Wednesday, May 30, 2007

spiral galaxy

the hubbles space telescope captures yet another fantastic image!

this beautiful spiral galaxy sits in the northern constellation Ursa Major, and can be viewed with some detail through binoculars. it is one of the brightest galaxies in earth's sky and was originally discovered by Johann Elert Bode in 1774 who described it as a "nebulous patch." the light from this galaxy takes 12 million light years to reach us! as far as i know, this galaxy doesnt have a creative normal name, but astronomers refer to it mostly as M81 (messier object 81) or sometimes as NGC 3031.

the above image was taken with light that is visible to our eyes. the center of the galaxy looks like a bright fuzz ball where lots of gas and so many stars swirl around the center that we cannot make out individual stars among the masses even with hubble's resolution! towards the outside of M81 the gas and stars are clumped together in long swirling arms that give this galaxy type the name "spiral". the light in the outer arms looks bluer than the yellow light near the center mostly because the stars are younger. you can see darks patches throughout the galaxy which loosely line up with the spiral arms and then show more intricate patterns on smaller scales. these are patches of "dust"... thicker molecules that block us from seeing the light given off by the stars behind them... harbor nurseries for new stars. gas in galaxies recycles over and over unless it gets locked into a small star that lives longer than the age of our universe so far.....

cool stuff. thanks apod and hst.

1 comment:

Philip. said...

That photo is just so impressive!