Archive for May, 2013

NASA’s WISE Mission Finds Lost Asteroid Family Members

Data from NASA’s Wide-field Infrared Survey Explorer (WISE) have led to a new and improved family tree for asteroids in the main belt between Mars and Jupiter.

Astronomers used millions of infrared snapshots from the asteroid-hunting portion of the WISE all-sky survey, called NEOWISE, to identify 28 new asteroid families. The snapshots also helped place thousands of previously hidden and uncategorized asteroids into families for the first time. The findings are a critical step in understanding the origins of asteroid families, and the collisions thought to have created these rocky clans.

“NEOWISE has given us the data for a much more detailed look at the evolution of asteroids throughout the solar system,” said Lindley Johnson, the program executive for the Near-Earth Object Observation Program at NASA Headquarters in Washington. “This will help us trace the NEOs back to their sources and understand how some of them have migrated to orbits hazardous to the Earth.”

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New ET Detection Method Leads To Quest For World’s Largest Telescope

Until recently, one of the ultimate mysteries of the universe — how many civilizations may exist on planets orbiting other stars in the Milky Way Galaxy — relied on the possibility of detecting intelligent beings by radio signals. Now a team of astronomers, engineers, and physicists from the University of Hawaii, the University of Freiburg, and elsewhere has proposed a new and powerful technique to search for intelligent life.

The revolutionary method is described by four of the team’s astronomers in the June 2013 issue of Astronomy magazine, the world’s largest magazine on the subject, with a print and web readership of half a million each month. The story, “How to Find ET with Infrared Light,” was written by Jeff R. Kuhn of the University of Hawaii’s Institute for Astronomy, Svetlana V. Berdyugina of the University of Freiburg and the Kiepenheuer Institute for Solar Physics in Germany, David Halliday of Dynamic Structures, Ltd., in British Columbia, and Caisey Harlingten of the Searchlight Observatory Network in The Grange, Norwich, England.

Rather than looking for radio waves, the team suggests searching for the heat signatures of nearby planets, which requires a giant telescope that could detect infrared radiation directly from an exoplanet, thus revealing the presence of a civilization.

“The energy footprint of life and civilization appears as infrared heat radiation,” says Kuhn, the project’s lead scientist. “A convenient way to describe the strength of this signal is in terms of total stellar power that is incident on the host planet.” The technique arises from the fact that a civilization produces power that adds to the heat on a planet, beyond the heat received from its host star. A large enough telescope, idealized for infrared detection, could survey planets orbiting stars within 60 light-years of the Sun to see whether or not they host civilizations.

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Herschel Space Observatory Finds Galaxy Mega Merger

Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

A massive and rare merging of two galaxies has been spotted in images taken by the Herschel space observatory, a European Space Agency mission with important NASA participation.

Follow-up studies by several telescopes on the ground and in space, including NASA’s Hubble Space Telescope and Spitzer Space Telescope, tell a tale of two faraway galaxies intertwined and furiously making stars. Eventually, the duo will settle down to form one super-giant elliptical galaxy.

The findings help explain a mystery in astronomy. Back when our universe was 3 billion to 4 billion years old, it was populated with large reddish elliptical-shaped galaxies made up of old stars. Scientists have wondered whether those galaxies built up slowly over time through the acquisitions of smaller galaxies, or formed more rapidly through powerful collisions between two large galaxies.

The new findings suggest massive mergers are responsible for the giant elliptical galaxies.

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NASA Hosts News And Social Media Events Around This Week’s Asteroid Pass

NASA is inviting members of the media and public to participate in online and television events May 30-31 with NASA officials and experts discussing the agency’s asteroid initiative and the Earth flyby of the 1.7-mile-long asteroid 1998 QE2.

At 4:59 p.m. EDT, Friday, May 31, 1998 QE2 will pass by Earth at a safe distance of about 3.6 million miles — its closest approach for at least the next two centuries. The asteroid was discovered Aug. 19, 1998, by the Massachusetts Institute of Technology’s Lincoln Near Earth Asteroid Research Program near Socorro, N.M.

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NASA’s Swift Reveals New Phenomenon In A Neutron Star

Credit: ESA/XMM-Newton/M. Sasaki et al

Credit: ESA/XMM-Newton/M. Sasaki et al

Astronomers using NASA’s Swift X-ray Telescope have observed a spinning neutron star suddenly slowing down, yielding clues they can use to understand these extremely dense objects.

A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. A neutron star can spin as fast as 43,000 times per minute and boast a magnetic field a trillion times stronger than Earth’s. Matter within a neutron star is so dense a teaspoonful would weigh about a billion tons on Earth.

This neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses.

Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar’s rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate.

“Astronomers have witnessed hundreds of events, called glitches, associated with sudden increases in the spin of neutron stars, but this sudden spin-down caught us off guard,” said Victoria Kaspi, a professor of physics at McGill University in Montreal. She leads a team that uses Swift to monitor magnetars routinely.

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Researchers Explain Magnetic Field Misbehavior In Solar Flares: The Culprit Is Turbulence

May 28, 2013 2 comments

Credit: NASA/SDO

Credit: NASA/SDO

When a solar flare filled with charged particles erupts from the sun, its magnetic fields sometime break a widely accepted rule of physics. The flux-freezing theorem dictates that the magnetic lines of force should flow away in lock-step with the particles, whole and unbroken. Instead, the lines sometimes break apart and quickly reconnect in a way that has mystified astrophysicists.

But in a paper published in the May 23 issue of the journal Nature, an interdisciplinary research team led by a Johns Hopkins mathematical physicist says it has found a key to the mystery. The culprit, the group proposed, is turbulence—the same sort of violent disorder that can jostle a passenger jet when it occurs in the atmosphere. Using complex computer modeling to mimic what happens to magnetic fields when they encounter turbulence within a solar flare, the researchers built their case, explaining why the usual rule did not apply.

“The flux-freezing theorem often explains things beautifully,” said Gregory Eyink, a Department of Applied Mathematics and Statistics professor who was lead author of the Nature study. “But in other instances, it fails miserably. We wanted to figure out why this failure occurs.”

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A Hidden Population Of Exotic Neutron Stars

May 28, 2013 2 comments

When a massive star runs out of fuel, its core collapses to form a neutron star, an ultradense object about 10 to 15 miles wide. The gravitational energy released in this process blows the outer layers away in a supernova explosion and leaves the neutron star behind.

Most neutron stars are spinning rapidly – a few times a second – but a small fraction have a relatively low spin rate of once every few seconds, while generating occasional large blasts of X-rays. Because the only plausible source for the energy emitted in these outbursts is the magnetic energy stored in the star, these objects are called “magnetars.”

Most magnetars have extremely high magnetic fields on their surface that are ten to a thousand times stronger than for the average neutron star. New observations show that the magnetar known as SGR 0418+5729 (SGR 0418 for short) doesn’t fit that pattern. It has a surface magnetic field similar to that of mainstream neutron stars.

“We have found that SGR 0418 has a much lower surface magnetic field than any other magnetar,” said Nanda Rea of the Institute of Space Science in Barcelona, Spain. “This has important consequences for how we think neutron stars evolve in time, and for our understanding of supernova explosions.”

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