At the Cosmic Table with Giants

When you go out and look up at the night sky, you see stars and planets. If you’re lucky, you might get to see the Milky Way. That’s our galaxy — and we see it from the inside. When you first start to learn about astronomy, the Milky Way probably seems like the biggest thing you can imagine. It has hundreds of billions of stars, countless planets, and at least one place where life exists (here on Earth). If you wanted to travel across the galaxy, it would take a few hundred thousand years at the speed of light, and much more time at slower speeds. We’re not traveling at Star Trek-style speeds yet.

Imagine going out beyond the Milky Way. What would you find?  Well, for one thing, you’d find other galaxies. The closest ones are the Magellanic Clouds (at about 170,000 light-years away), the Andromeda Galaxy (at a distance of 2.5 (or so) million light-years away), and beyond that, a slew of others that make up what’s called the “Local Group” of galaxies. The whole group occupies a region of space about 3 million light-years across.

Beyond them are more galaxies, some large, some small. Astronomers have been studying distant but “local” galaxies, and have found some interesting things about our neighborhood. Within 20 million light-years, galaxies are organized into what they call a “Local Sheet” that stretches out about 35 million light-years.  Arranged in this sheet is a group of twelve very large galaxies that act somewhat like a circular fence around our region of space. The astronomers mapping this region of space call these galaxies the “Council of Giants”.

They’re an interesting bunch of galaxies. There are elliptical giants, and of course the Andromeda and Milky Way galaxies are spirals. The spin directions of these “Council” members go around a small circle in the sky, which should  tell astronomers something about the interactions of these galaxies in the distant past.

This is an interesting 3D view of our local neighborhood that will help astronomers figure out the arrangement of matter in the larger universe. And, how those arrangements came to be. The origin and evolution of the universe (a science called cosmology) is largely focused on how the galaxies formed — and how they came to be arrayed in the giant sheets and filaments of matter that dominate the arrangement of matter in the universe. Want to know more about this interesting peek at our local galactic neighborhood?  Check out the story here, at the Royal Astronomical Society’s web page.