This Hubble image shows the massive galaxy cluster Abell 1689 and the phenomenon of gravitational lensing with unprecedented clarity. The cluster acts like a cosmic lens, magnifying the light from objects lying behind it and making it possible for astronomers to explore incredibly distant regions of space.
Abell 1689 has been found to also host a huge population of globular clusters. While our galaxy, the Milky Way, is home to around 150 of these old clumps of stars, astronomers estimate that this galaxy cluster could possibly contain a mind-boggling 160,000 globulars overall.
In addition to the glowing golden elliptical galaxies, bright stars, and distant, ethereal spiral galaxies, the picture shows a number of blue streaks, circling and arcing around the fuzzy galaxies in the center of the image (click on the image to embiggen it). Those streaks are the signs of gravitational lensing. Abell 1689 is so massive that it actually bends and warps the space around it, affecting how light from objects behind the cluster travels through space. The streaks are distorted forms of galaxies that lie beyond the cluster. While the galaxy cluster is just over 2 billion light-years away, the lensed galaxies are over 13 billion light-years distant and are among the oldest objects we can see in visible light.
Image Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)