Archive for May 8, 2013

NASA’s Spitzer Puts Planets In A Petri Dish

Our galaxy is teeming with a wild variety of planets. In addition to our solar system’s eight near-and-dear planets, there are more than 800 so-called exoplanets known to circle stars beyond our sun. One of the first “species” of exoplanets to be discovered is the hot Jupiters, also known as roasters. These are gas giants like Jupiters, but they orbit closely to their stars, blistering under the heat.

Thanks to NASA’s Spitzer Space Telescope, researchers are beginning to dissect this exotic class of planets, revealing raging winds and other aspects of their turbulent nature. A twist to come out of the recent research is the planets’ wide range of climates. Some are covered with a haze, while others are clear. Their temperature profiles, chemistries and densities differ as well.

“The hot Jupiters are beasts to handle. They are not fitting neatly into our models and are more diverse than we thought,” said Nikole Lewis of the Massachusetts Institute of Technology, Cambridge, lead author of a new Spitzer paper in the Astrophysical Journal examining one such hot Jupiter called HAT-P-2b. “We are just starting to put together the puzzle pieces of what’s happening with these planets, and we still don’t know what the final picture will be.”

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Birth Of A Black Hole

A new kind of cosmic flash may reveal something never seen before: the birth of a black hole.

When a massive star exhausts its fuel, it collapses under its own gravity and produces a black hole, an object so dense that not even light can escape its gravitational grip. According to a new analysis by an astrophysicist at the California Institute of Technology (Caltech), just before the black hole forms, the dying star may generate a distinct burst of light that will allow astronomers to witness the birth of a new black hole for the first time.

Tony Piro, a postdoctoral scholar at Caltech, describes this signature light burst in a paper published in the May 1 issue of the Astrophysical Journal Letters. While some dying stars that result in black holes explode as gamma-ray bursts, which are among the most energetic phenomena in the universe, those cases are rare, requiring exotic circumstances, Piro explains. “We don’t think most run-of-the-mill black holes are created that way.” In most cases, according to one hypothesis, a dying star produces a black hole without a bang or a flash: the star would seemingly vanish from the sky—an event dubbed an unnova. “You don’t see a burst,” he says. “You see a disappearance.”

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NASA’s Fermi, Swift See ‘Shockingly Bright’ Burst

Swift's X-Ray Telescope took this 0.1-second exposure of GRB 130427A at 3:50 a.m. EDT on April 27. Credit: NASA/Swift/Stefan Immler

Swift’s X-Ray Telescope took this 0.1-second exposure of GRB 130427A at 3:50 a.m. EDT on April 27. Credit: NASA/Swift/Stefan Immler

A record-setting blast of gamma rays from a dying star in a distant galaxy has wowed astronomers around the world. The eruption, which is classified as a gamma-ray burst, or GRB, and designated GRB 130427A, produced the highest-energy light ever detected from such an event.

“We have waited a long time for a gamma-ray burst this shockingly, eye-wateringly bright,” said Julie McEnery, project scientist for the Fermi Gamma-ray Space Telescope at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The GRB lasted so long that a record number of telescopes on the ground were able to catch it while space-based observations were still ongoing.”

Fermi’s Large Area Telescope (LAT) recorded one gamma ray with an energy of at least 94 billion electron volts (GeV), or some 35 billion times the energy of visible light, and about three times greater than the LAT’s previous record. The GeV emission from the burst lasted for hours, and it remained detectable by the LAT for the better part of a day, setting a new record for the longest gamma-ray emission from a GRB.

The burst subsequently was detected in optical, infrared and radio wavelengths by ground-based observatories, based on the rapid accurate position from Swift. Astronomers quickly learned that the GRB was located about 3.6 billion light-years away, which for these events is relatively close.

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Quest For Dark Matter Begins With A Few Tiny Bubbles

Northwestern University physicist Eric Dahl is part of a group of physicists that has just launched an unusual new experiment in an attempt to be the first to directly confirm the existence of dark matter.

Scientists this week heard their first pops in an experiment that searches for signs of dark matter in the form of tiny bubbles. The experiment’s one-of-a-kind detector is located in a laboratory a mile and a half underground in Sudbury, Ontario.

“For every gram of light matter, or atoms, in the universe, there are 5.5 grams of dark matter,” said Dahl, an assistant professor of physics and astronomy in the Weinberg College of Arts and Sciences. “It is still unknown what this dark matter is actually made of, but whatever it is, it’s something new. Physicists already have ruled out every known particle.

“If we do find dark matter, not only will we answer one of the biggest mysteries in cosmology and astrophysics, we’ll be seeing into a new world of particle physics as well,” he said. “The potential payoff is huge.”

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