Saturday, January 10, 2009

Spinning in Space

Milky way 'larger than imagined'
A recent disclosure indicates that the Milky Way is considerably larger (contains more heavenly bodies), bulkier (more mass) and spinning faster (its all relative) than astronomers thought.

For decades, astronomers and stargazers thought that the Milky Way, was a weakling runt compared to the larger Andromeda, but not anymore.

Scientists mapped the Milky Way in a more detailed, three-dimensional way and found that it is 15% greater breadth. More important, it is significantly more dense, with 50% additional mass, which is similar to the weight but includes a size factor.

The new findings were presented at the American Astronomical Society's convention in Long Beach, California. Mark Reid of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts, said it was the cosmic equivalent of him suddenly increasing his bulk from his 5ft 5in, 10 stone frame, to 6ft 3in and 15 stone.

"Previously we thought Andromeda was dominant over the Milky Way, and that we were the little sibling of Andromeda," Mr Reid said. "But now it's more like we're sibling twins."

The fact that the Milky Way and Andromeda are of similar mass means that they share a similar attraction to each other, not necessarily good news. A more massive and attractive Milky Way means that it could be heading for a more violent collision with the neighbouring Andromeda galaxy, sooner than predicted. This event is still likely to be billions of years from now.

Mr Reid and his colleagues used a large system of 10 radio telescope antennas to measure the brightest newborn stars in the galaxy at different times in Earth's orbit around the sun. They made a map of those stars, not just in the locations where they were first seen, but in the third dimension of time - something Mr Reid said has not been done before.

Using this approach, Mr Reid was able to determine the speed at which the spiral-shaped Milky Way is spinning around its centre. That speed - about 568,000mph - is faster than the 492,000mph that scientists had been using for decades.

So now you know why you were feeling a bit dizzy after the New Year Celebrations

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