COPENHAGEN, Denmark, March 2 (UPI) -- A1689-zD1, a small, faint galaxy spotted in the midst of a galaxy cluster known as Abell 1689, offers astronomers the chance to peer back in cosmic time.
The galaxy is so far away that its light -- captured through the lenses of ALMA and the Very Large Telescope -- is ancient, rendering the galaxy as it was just 700 million years after the big bang. What's surprised scientists is not the galaxy's age or size, however, but its contents. The galaxy is surprisingly dusty.
Most scientific models suggest the universe, in the aftermath of the big bang, consisted of only hydrogen and helium gas -- no dust. But A1689-zD1 features lots of dust, a lot more than current theories can explain.
"Although the exact origin of galactic dust remains obscure, our findings indicate that its production occurs very rapidly," explained Darach Watson, "within only 500 million years of the beginning of star formation in the Universe -- a very short cosmological time frame, given that most stars live for billions of years."
Watson, lead researcher, is an astronomer at the University of Copenhagen and the Niels Bohr Institute.
The ratio of cosmic dust-to-gas in A1689-zD1 is what astronomers expect to find among the confines of much older galaxies. The revelation suggests early galaxies may have evolved much more quickly than previously theorized and that this particular galaxy began star formation not long after the birth of the universe.
"This amazingly dusty galaxy seems to have been in a rush to make its first generations of stars. In the future, ALMA will be able to help us to find more galaxies like this, and learn just what makes them so keen to grow up," said study co-author Kirsten Knudsen, an astronomer at Sweden's Chalmers University of Technology.
In addition to finding an excess of cosmic dust, data collected also showed the galaxy to be emitting radiation in the far infrared, meaning it had already done most of its star producing by just 700 million years after the big bang.
The new study was published Monday in the journal Nature.