NASA’s Hubble Space Telescope is excellent in observing multitudes of galaxies tossed across time and space. A remarkable example is Abell 370, a galaxy cluster, which comprises of several hundred assorted galaxies bound together by the collective pull of gravity.
The huge cluster, located 4 billion light-years away, was photographed in a blend of visible and near-infrared light. The largest and brightest galaxies in the cluster are the immense, yellow-white, elliptical galaxies each comprising of several hundreds of billions of stars. The spiral galaxies are bluish and have younger populations of stars.
Intertwined among the galaxies are strange-looking blue light arcs. These actually are distorted images of distant galaxies beyond the cluster. These remote galaxies are very vague for Hubble to see directly. However, the cluster functions as a massive lens in space which stretches and magnifies images of the galaxies behind like a funhouse mirror.
The huge gravitational field of the forefront cluster results in this phenomenon. The mutual gravity of the stars and other matter caught inside the cluster twists space and disturbs light passing toward earth through the cluster. This lensing-effect causes multiple images of almost a hundred remote galaxies.