Hubble telescope has just produced this brain-expanding image of Galaxy Cluster Abell 1689, a dense thicket of galaxies and globular clusters 2.25 billion light years away. It's also a region of the universe that's rich in dark matter.
Here's the full deep field image. Just look at all those freakin galaxies! Nearly every single one of those blobs, swirls, and spirals is a galaxy that's like our own Milky Way. You can even see some barred spirals, which gives you a good idea of what the Milky Way might look like from a distance.
Astronomers now believe that galaxies tend to cluster together because of the structure of dark matter in the universe. This matter tends to form webs, long strands of invisible matter that meet in dense nodes. At these nodes, the dark matter emits enough gravity that it causes galaxies to be born in clusters.
One of the most fascinating aspects of Abell 1689 isn't the number of galaxies, though. It's the number of globular clusters. These are massive clusters of millions of ancient stars that orbit galaxies, and in Abell 1689 there are 160,000 of them. (As a point of comparison, the Milky Way has about 150.) These clusters may be over 10 billion years old, and were probably thrown off when the galaxies in this cluster were forming. They are also nests of dark matter.
The research team found that the globular clusters are intimately intertwined with dark matter. "In our study of Abell 1689, we show how the relationship between globular clusters and dark matter depends on the distance from the galaxy cluster's center," explained team member Karla Alamo-Martinez of the Center for Radio Astronomy and Astrophysics of the National Autonomous University of Mexico in Morelia. "In other words, if you know how many globular clusters are within a certain distance, we can give you an estimate of the amount of dark matter."
Below, you can see highlighted some of these globular clusters.
According to NASA:
The image at left, taken by Hubble's Advanced Camera for Surveys, shows the numerous galaxies that make up Abell 1689. The box near the center outlines one of the regions sampled by Hubble, containing a rich collection of globular clusters.
The monochromatic view at right, taken at visible wavelengths, zooms into the region packed with globular clusters. They appear as thousands of tiny white dots, which look like a blizzard of snowflakes. The larger white blobs are entire galaxies of stars.
Find out more on the Hubble Telescope site.