Abell 2744, Pandora's Galaxy Cluster, Composite
Abell 2744, nicknamed Pandora's Cluster, is a giant galaxy cluster resulting from the simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years. The galaxies in the cluster make up less than five percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays. Dark matter makes up around 75 percent of the cluster's mass. The core region shows a bullet-shaped structure in the X-ray emitting hot gas and a separation between the hot gas and the dark matter. This separation occurs because electric forces between colliding particles in the clouds of hot gas create a friction that slows them down, while dark matter is unaffected by such forces. In the Northwest (NW) region, a much larger separation is seen between the hot gas and the dark matter. Surprisingly, the hot gas leads the dark clump (mostly dark matter) by about 500,000 light years. This unusual configuration may require a slingshot scenario, as suggested previously by scientists, to fling the hot gas ahead of the dark matter during an earlier interaction. In the North (N) and the West (W) two additional examples of hot gas separated from dark matter may be visible. The latter appears to exhibit the largest separation seen to date between hot gas and dark matter. Galaxy clusters are the largest gravitationally bound objects in the Universe and have become powerful tools in cosmology studies. Further studies of Abell 2744 may provide a deeper understanding of the way that these important objects grow and provide new insight into the properties of dark matter. Release date June 22, 2011.
Size: 3600px × 3600px
Photo credit: © Photo Researchers / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 2011, 21st, 2744, abell, astronomical, astronomy, body, celestial, century, cluster, composite, cosmography, cosmological, cosmology, cosmos, deep, evolution, galaxy, heavenly, image, labelled, object, pandora, science, sky, space, universe
