For My Daughter: Milky Way Galaxy As Seen from Earth II

For My Daughter: Milky Way Galaxy As Seen from Earth

Two Parts of the Milky Way Galaxy Rotate Differently

Huge Newfound Part of Milky Way Rotates Backward
By Robert Roy Britt
Senior Science Writer

Our Milky Way Galaxy has two distinct parts in its outer reaches that rotate in opposite directions, astronomers announced today.

The galaxy has a bulbous core where stars are tightly packed and orbiting rather furiously around the central black hole. Then there's the big flat disk with its spiral arms, also orbiting the galactic center somewhat in the manner of a hurricane's spiral bands. We live on one of those arms. Around it all is a halo of stars that don't all behave in such an orderly fashion. That much researchers knew.

Now they find the halo has two parts.

"By examining the motions and chemical makeup of the stars, we can see that the inner and outer halos are quite different beasts and they probably formed in different ways at different times," said Daniela Carollo, a researcher at Italy's Torino Observatory and the Australian National University.

The finding, detailed in the Dec. 12 issue of the journal Nature, is based on 20,000 stars observed as part of the Sloan Digital Sky Survey.

Intelligent Life in Our Galaxy? Alan Bellows

When consulting the wisdom of probability, one finds that the universe ought to be teeming with technology-toting aliens; but aside from a couple of interesting-but-inconclusive detections, no discernibly intelligent patterns have ever been observed by Earth's space-listening instruments. One might surmise that the conspicuous silence is "evidence of absence," but such a conclusion might be a bit premature under the circumstances.