Like a cosmic wayback machine, NASA’s Spitzer Space Telescope looks back in time at various galactic clusters.

These snapshots represent clusters of galaxies at different stages of the universe’s history, ranging from 8.15 billion years ago (a cluster about 8.15 billion light-years away) to 9.09 billion years ago (or 9.09 billion light-years away). Scientists believe the universe is about 13.7 billion years old.

Hundreds of galaxies, and possibly trillions of stars, make up the typical galactic cluster. Spitzer turned its infrared lens on four such clusters at different wavelengths, generating the red points that indicate cluster galaxies. The large green blots are stars in our own Milky Way galaxy that happen to be in the in line of sight of Spitzer’s view, while the blue points are faint galaxies at varying distances between the Milky Way and Spitzer’s observations. Both the green and blue wavelength observations were made by ground-based telescopes observing in the visible range of the light spectrum.

At nearly 9.1 billion light-years from Earth, the galaxy cluster in the lower right frame is the most distant ever recorded, Spitzer researchers said.

-- SPACE.com Staff

Credit: NASA/JPL-Caltech/UCDavis/Lawrence Livermore National Laboratory.