Hey I love your blog and mind boggling photos of our universe. Could you please explain what The Great Attractor is?
The Great Attractor is less of an object and more of a region in super-galactic space. It is located very close to the Hydra-Centaurus galaxy super-cluster (which is a cluster of clusters of galaxies) and close to our own Virgo super-cluster (This is the cluster of galaxy clusters that our milky way is in). This map places us in a cosmic scale with our neighboring super-clusters, each dot is one or more galaxies:
In the above image the red areas represent areas of relatively high gravitational attraction and the purple areas represent areas of relatively low gravitational attraction. The Great Attractor has been observed to be tens of thousands of times more massive than our own galaxy and all of its mass is densely packed into a small amount of space. It is currently pulling all of the galactic super-clusters in its area toward it. The Great Attractor is not understood very well because we suspect that its secrets are hidden in “dark matter” and we have no direct view of it. It is obscured by our own Milky Way:
The blue portions of this above map represent areas of highly dense mass. Notice that this gives us little “direct” information about the Great Attractor because the arms of the Milky Way block our view of it. With today’s tools it is very difficult, nearly impossible in fact, to “see through” the interference of our own galaxy. Astrophysicists and Astronomers must look at large data sets to gain information about the Great Attractor and use maps, like the one above, to calculate what its mass should be. In many ways the Great Attractor is anomalous and Astrophysicists do not have a full explanation of it yet. Most think that it will be better understood once we can better understand what “dark matter” actually is and how it operates. The Great Attractor has even hinted at a nonuniform/asymmetric expansion of the universe.
It seems that the more that we learn about the universe, the more we realize we don’t know. There are so many mysteries that science has yet to solve, and I can’t wait to see what is learned in our lifetimes. We are very fortunate to live in an age where we are beginning to understand these mysteries. Thanks for the excellent ask, stay curious, and DFTBA!
"somewhere something incredible is waiting to be known" ~ Carl Sagan