Looking Up: One Star, Two star... Red Star, Blue Star...

May 15, 2017

Laniakea - galactic clusters galore
Credit Wikipedia

This week on Looking Up Hal gives some perspective on the amount of stars in the sky.  

One of the challenges in astronomy is getting your brain around some of the really big numbers involved in studying the night sky. Our own galaxy, the Milky Way, contains between 200 and 300 billion stars. That huge number may be easier to visualize when I tell you there are more stars in the Milky Way than there are grains of sand on all the beaches and deserts on Earth. 

And there are more galaxies blanketing the night sky, each of them with more stars than grains of sand, than there are grains of sand. So, that’s a lot of stars!

Some of these galaxies appear bunched together in the Southern Colorado sky, in the constellation of Virgo, in a group of perhaps 2000 galaxies known as the Virgo Cluster! This cluster is, in turn, part of the Virgo Super Cluster. The Super Cluster, spanning roughly 110 million light years, contains at least 100 other clusters of galaxies. Sounds pretty big, doesn’t it? Well, the Virgo Super Cluster is only one of at least 10 million super clusters known to exist in the Universe! And it’s only one small lobe of an even bigger group of super clusters, named Laniakea! So how many galaxies are in Laniakea? Over 100,000, with our own Milky Way just one of that number. And on a clear Spring evening, you can take a look through a telescope and see a number of our neighbor galaxies, just by taking a visual tour of the constellation Virgo. And next time you are on a beach or a dessert; don’t forget to count the grains of sand! The universe is a big place!

If you’d like to take a closer look at the Virgo Cluster or any of the wonderful and amazing things in the sky, please visit CSASTRO.org for a link to information on our monthly meetings and our free public star parties! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!