Science & TechnologyS


Telescope

Cosmic surprise: Many asteroids are comets


Agence France-Presse
Thu, 16 Jul 2009 05:45 UTC
meteor streaking across the sky
© AFP/NASA-HO/FileThis November 2000 NASA file image shows a meteor streaking across the sky during the Leonid meteor shower. Many of the primitive bodies wandering the asteroid belt between Mars and Jupiter are former comets, tossed out of orbit by a brutal ballet between the giant outer planets, say a team of astrophysicists.
Many of the primitive bodies wandering the asteroid belt between Mars and Jupiter are former comets, tossed out of orbit by a brutal ballet between the giant outer planets, say a team of astrophysicists.

A commonly accepted theory is that the asteroid belt is the rubble left over from a "proto-planetary disk," the dense ring of gas that surrounds a new-born star.

But the orbiting rocks have long been a source of deep curiosity. They are remarkably varied, ranging from mixtures of ice and rock to igneous rocks, which implies they have jumbled origins.

The answer to the mystery, according to a study published by the British journal Nature on Wednesday, is that a "significant fraction" of the asteroid population in fact comprises ex-comets.

Famously described as "dirty snowballs" of ice and dust, comets are lonely, long-distance wanderers of the Solar System whose elliptical swing around the Sun can take decades.

Researchers in France and the United States ran a mathematical model of the development of the early Solar System, when the planets were accreting from clustering masses of dust and gas.
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Saturn

Pluto's kin may have invaded asteroid belt

Rachel Courtland
New Scientist
Wed, 15 Jul 2009 04:28 UTC
Millions of objects in the solar system's main asteroid belt may be icy interlopers from beyond Neptune that were flung into their present orbits after a violent migration of the giant planets, a new simulation suggests.

asteroid belt
© NASA/JPL-CaltechAbout 20 per cent of the objects in the main asteroid belt may have gotten their start beyond Neptune, a new simulation suggests
The solar system's main asteroid belt is a diverse mix of objects that orbit between Mars and Jupiter. These asteroids are generally thought to have formed close to their present locations, so their compositions should reflect the original distribution of gas and dust that surrounded the sun there and eventually condensed into solid bodies.

"People have just been assuming that what we see there, formed there," says Hal Levison of the Southwest Research Institute in Boulder, Colorado.

But Levison and others suspect some 20 per cent of the asteroids in the belt may be comet-like objects that were born in colder climes, beyond the orbit of Neptune.
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People

Facebook hits a quarter billion users

Caroline McCarthy
CNET News
Wed, 15 Jul 2009 00:38 UTC
Least surprising news of the day: Facebook has officially grown to 250 million active users across the world, according to a post on the company blog by CEO Mark Zuckerberg.

"For us, growing to 250 million users isn't just an impressive number; it is a mark of how many personal connections all of you have made, and how far we at Facebook have to go to extend the power of connection to the billions of people around the world," Zuckerberg wrote. (The post is accompanied by an animation of how Facebook's growth spread around the world, which is pretty cool.)
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Info

Blind can take wheel with vehicle designed by university engineering design team

Steven Mackay
Virginia Tech
Wed, 15 Jul 2009 23:12 UTC
Image
© Steven Mackay, Virginia TecWesley Majerus, an access technology specialist with the National Federation of the Blind's Jernigan Institute, finishes driving the Virginia Tech Blind Driver Challenge vehicle around a roped-off driving course on a campus parking lot. The experience, he said, was liberating.
Blacksburg, Va. -- A student team in the Virginia Tech College of Engineering is providing the blind with an opportunity many never thought possible: The opportunity to drive.

A retrofitted four-wheel dirt buggy developed by the Blind Driver Challenge team (http://www.me.vt.edu/blinddriver/) from Virginia Tech's Robotics and Mechanisms Laboratory uses laser range finders, an instant voice command interface and a host of other innovative, cutting-edge technology to guide blind drivers as they steer, brake, and accelerate. Although in the early testing stage, the National Federation of the Blind -- which spurred the project -- considers the vehicle a major breakthrough for independent living of the visually impaired.
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Attention

Noctilucent Clouds Go Wild


Space Weather
Wed, 15 Jul 2009 20:39 UTC
Image
© Olivier Lagrave
In France, yesterday was Bastille Day, and the heavens themselves joined the party. "As we celebrated the storming of the Bastille on July 14th, noctilucent clouds (NLCs) stormed the sky of Paris!" reports Olivier Lagrave who photographed the Eiffel Tower framed in electric blue.

"The display was so breathtaking (my first actually) that I almost forgot to watch the fireworks," he says.

Noctilucent clouds are seldom seen as far south as France--not to mention seen through fireworks. But the display wasn't over when Bastille Day ended. By sunrise on July 15th, the mysterious clouds had invaded the United States. Mike Hollingshead sends this photo from Blair, Nebraska.
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Satellite

Venus probe images hint at ancient ocean


CBC News
Tue, 14 Jul 2009 14:13 UTC
Long before Venus became a hot, dry and barren planet with a choking mass of carbon dioxide for an atmosphere, it might have once been home to shifting continents and an ocean of water, according to the latest data from a European space probe.

Using infrared images of the planet's southern hemisphere taken in 2006 and 2007 from the Venus Express probe, German astronomers say they have produced a map that reveals the planet's highland plateaus were likely once ancient continents surrounded by water.
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Info

NASA Sees Carlos Power Back Up To Hurricane Status In 3D

Rob Gutro
Space Daily
Wed, 15 Jul 2009 02:36 UTC
Image
© NASA/SSAI, Hal PierceTRMM 3-D image shows thunderstorm tops reaching about 9.3 miles high in the eastern side of the storm.
Carlos became a hurricane for about 24 hours over the previous weekend, then powered down to a tropical storm and now atmospheric conditions have enabled him to power back into a hurricane in the Eastern Pacific Ocean.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite has been capturing images of Carlos since it was born as tropical depression #4E last week. Scientists at NASA can use TRMM data to provide forecasters a 3-D look at the storm's cloud heights and rainfall, which is extremely helpful in forecasting.

"One of the interesting capabilities of the TRMM satellite is its ability to see through clouds with its Precipitation Radar (PR) and reveal the 3-D structure within storms such as Hurricane Carlos," said Hal Pierce, on the TRMM mission team in the Mesoscale Atmospheric Processes Branch at NASA's Goddard Space Flight Center, Greenbelt, Md.
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Telescope

NASA's Fermi Finds Gamma-ray Galaxy Surprises

Francis Reddy
NASA
Wed, 15 Jul 2009 00:15 UTC
Image
© ESA/NASA/AVO/Paolo PadovaniThis artist's concept shows the core of an active galaxy, where a feeding supermassive black hole drives oppositely directed particle jets.
Back in June 1991, just before the launch of NASA's Compton Gamma-Ray Observatory, astronomers knew of gamma rays from exactly one galaxy beyond our own. To their surprise and delight, the satellite captured similar emissions from dozens of other galaxies. Now its successor, the Fermi Gamma-ray Space Telescope, is filling in the picture with new finds of its own.

"Compton showed us that two classes of active galaxies emitted gamma rays -- blazars and radio galaxies," said Luigi Foschini at Brera Observatory of the National Institute for Astrophysics in Merate, Italy. "With Fermi, we've found a third -- and opened a new window in the field."
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Question

Another cosmic-ray puzzle: Are iron nuclei bombarding Earth?

Rachel Carr
Symmetry Breaking
Mon, 13 Jul 2009 19:41 UTC
auger-fluorescence-telescope
© UnknownOne of the four fluorescence telescopes of the Pierre Auger Observatory. They monitor the atmosphere above the water tanks for light emitted by cosmic-ray showers.
For decades, scientists have thought that the highest-energy cosmic rays - those packing up to a million trillion electronvolts - were almost exclusively protons. But data from the Pierre Auger Observatory in Argentina, the world's top facility dedicated to ultra-high-energy cosmic rays, could tell a startlingly different story. At the International Cosmic Ray Conference, held from July 7 to 15 in Lodz, Poland, Auger scientists are presenting data that raises the possibility that some of those super-speedy cosmic bullets could actually be iron nuclei.

"It would surprise a lot of people if some of these particles turned out to be iron," says Hank Glass, an Auger collaborator at Fermi National Accelerator Laboratory. While scientists can imagine mechanisms that would accelerate protons up to nearly the speed of light, they have no idea where ultra-energetic iron nuclei could originate.
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Info

Lab Breaks Own Record With Creation of Strongest Dipole Magnet

Kelsey Demmon
The Daily Californian
Mon, 06 Jul 2009 08:19 UTC
Lawrence Berkeley National Laboratory has broken a world record for the world's strongest magnet. Scientists and engineers at the lab have created a dipole magnet with the field strength of 14.7 tesla, which is more than 300,000 times the strength of the earth's magnetic pull.

The lab also held the previous record, set in 1997, for the world's strongest magnet. The previous magnet had a field strength of only 13.5 tesla.

About 20 scientists worked together in a Superconducting Magnet Group to create this new superconducting magnet. A new, simpler design was used to replace the complex coil design that had been the normal protocol.
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