Hubble and Chandra composite of the galaxy cluster MACS J0025.4-1222
Date: 27 August 2008
Satellite: Hubble Space Telescope
Depicts: MACS J0025.4-1222
Copyright: NASA, ESA, CXC, M. Bradac (University of California, Santa Barbara, USA), and S. Allen (Stanford University, USA)
This astounding view of galaxy cluster MACS J0025.4-1222 demonstrates how ordinary matter and mysterious dark matter interact. The blue cloud-shaped parts flanking the centre show the position of dark matter, mapped by the Advanced Camera for Surveys (ACS) onboard the NASA/ESA Hubble Space Telescope. The pink middle indicates ordinary matter, charted by NASA's Chandra X-Ray Observatory.
The position of the two matter types shown in the image are explained by MACS J0025.4-1222's origin. It was formed when a pair of large galaxy clusters collided. Ordinary matter in the form of hot gas slowed down and pooled at the centre but ghostly dark matter passed straight through.
Hubble used a technique known as gravitational lensing to obtain its data. The light observed was bent by the gravitationally massive galaxy cluster, resulting in an incredibly detailed image. This technique was originally predicted by Einstein.
MACS J0025.4-1222 is located in the constellation Cetus, the Whale.
