NASA scientists who were examining the galaxy cluster Abell 2744, nicknamed Pandora’s Cluster have managed to use telescopes to piece together the galaxy’s violent past. Scientists used the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope, the Japanese Subaru telescope, and NASA’s Chandra X-ray Observatory to collect their findings, calling the area a place of a violent and complex history.
According to NASA scientists the area is a giant galaxy cluster of at least four separate smaller galaxy clusters that collided in an epic crash more than 350 million years ago.
According to findings published on the official NASA Website:
The galaxies in the cluster make up less than 5 percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays (colored red in this image). The distribution of invisible dark matter (making up around 75 percent of the cluster’s mass) is colored here in blue.
Dark matter does not emit, absorb, or reflect light, but it makes itself apparent through its gravitational attraction. To pinpoint the location of this elusive substance the team exploited a phenomenon known as gravitational lensing. This is the bending of light rays from distant galaxies as they pass through the gravitational field created by the cluster. The result is a series of telltale distortions in the images of galaxies in the background of the Hubble and VLT observations. By carefully analyzing the way that these images are distorted, it is possible to accurately map where the dark matter lies.
If the original findings are correct it could mean that during the collision some hot gas was separated from dark matter and now lie apart from one another and from visible galaxies.
Look towards the middle of the cluster for the “bullet” to see where the gas of one cluster has collided with the gas of another cluster to create a shock wave while the dark matter passed through the collision without harm.
In another part of the cluster, galaxies and dark matter can be found, but no hot gas. The gas may have been stripped away during the collision, leaving behind no more than a faint trail.