Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond.
Follow Nancy on Twitter at https://twitter.com/Nancy_A and and Instagram at and https://www.instagram.com/nancyatkinson_ut/
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A bright fireball lit up the sky over parts of Canada and was probably a meteor which may have hit the ground in central Alberta. Reports from all over western Canada said the bright flashes occurred at 5:30 pm MST on Nov. 20. The bolide split the evening sky and fragmented during a series of booming explosions. The image above is from a video taken by Andy Bartlett, who recorded the event from a 10th-floor apartment in Edmonton, Alberta with his Canon A510. Watch the movie here. “The brilliant fireball appeared to be closer than the airplane in the upper right corner of this video,” said Bartlett. Another video was taken by a serendipitously placed surveillance camera. See a news report from a Canadian television station here.
So what was this object?
The possibility of the object being part of a Russian rocket has been ruled out, but astronomers say it will take time for experts to work through videos and photos to find out what exactly occurred. Astronomers need views of the event from at least two sites to triangulate where a meteorite might have hit and where any small pieces could possibly be found. However, it may have burned up completely in the atmosphere. One educator said the object was probably no bigger than the size of a grapefruit as it entered Earth’s atmosphere, probably traveling about 60 km per second.
These are tough economic times for almost everyone, including those of us interested in doing a little backyard astronomy. Even if you’re a casual astronomer or have never done much observing, gazing at the stars might be just the remedy you need to take your mind off any financial woes. Brian Ventrudo, the editor over at One-Minute Astronomer has put together a list of 25 tips and resources that are almost entirely free to help you enjoy astronomy on a tight budget. It’s a great list (it includes a tip to read Universe Today!), so check out Brian’s article, and while you’re there you should subscribe to his newsletter, too.
More about the One-Minute Astronomer…
I’ve subscribe to the One-Minute Astronomer for awhile now, but didn’t know much about the background of the site. So I emailed Brian, and he told me that he developed the website and newsletter to fill a niche where people interested in astronomy can get short easy-to-read articles that help them learn more about astronomy and get more out of their hobby. “A lot of beginners and near-beginners get frustrated after a while and sometimes get information overload,”Brian said, “So my site helps them through by giving useful (usually!) advice and information.”
The One-Minute Astronomer sends out two emails each week to subscribers, and as the name implies, it only takes a minute to read his great advice. That minute is a great “investment” for your interest in astronomy (to continue the economic thread here…!)
About the 25 tips for being a frugal astronomer article Brian said, “Many of my subscribers ask where they can find good free information, so I thought I’d put it all in one place for them. And it’s timely with all the nastiness going on with the economy and markets.”
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Have the floodgates opened for imaging exoplanets?! A team of French astronomers using ESO’s Very Large Telescope have discovered an object located very close to the star Beta Pictoris. This object lies only 8 times the Earth-Sun distance, and it’s likely a giant planet that astronomers suspected was there from the peculiar shape of the disc that surrounds the star. If the object is actually a planet, this would then be the first image of a planet that is as close to its host star as Saturn is to the Sun. This comes on the heels of the news of two of the first direct images ever of exoplanets just last week (see here and here).
Only 12 million years old, the ‘baby star’ Beta Pictoris is located about 70 light-years away towards the constellation Pictor (the Painter). The above image is an infrared image, and visible is the dusty debris disk surrounding the star Beta Pictoris. Debris discs are composed of dust resulting from collisions among larger bodies like planetary embryos or asteroids, and they are a bigger version of the zodiacal dust in our Solar System. Its disc was the first to be imaged — as early as 1984 — and remains the best-studied system. Earlier observations showed a warp of the disc, a secondary inclined disc and infalling comets onto the star. “These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star,” says team leader Anne-Marie Lagrange. “However, probing the very inner region of the disc, so close to the glowing star, is a most challenging task.”
Using an adaptive optics system in infrared wavelengths attached to the VLT, the astronomers were able to discern a feeble, point-like glow well inside the star’s halo. To eliminate the possibility that this was an artifact and not a real object, a battery of tests was conducted and several members of the team, using three different methods, did the analysis independently, always with the same success. Moreover, the companion was also discovered in other data sets, further strengthening the team’s conclusion: the companion is real.
“Our observations point to the presence of a giant planet, about 8 times as massive as Jupiter and with a projected distance from its star of about 8 times the Earth-Sun distance, which is about the distance of Saturn in our Solar System,” says Lagrange.
“We cannot yet rule out definitively, however, that the candidate companion could be a foreground or background object,” cautions co-worker Gael Chauvin. “To eliminate this very small possibility, we will need to make new observations that confirm the nature of the discovery.”
The fact that the candidate companion lies in the plane of the disc also strongly implies that it is bound to the star and its proto-planetary disc.
“Moreover, the candidate companion has exactly the mass and distance from its host star needed to explain all the disc’s properties. This is clearly another nail in the coffin of the false alarm hypothesis,” adds Lagrange. Candidate planetary systems imaged. Credit: ESO
When confirmed, this candidate companion will be the closest planet from its star ever imaged. In particular, it will be located well inside the orbits of the outer planets of the Solar System. Several other planetary candidates have indeed been imaged, but they are all located further away from their host star: if located in the Solar System, they would lie close or beyond the orbit of the farthest planet, Neptune. The formation processes of these distant planets are likely to be quite different from those in our Solar System and in Beta Pictoris.
“Direct imaging of extrasolar planets is necessary to test the various models of formation and evolution of planetary systems. But such observations are only beginning. Limited today to giant planets around young stars, they will in the future extend to the detection of cooler and older planets, with the forthcoming instruments on the VLT and on the next generation of optical telescopes,” concludes team member Daniel Rouan.
For a list of candidate exoplanets directly imaged, see this link.
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The Dawn spacecraft’s three ion engines have done their work for now, and mission engineers shut down the frugal but powerful ion propulsion system on Thursday as scheduled. The spacecraft is now gliding toward a Mars flyby/gravity assist in February 2009. “Dawn has completed the thrusting it needs to use Mars for a gravity assist to help get us to Vesta,” said Marc Rayman, Dawn’s chief engineer from JPL “Dawn will now coast in its orbit around the sun for the next half a year before we again fire up the ion propulsion system to continue our journey to the asteroid belt.” The unique propulsion system will allow Dawn to travel to the asteroid Vesta in 2011, enter orbit around the asteroid, and then leave that orbit to head to orbit another asteroid, Ceres in 2015. This has never been accomplished before, and the ion engines make it all possible.
Dawn’s ion engines are vital to the success of the misson’s 8-year, 4.9-billion-kilometer (3-billion-mile) journey to asteroid Vesta and dwarf planet Ceres. Just one of these extremely frugal powerhouses can generate more than 24 hours of thrusting while consuming about .26 kilograms (about 9 ounces) of the spacecraft’s xenon fuel supply — less than the contents of a can of soda. Over their lifetime, Dawn’s three ion propulsion engines will fire cumulatively for about 50,000 hours (over five years) — a record for spacecraft. Artists concept of Dawn. Credit: NASA/JPL
Dawn’s ion engines may get a short workout next January to provide any final orbital adjustments prior to its encounter with the Red Planet. Ions are also scheduled to fly out of the propulsion system during some systems testing in spring. But mostly, Dawn’s three ion engines will remain silent until June, when they will again speed Dawn toward its first appointment, with Vesta.
Vesta is the most geologically diverse of the large asteroids and the only known one with distinctive light and dark areas — much like the face of our Moon. Ceres is the largest body in the asteroid belt. By utilizing the same set of instruments at two separate destinations, scientists can more accurately formulate comparisons and contrasts. Dawn’s science instrument suite will measure shape, surface topography, tectonic history, elemental and mineral composition, and will seek out water-bearing minerals. In addition, the Dawn spacecraft itself and how it orbits both Vesta and Ceres will be used to measure the celestial bodies’ masses and gravity fields.
Landing sites for the Mars Science Laboratory have been narrowed down to four intriguing places on the Red Planet. The car-sized rover will have the capability to travel to more scientifically compelling sites, and with its radioisotope power source, it won’t need to rely on solar power, allowing for more flexibility in locations say project leaders at the Jet Propulsion Laboratory. After seeking input from international experts on Mars and engineers working on the landing systems, here are the four sites JPL announced (drumroll)…
Eberswalde: where an ancient river deposited a delta in a possible lake, south of Mars equator.
Gale: a crater with a mountain within that has stacked layers including clays and sulfates, near the equator. This was a favorite site for the Mars Exploration Rovers, but it was deemed to hazardous for them. Not so for MSL.
Holden: a crater containing alluvial fans, flood deposits, possible lake beds and clay-rich deposits, in the southern hemisphere.
Mawrth: , which shows exposed layers containing at least two types of clay, in the northern hemisphere, near the edge of a vast Martian highland.
“All four of these sites would be great places to use our roving laboratory to study the processes and history of early Martian environments and whether any of these environments were capable of supporting microbial life and its preservation as biosignatures,” said John Grotzinger of the California Institute of Technology, Pasadena. He is the project scientist for the Mars Science Laboratory. Wheels were put on MSL in August 2008. Image Credit: NASA/JPL-Caltech
During the past two years, multiple observations of dozens of candidate sites by NASA’s Mars Reconnaissance Orbiter have augmented data from earlier orbiters for evaluating sites’ scientific attractions and engineering risks.
JPL is assembling and testing the Mars Science Laboratory spacecraft for launch in fall 2009.
“Landing on Mars always is a risky balance between science and engineering. The safest sites are flat, but the spectacular geology is generally where there are ups and downs, such as hills and canyons. That’s why we have engineered this spacecraft to make more sites qualify as safe,” said JPL’s Michael Watkins, mission manager for the Mars Science Laboratory. “This will be the first spacecraft that can adjust its course as it descends through the Martian atmosphere, responding to variability in the atmosphere. This ability to land in much smaller areas than previous missions, plus capabilities to land at higher elevations and drive farther, allows us consider more places the scientists want to explore.”
MSL is designed to hit a target area roughly 20 kilometers (12 miles) in diameter. Also, a new “skycrane” technology to lower the rover on a tether for the final touchdown can accommodate more slope than the airbag method used for Spirit and Opportunity.
NCG 1569. Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and A. Aloisi (STScI/ESA)
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Astronomers have long wondered why a small, nearby, isolated galaxy is pumping out new stars faster than any galaxy in our local neighborhood. Usually, galaxies need some sort of gravitational interaction with other galaxies to trigger star formation, and galaxy NGC 1569 appeared to be a loner, far away from other galaxies, but churning out new stars like crazy. Now, a new look at the galaxy with the Hubble Space Telescope shows the galaxy is farther away than originally thought, which places NCG 1569 in the middle of a group of about 10 galaxies. Gravitational interactions among the group’s galaxies may be compressing gas in NGC 1569 and igniting the star-birthing frenzy.
“Now the starburst activity seen in NGC 1569 makes sense, because the galaxy is probably interacting with other galaxies in the group,” said the study’s leader, Alessandra Aloisi of the Space Telescope Science Institute in Baltimore, Md., and the European Space Agency. “Those interactions are probably fueling the star birth.”
The farther distance not only means that the galaxy is intrinsically brighter, but also that it is producing stars two times faster than first thought. The galaxy is forming stars at a rate more than 100 times higher than the rate in the Milky Way. This high star-formation rate has been almost continuous for the past 100 million years.
Discovered by William Herschel in 1788, NGC 1569 is home to three of the most massive star clusters ever discovered in the local universe. Each cluster contains more than a million stars.
“This is a prime example of the type of massive starbursts that drive the evolution of galaxies in the distant and young universe,” said team member Roeland van der Marel of the Space Telescope Science Institute. “Starburst galaxies can only be studied in detail in the nearby universe, where they are much rarer. Hubble observations of our galactic neighborhood, including this study, are helping astronomers put together a complete picture of the galaxies in our local universe. Put the puzzle pieces in the right place, as for NGC 1569, and the picture makes much more sense.”
And besides all that, it’s just a pretty picture, too!
The nebula surrounding nova V458Vul before it erupted. Credit: UCL
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The explosion of a binary star inside a planetary nebula has been detected, an event not witnessed for more than 100 years – and of course the astronomical equipment to observe such an event is much improved since a century ago. At the ends of their lives, before an all-encompassing supernova explosion, some stars undergo nova explosions, caused by nuclear reactions on their surface. Astronomers who detected the event predict that the combined mass of the two stars in the system may be high enough for the stars to eventually spiral into each other, triggering a much bigger double supernova explosion.
“The star which erupted was a nova, an event caused when matter is transferred from one star in a close binary system onto its companion, eventually triggering a runaway thermonuclear explosion,” said Roger Wesson, lead astronomer behind the discovery at University College London in England.
“In August 2007, one such exploding star was discovered in a part of the sky that had serendipitously been observed by us only a few weeks previously,” he said.
Images taken prior to the explosion (above) showed that this particular star was surrounded by a planetary nebula.
The photos were taken as part of the Isaac Newton Telescope Photometric HAlpha Survey (IPHAS), which is the first digital survey of the Milky Way in visible light and is being undertaken by an international collaboration of universities.
Now, the light flash from the explosion is passing through and illuminating the surrounding nebula, the study says. The nebula surrounding Nova V458 Vul, imaged before its central star erupted Three images showing the changes in the nebula as a result of the nova explosion, in August 2007, May 2008 and September 2008. Credit: UCL
Although several novae are discovered each year in our galaxy, only one previous nova has been seen to occur inside a planetary nebula – Nova Persei in 1901. The opportunity to watch in detail as the nova flash interacts with the nebula is a first in astronomy, said Wesson.
“The new nova, known as V458 Vulpeculae, provides an important test for models of how stars evolve,” he added. “The role of novae as potential future supernovae has thus far been difficult to analyse in detail, and so [this phenomenon] provides an opportunity to learn more about this aspect of stellar evolution.”
Possible underground glaciers on Mars. Credit: NASA
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There’s more than just a little ice under Mars’ surface. According to data from the Mars Reconnaissance Orbiter radar system, vast Martian glaciers of water ice lie buried under rocky debris. And this ice is not just at the Arctic region where the Phoenix lander scratched the surface in searching for ice. MRO found evidence for a huge amount of underground ice at much lower latitudes than any ice previously identified on the Red Planet. “Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that is not in the polar caps,” said John W. Holt of the University of Texas at Austin, who is lead author of the report. “Just one of the features we examined is three times larger than the city of Los Angeles and up to half a mile thick. And there are many more. In addition to their scientific value, they could be a source of water to support future exploration of Mars.”
Scientists say buried glaciers extend for dozens of miles from the edges of mountains or cliffs. A layer of rocky debris blanketing the ice may have preserved the underground glaciers as remnants from an ice sheet that covered middle latitudes during a past ice age. This discovery is similar to massive ice glaciers that have been detected under rocky coverings in Antarctica.
Scientists have been puzzled by what are known as aprons — gently sloping areas containing rocky deposits at the bases of taller geographical features — since NASA’s Viking orbiters first observed them on the Martian surface in the1970s. One theory has been that the aprons are flows of rocky debris lubricated by a small amount ice. Now, the shallow radar instrument on the Mars Reconnaissance Orbiter has provided scientists an answer to this Martian puzzle.
“These results are the smoking gun pointing to the presence of large amounts of water ice at these latitudes,” said Ali Safaeinili, a shallow radar instruments team member with NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The buried glaciers lie in the Hellas Basin region of Mars’ southern hemisphere. The radar also has detected similar-appearing aprons extending from cliffs in the northern hemisphere. Artists concept of a glacier on Mars. Credit: NASA
Radar echoes received by the spacecraft indicated radio waves pass through the aprons and reflect off a deeper surface below without significant loss in strength. That is expected if the apron areas are composed of thick ice under a relatively thin covering. The radar does not detect reflections from the interior of these deposits as would occur if they contained significant rock debris. The apparent velocity of radio waves passing through the apron is consistent with a composition of water ice.
“There’s an even larger volume of water ice in the northern deposits,” said JPL geologist Jeffrey J. Plaut, who will be publishing results about these deposits in the American Geophysical Union’s Geophysical Research Letters. “The fact these features are in the same latitude bands, about 35 to 60 degrees in both hemispheres, points to a climate-driven mechanism for explaining how they got there.”
The rocky debris blanket topping the glaciers apparently has protected the ice from vaporizing, which would happen if it were exposed to the atmosphere at these latitudes.
“A key question is, how did the ice get there in the first place?” said James W. Head of Brown University in Providence, R.I. “The tilt of Mars’ spin axis sometimes gets much greater than it is now. Climate modeling tells us ice sheets could cover mid-latitude regions of Mars during those high-tilt periods. The buried glaciers make sense as preserved fragments from an ice age millions of years ago. On Earth, such buried glacial ice in Antarctica preserves the record of traces of ancient organisms and past climate history.”
The ISS 10 years ago, and today. Credit: NASA, collage, N. Atkinson
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Ten years ago today the Russian built Zarya control module was launched into space and the International Space Station was born. The orbiting outpost has gone from one small module to an expansive station with ten different modules made in several different countries, a huge backbone truss structure made of 12 large pieces, and three sets of the largest solar arrays ever sent into space. The current space shuttle mission is providing the furnishings to outfit the station into a five-bedroom, two bath, two kitchen space research outpost. 164 people have visited the station in these past ten years, as the 313 ton station has circled the Earth more than 57,300 times and traveled a distance of more than 1.3 billion miles (2 billion km). See a very nifty animation of how the station was built at USA Today, see a list of all the flights so far dedicated to ISS construction, and find all the stats you’ll ever want on the ISS here.
Frequent readers of Universe Today know I have a soft spot in my heart for the ISS, and today I’d like to share some of my favorite images from the past ten years of station construction. Above is a collage of the Zarya module a decade ago, (left) and the station’s current configuration.
Koichi Wakata zooms through Zvezda. Credit: NASA
Before the station could house its first occupants, it took several missions to outfit the ISS and bring up supplies. Here, astronaut Koichi Wakata from Japan floats through the Zvezda module in October of 2000, which the STS-92 crew stocked almost completely with supplies for the first crew. Permanent occupancy began just a few weeks later when the Expedition One crew of Bill Shepherd, Yuri Gidzenko, and Sergei Krikalev opened the ISS hatch on Nov. 2, 2000.
ISS with first set of solar arrays. Credit: NASA
Shortly after the Expedition One crew arrived, the STS-97 space shuttle crew visited and installed the P6 Truss, which contains the first set of the huge solar arrays. The P6 provided enough solar power so that that soon afterward, the first laboratory could be installed. The P6 was temporarily installed on top of the Z1 Truss in December 2000.
Destiny Lab. Credit: NASA
In February of 2001 space shuttle Atlantis brought up the Destiny Laboratory. Here, the lab is in the grasp of the shuttle’s remote manipulator system (RMS) robot arm, moving it from its stowage position in the shuttle’s cargo bay and attaching it to the ISS.
Astronauts work on the P-1 Truss. Credit: NASA
The truss sections make up the “backbone” of the station. Most of the trusses are huge in themselves, some weighing 27,000 pounds. But together, they expand the station’s length to the size of a football field. Here in November 2002, Astronauts John Herrington (left) and Michael Lopez-Alegria from the STS-113 shuttle crew, work on the newly installed Port One (P1) truss. This mission activated the “railcar” on the truss, allowing astronauts to move easily up and down the truss for construction and maintenance. The station’s robotic arm (SSRMS) can also be attached to the car.
ISS in 2005. Credit: NASA
Backdropped by the blackness of space and Earth’s horizon, this full view of the International Space Station was photographed by the departing Space Shuttle Discovery crew following undocking after a construction mission in August of 2005.
Astronaut Scott Parazynski prepares to repair torn solar arrays. Credit: NASA
In an emergency operation, astronaut Scott Parazynski anchored himself to a foot restraint on the end of the Orbiter Boom Sensor System to repair a torn solar array during the STS-120 in October of 2007. Parazynski cut a snagged wire and installed homemade stabilizers designed to strengthen the damaged solar array’s structure and stability after it was torn while re-deploying the array after it was moved to its permanent position.
Columbus European module. Credit: NASA
A close-up view of the shiny new Columbus laboratory (top right), added during the STS-122 mission in February 2008, photographed by Space Shuttle Atlantis crew shortly after the undocking of the two spacecraft.
Dextre. Credit: NASA
In March of 2008, astronauts installed a large robot named Dextre outside the station. The two-armed, $200-million robot will reduce the amount of time astronauts must spend outside the space station, and could eliminate the need for up to a dozen spacewalks a year. Here’s a comparison between Dex and Hal.
STS 126 spacewalk. Credit: NASA
And finally, here’s a new image from the latest STS-126 mission. Astronauts Steve Bowen and Heidemarie Stefanyshyn-Piper (out of frame) worked to clean and lubricate part of the station’s starboard Solar Alpha Rotary Joints (SARJ) and to remove two of SARJ’s 12 trundle bearing assemblies. The spacewalkers also removed a depleted nitrogen tank from a stowage platform on the outside of the complex and moved it into Endeavour’s cargo bay. They also moved a flex hose rotary coupler from the shuttle to the station stowage platform, as well as removing some insulation blankets from the common berthing mechanism on the Kibo laboratory.
Scientists have discovered an unidentified source of high-energy cosmic rays bombarding Earth from space. They say it must be close to the solar system and it could be made of dark matter. “This is a big discovery,” says John Wefel of Louisiana State University and Principal Investigator for ATIC, Advanced Thin Ionization Calorimeter, a NASA funded balloon-borne instrument high over Antarctica. “It’s the first time we’ve seen a discrete source of accelerated cosmic rays standing out from the general galactic background.”
The new results show an unexpected surplus of cosmic ray electrons at very high energy — 300-800 billion electron volts — that must come from a previously unidentified source or from the annihilation of very exotic theoretical particles used to explain dark matter.
“This electron excess cannot be explained by the standard model of cosmic ray origin,” said Wefel. “There must be another source relatively near us that is producing these additional particles.”
According to the research, this source would need to be within about 3,000 light years of the sun. It could be an exotic object such as a pulsar, mini-quasar, supernova remnant or an intermediate mass black hole.
“Cosmic ray electrons lose energy during their journey through the galaxy,” said Jim Adams, ATIC research lead at NASA’s Marshall Space Flight Center in Huntsville, Ala. “These losses increase with the energy of the electrons. At the energies measured by our instrument, these energy losses suppress the flow of particles from distant sources, which helps nearby sources stand out.”
The scientists point out, however, that there are few such objects close to our solar system.
“These results may be the first indication of a very interesting object near our solar system waiting to be studied by other instruments,” Wefel said. ATIC high-energy electron counts. Credit: J. Chang et al.
An alternative explanation is that the surplus of high energy electrons might result from the annihilation of very exotic particles put forward to explain dark matter. In recent decades, scientists have learned that the kind of material making up the universe around us only accounts for about five percent of its mass composition. Close to 70 percent of the universe is composed of dark energy (so called because its nature is unknown). The remaining 25 percent of the mass acts gravitationally just like regular matter, but does little else, so it is normally not visible.
The nature of dark matter is not understood, but several theories that describe how gravity works at very small, quantum distances predict exotic particles that could be good dark matter candidates.
“The annihilation of these exotic particles with each other would produce normal particles such as electrons, positrons, protons and antiprotons that can be observed by scientists,” said Eun-Suk Seo, ATIC lead at the University of Maryland, College Park.
The 4,300-pound ATIC experiment is carried to an altitude of about 124,000 feet above Antarctica using a helium-filled balloon about as large as the interior of the New Orleans Superdome. The goal of the project is to study cosmic rays that otherwise would be absorbed into the atmosphere.
Researchers from ATIC published the results in the Nov. 20 issue of the journal Nature.
