- from Galaxies
Orbiting around the center of the Milky Way is like being on a never-ending merry-go-round. Our view of the universe constantly changes—but extremely slowly! One complete circle takes 225 million years. The last time Earth was in its present position in our galaxy, the age of dinosaurs had just begun!
From our spot on the galactic merry-go-round, we cannot see the entire galaxy. We estimate its shape by using what we can see and by comparing it to other galaxies. From a bird’s-eye view, the Milky Way probably looks like a barred spiral—spiral arms that spin out from a central bar. From the side, the Milky Way looks like the edge of a flat plate. A spherical halo of stars bulges above and below the center of the plate. We can’t see the nucleus (core) of our galaxy. Stars, gas clouds, dust rings, and star clusters block our view. There’s much, much more to the Milky Way than meets the naked eye.