Hubble eXtreme Deep Field, Credit: NASA, ESA, Hubble
The Hubble eXtreme Deep Field (XDF) covers a tiny patch of sky not much bigger than the largest crater on the moon. Hubble spent almost 23 days imaging this tiny patch of sky to give us this incredible image. 5,300 galaxies are visible in this image! The universe is 13.7 billion years old, and the youngest galaxy in this image is only 450 million years after the big bang.