Astronomers have uncovered a tiny galaxy that is providing a glimpse into the past. Known as the Peekaboo Galaxy, it was only recently discovered due to its location behind a bright foreground star. The galaxy, which is only 1,200 light-years across, is the closest example yet of galaxy formation processes that commonly took place shortly after the Big Bang, 13.8 billion years ago.
The Peekaboo Galaxy is an “extremely metal-poor” (XMP) galaxy, meaning it is made up of mostly primordial hydrogen and helium, with very little heavier elements. These types of galaxies were common in the early universe, but finding one so close to Earth is rare. The Peekaboo Galaxy is located 20 million light-years away, making it at least half the distance of previously known young XMP galaxies.
The discovery was a combined effort of telescopes on the ground and in space, including confirmation by NASA’s Hubble Space Telescope. The telescope was able to resolve about 60 stars in the galaxy, all of which appear to be a few billion years old or younger. This indicates that the Peekaboo Galaxy is one of the youngest and least chemically-enriched galaxies ever detected in the local universe, which is unusual given the 13 billion years of cosmic history in the local universe.
The research team plans to use the Hubble Space Telescope and the James Webb Space Telescope to learn more about the Peekaboo Galaxy’s stellar populations and chemical makeup. The discovery of this tiny galaxy provides a unique opportunity for scientists to study galaxy formation processes in detail, giving them a window into the past.