The latest pictures, captured by new cameras installed on the orbiting telescope, show clumps of stars whose light has taken more than 12 billion years to reach Earth - meaning that they began to burn not long after the Big Bang about 15 billion years ago.
"This is just our first tentative glimpse into the very remote universe," said Alan Dressler, an astronomer at the Carnegie Observatories in Pasadena, California. "What we see here may be the first stages of galaxy formation. But these objects are so faint that their true nature can only be explored with the advanced telescopes of the future."
Cosmologists are confident that the Big Bang created all the matter and energy in the universe, but astronomers are now keen to push back the limits of vision to see when the first stars formed from the primeval mix and began to burn, giving off light.
"[Hubble] has parted the dark curtain that previously blocked out view of very distant objects and revealed a whole new cast of characters," said Rodger Thompson of the University of Arizona, Tucson. "We now have to study them to find out what and where they are. We are still finding new frontiers."
Knowing how the first stars and galaxies began to shine will provide clues about the exact age and composition of the early universe, as well as indicating how our own Sun - made, like the Earth, from the remnants of stars which exploded billions of years ago - would have formed.