Mission specialist Megan McArthur limbered up the shuttle’s robot arm and used snares at its end to latch on to a pin-like grapple fixture on the side of the gleaming telescope. “Houston, Atlantis. Hubble has arrived onboard Atlantis,” said Altman [Florida Today blog].
The astronauts audibly gasped as they drew up to the 12-ton telescope. “Just looking out the window here, and it’s an unbelievably beautiful sight,” said John M. Grunsfeld, a veteran astronaut. “Amazingly, the exterior of Hubble, an old man of 19 years in space, still looks in fantastic shape.” Dr. Grunsfeld, who is on his third Hubble repair trip, was one of the last humans to see the telescope in March 2002 and arguably knows it better than anyone on or above Earth [The New York Times].
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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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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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