Where We Fit in our Galaxy

(Photo Credit: Hubblesite.org)

Our Milky Way lays nearly parallel to the horizon this month, so where do we reside in our galaxy? Earth is in the galactic backwaters, in other words ‘way out there’, but let’s fully explore the scale. Our galaxy is 100,000 light years across and 33,000 light years thick. If we tried to count all the stars we might have almost 300 billion stars, but it’s very difficult to get an accurate count, because of the shear size of the galaxy.  Galaxies can collide, merge or cannibalize other galaxies potentially taking on more stars or more mass. This results in stars that are not native to our galaxy, however we know the sun is one of the original members. Explore this expansive topic with Dave and Derrick on this Week’s Sky Talk.

[audio: st20110516.mp3]