The Hubble Space Telescope searches for massive galactic clusters to learn more about gravitational lensing, the distortion and magnification of light from background, more distant bodies caused by a cluster’s enormous gravity.
Globular clusters are favorite targets for amateur astronomers, offering tightly-packed swarms of stars visible in even modest telescope. But the Hubble Space Telescope’s view of M14 offers a truly jaw-dropping spectacle.
Some tightly-packed globular clusters show signs of unseen black holes affecting the movements of their stars. Astronomers are using the Hubble Space Telescope to look for evidence of such hidden monsters.
Galaxy clusters serve as gravitational zoom lenses for the Hubble Space Telescope, magnifying the light from more remote background galaxies to shed light on the nature of such lenses and the distribution of dark matter.