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Archive for the 'Astronomy' Category

Starburst Galaxy NGC 908

July 28th, 2006 by admin

Galaxy NGC 908. Image credit: ESOClick to enlarge
This photograph of galaxy NGC 908 was taken with the European Southern Observatory’s Very Large Telescope. This spiral galaxy was first discovered in 1786 by William Herschel, and is considered a starburst galaxy. Clusters of young, massive stars pepper its spiral arms indicating regions of furious star formation. NGC 908 must have had a recent encounter with another galaxy; the gravitational interaction between the galaxies caused gas clouds to collapse, igniting star formation.

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New View on Pulsars

July 27th, 2006 by admin

Artist impression of a pulsar’s magnetosphere. Image credit: W.Becker/MPIClick to enlarge
Pulsars are the rapidly spinning corpses of massive stars. And although they were discovered nearly 40 years ago, they still hold many mysteries. One such mystery: why do pulsars have million-degree hotspots around their poles? New data from ESA’s XMM-Newton X-Ray observatory have cast doubt on the theory that charged particles are colliding with the pulsar’s surface at its poles. XMM-Newton failed to see the X-ray emissions in several old pulsars that should have been very bright if particles were continuously colliding.

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A New View of Quasars

July 26th, 2006 by admin

Artist illustration of a quasar. Image credit: CfAClick to enlarge
Some of the brightest objects in the Universe are quasars. A mystery for decades, most astronomers now believe quasars are the bright centres of galaxies with actively feeding supermassive black holes. A team of researchers have found evidence that there might be something very different at the heart of these galaxies to cause quasars. Instead of black holes consuming matter, there could be objects with powerful magnetic fields that act like propellers, churning matter back into the galaxy.

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Podcast: Inevitable Supernova

July 25th, 2006 by admin

Artist impression of RS Ophiuchi. Image credit: CfAClick to enlarge
Consider the dramatic binary system of RS Ophiuchi. A tiny white dwarf star, about the size of our Earth, is locked in orbit with a red giant star. A stream of material is flowing from the red giant to the white dwarf. Every 20 years or so, the accumulated material erupts as a nova explosion, brightening the star temporarily. But this is just a precursor to the inevitable cataclysm – when the white dwarf collapses under this stolen mass, and then explodes as a supernova. Dr. Jennifer Sokoloski has been studying RS Ophiuchi since it flared up earlier this year; she discusses what they’ve learned so far, and what’s to come.

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Planetary Disks Slow Stellar Rotation

July 25th, 2006 by admin

Artist illustration of a planetary disk. Image credit: NASA/JPL/SpitzerClick to enlarge
New data from NASA’s Spitzer Space Telescope are giving astronomers a sense of how protoplanetary disks might act as a brake to slow stellar rotation. Young stars spin very quickly, often completing a rotation in less than a day. They could spin even faster, but something is slowing them down. Spitzer gathered data on 500 young stars in the Orion Nebula. The fastest spinning stars don’t have planetary disks around then. It might be that the magnetic field of the star interacts with the planetary disk, slowing the star down.

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A Glimpse at the Future of Our Sun

July 21st, 2006 by admin

Ring nebula. Image credit: Goodrich/Bolte/W. M. KeckClick to enlarge
A team of astronomers recently used Arizona’s Infrared-Optical Telescope Array (IOTA) of three linked telescopes to peer 4 billion years into the future, when our Sun balloons up to become a red giant star. The three instruments act as a powerful interferometer, providing a view that would only be possible with a much larger instrument. They observed several red giant stars – the eventual fate of our Sun – and discovered their surfaces to be mottled and varied, covered with enormous sunspots.

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