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Dark Matter in the Life of Dead Galaxies

An image of the centre of the Coma Cluster. Green dots show the distribution of thousands of faint dwarf galaxies, which do not include the recent discoveries of large, ultra-diffuse galaxies. In this crowded region of space, galaxies will frequently interact gravitationally with one another and the underlying dark matter of the cluster itself. Credit: NASA/JPL-Caltech/GSFC/SDSS

An image of the centre of the Coma Cluster. Green dots show the distribution of thousands of faint dwarf galaxies, which do not include the recent discoveries of large, ultra-diffuse galaxies. In this crowded region of space, galaxies will frequently interact gravitationally with one another and the underlying dark matter of the cluster itself. Credit: NASA/JPL-Caltech/GSFC/SDSS

By Cameron Yozin

A recent discovery in the Coma Cluster highlights the important role of dark matter in transforming galaxies.

The full text of this article can be purchased from Informit.

The billions of galaxies that make up the known universe come in a dazzling array of masses, shapes and colours. In the past few decades we’ve made incredible advances when it comes to observing these galaxies and better understanding how such diversity arose in the universe, yet our observations continue to surprise us.

To understand why galaxies look different, consider the fact that people, born in different parts of the world and going about their individual lives while interacting with different people, look different. Similarly, we find that the appearance of galaxies, ranging from the smallest with only a few thousand stars to the largest with more than a trillion times the mass of our Sun, are a product of the environment in which they form and the interactions they then have with other galaxies.

While people have some choice over the direction their lives take, the fate of galaxies is controlled by the all-permeating force of gravitational attraction. In many cases, this causes them to collide in spectacular fashion, leading to the formation of yet more massive galaxies. In other cases, a galaxy may be drawn towards the combined gravity of many other galaxies lying in a single gravitationally-bound structure known as a galaxy cluster.

Transforming Galaxies

The Coma Cluster,which lies 300 million light years from us, is a relatively...

The full text of this article can be purchased from Informit.