Seven previously unseen galaxies have been spotted by NASA's legendary Hubble telescope, giving scientists a farther look back into the universe than ever before.

Astronomers think that our universe began 13.7 billion years ago with the Big Bang. Researchers say the galaxies in this picture were formed more than 13 billion years ago, when the universe was less than 4 percent of its present age.

One of the galaxies may even be the oldest ever observed, taking shape just 380 million years after the birth of our universe. That's about 100 million years older than the galaxy NASA's space telescopes spotted in November, which at the time, was thought to be the most distant galaxy ever seen.

A look at the earliest galaxies shows that the number of galaxies increased the older the universe got. At the beginning of the universe, galaxies were small and formed slowly. They didn't just spring into exi stance all at once.

"Our data confirm re-ionization was a gradual process, occurring over several hundred million years, with galaxies slowly building up their stars and chemical elements," Brant Robertson of the University of Arizona in Tucson said in a statement. "There wasn't a single dramatic moment when galaxies formed. It was a gradual process."

Check out a picture of our universe as an infant below. The colored squares and diamonds correspond to a galaxy's redshift. A more distant galaxy has a higher redshift. The oldest galaxy observed has a corresponding redshift of 11.9, for example.

This new image of the Hubble Ultra Deep Field (HUDF) 2012 campaign reveals a previously unseen population of seven faraway galaxies, which are observed as they appeared in a period 350 million to 600 million years after the big bang.