Nature vs. Nurture
Social scientists still debate why people turn out the way they do -- is it nature, is it nurture, or is it a combination of the two? Space scientists wonder the same thing about galaxies. How much of a galaxy's fate is determined by the circumstances of its birth, and how much depends on its later interactions with the rest of the universe?
To find out, astronomers study lots of galaxies. Some of them are members of clusters, while others travel through the universe alone.
One of the clusters is known as the Coma Cluster. It's 300 million light-years away, and it contains thousands of galaxies.
One reason to study the Coma Cluster is that the demographics of galaxies are different in clusters from those in what astronomers call the "field" -- the spaces between clusters.
In the field, for example, there are lots of spiral galaxies, which are giving birth to new stars. But there are few spirals in clusters. Instead, there are lots of galaxies that are shaped like disks, as spirals are, but that don't have the bright young stars that outline spiral arms. That may be because the environment in a cluster strips away the gas that forms stars, so spirals quickly lose their spiral arms.
A team of astronomers is studying the reasons behind the different galaxy populations by using a large survey of the Coma Cluster conducted with Hubble Space Telescope. The observations could shed light on the question of galactic nature versus nurture.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.