Astronomers have assembled the deepest-ever view of the universe. Called the eXtreme Deep Field, or XDF, the photo was assembled by combining 10 years of NASA Hubble Space Telescope photographs taken of a patch of sky at the centre of the original Hubble Ultra Deep Field. The new full-colour XDF image contains about 5,500 galaxies even within its small field of view. The faintest galaxies are one ten-billionth the brightness of what the human eye can see.
NASA