A team of scientists announced Wednesday that NASA’s Hubble Space Telescope has produced a comprehensive snapshot of the “cosmic dawn” of the universe, capturing a set of seven primitive galaxies that formed several hundred million years after the big bang.

“The situation is similar to having the first ultrasound of an infant,” said Avi Loeb, chairman of the astronomy department at Harvard University who praised the new data, saying it heralds the beginning of a transformation for a field that has thus far been largely theoretical. “These early galaxies represent the building blocks of the present-day galaxies that we have.”