Dark Matter

It's invisible and hard to find, but it makes up 80% of our universe.  Dark matter cannot be seen by light, as other matter.  Scientists are making headway in mapping dark matter by analyzing the chaotic galaxies.

Dark matter was first identified in the 1930's by  Fritz Zwicky, when he observed the movements of the galaxies were not matching up with the amount of mass that could be seen.  In 2006 the 'Bullet cluster' was observed by astronomers.  The 'Bullet cluster' was made up of 2 clusters of galaxies that were colliding with each other.  The clusters appeared to have a region around each of them, and when measured using gravitational lensing, this region was found to have a large amount of mass.  Using what is known as this weak gravitational lensing, the identification and measurement of dark matter because possible. (Francis, 2014)

The next step that astronomers took was in finding a way to map all of the locations of dark matter.  Princeton University astronomers Neta Bahcall and Andrea Kulier used the weak lensing process to took a weak lensing census of 132,473 galaxy groups and clusters, all within a well-defined patch of the sky but at a range of distances from the Milky Way. (Francis, 2014)

Cited Works: Francis, M. (2014, July 27). Dark matter makes up 80% of the Universe—but where is it all? Retrieved September 20, 2015.