This Hubble Space Telescope image represents the largest, most comprehensive « history book » of galaxies in the universe.The image, a combination of nearly 7,500 separate Hubble exposures, represents 16 years’ worth of observations.The ambitious endeavor, called the Hubble Legacy Field, includes several Hubble deep-field surveys, including the eXtreme Deep Field (XDF), the deepest view of the universe. The wavelength range stretches from ultraviolet to near-infrared light, capturing all the features of galaxy assembly over time.The image mosaic presents a wide portrait of the distant universe and contains roughly 265,000 galaxies. They stretch back through 13.3 billion years of time to just 500 million years after the universe’s birth in the big bang. The tiny, faint, most distant galaxies in the image are similar to the seedling villages from which today’s great galaxy star-cities grew. The faintest and farthest galaxies are just one ten-billionth the brightness of what the human eye can see.The wider view contains 100 times as many galaxies as in the Hubble Ultra Deep Field, taken in 2004. The new portrait, a mosaic of multiple snapshots, covers almost the width of the full Moon. Lying in this region is the XDF, which penetrated deeper into space than this legacy field view. However, the XDF field covers less than one-tenth of the full Moon’s diameter.
Astronomers have put together the largest and most comprehensive “history book” of galaxies into one single image, using 16 years’ worth of observations from NASA’s Hubble Space Telescope.