By collecting faint light over many hours of observation, it revealed thousands of galaxies, both nearby and very distant, making it the deepest image of the universe ever taken at that time. The full-color XDF image (which you can download here) reaches much fainter galaxies and includes very deep exposures in red light from Hubble's infrared camera, enabling new studies of the earliest galaxies in the universe. The XDF contains about 5,500 galaxies even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness of what the human eye can see.
Astronomers continue studying this area of sky with Hubble. Extensive ongoing observing programs, led by Harry Teplitz and Richard Ellis at the California Institute of Technology, will allow astronomers to study the deep-field galaxies with Hubble to even greater depths in ultraviolet and infrared light prior to the launch of JWST. These new results will provide even more extraordinary views of this region of the sky and will be shared with the public.