Galaxy Cluster Abell 520's mass (HST WFPC2) This image shows the
location of most of the mass in merging galaxy cluster Abell
520's core, which is dominated by dark matter. Dark matter is an
invisible substance that makes up most of the Universe's mass.
The dark-matter map was derived from Hubble Wide Field Planetary
Camera 2 observations, by detecting how light from distant
objects is distorted by the cluster galaxies, an effect called
gravitational lensing. Abell 520 resides 2.4 billion light-years
away. About the Image About the Object |Type:||• Early Universe
: Galaxy : Grouping : Cluster| • Early Universe : Cosmology :
Phenomenon : Dark Matter • Cosmology Images/Videos |Distance:||2
billion light years|