Astronomers at Durham University have found evidence that some of the earliest galaxies to form after the Big Bang are orbiting our own Milky Way.
The team from the Institute for Computational Cosmology, working with the Harvard-Smithsonian Center for Astrophysics described the research as "hugely exciting" and the "astronomical equivalent to finding the remains of the first humans that inhabited the Earth".
Two clusters of galaxies were identified, both thought to more than 13 billion years old and including Segue-1, Bootes I, Tucana II and Ursa Major I.
Professor Carlos Frenk, Director of Durham University's Institute for Computational Cosmology, said: "Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.
"Our finding supports the current model for the evolution of our Universe, the 'Lambda-cold-dark-matter model' in which the elementary particles that make up the dark matter drive cosmic evolution."
The Lambda-cold-dark-matter model expands on the Big bang theory helps explain the expansion of the universe and formation of galaxies.
it postulates that when the Universe was about 380,000 years old, the very first atoms formed. These were hydrogen atoms, the simplest element in the periodic table.
These atoms collected into clouds and began to cool gradually and settle into the small clumps or "halos" of dark matter that emerged from the Big Bang.
This cooling phase, known as the "Cosmic dark ages", lasted about 100 million years.
More from Science & Tech
Eventually, the gas that had cooled inside the halos became unstable and began to form stars – these objects are the very first galaxies ever to have formed.
With the formation of the first galaxies, the Universe burst into light, bringing the cosmic dark ages to an end.