London, March 3: Debunking earlier theories that earliest galaxies had no dust but gas, an international team of astronomers has discovered a dust-filled galaxy from the very early universe.
The discovery shows that galaxies were very quickly enriched with dust particles containing elements such as carbon and oxygen which could form planets.
"It is the first time dust has been discovered in one of the most distant galaxies ever observed - only 700 million years after the Big Bang. It is a galaxy of modest size and yet it is already full of dust," said Darach Watson, astrophysicist from the Niels Bohr Institute at University of Copenhagen, Denmark.
"This is very surprising and it tells us that ordinary galaxies were enriched with heavier elements far faster than expected," Watson added.
Young stars in early galaxies emitted hot ultraviolet light.
The hot ultraviolet radiation heats the surrounding ice-cold dust, which then emits light in the far-infrared.
"It is this far-infrared light, which tells us that there is dust in the galaxy. It is very surprising and it is the first time that dust has been found in such an early galaxy," the authors said.
The process of star formation must have started very early in the history of the universe and be associated with the formation of dust.
"The detection of large amounts of solid material shows that the galaxy was enriched very early with solids which are a prerequisite for the formation of complex molecules and planets," Watson said.
The researchers hope that future observations of a large number of distant galaxies could help unravel how frequently such evolved galaxies occur in this very early epoch of the history of the universe.
Dust plays an extremely important role in the universe - both in the formation of planets and new stars.
The results were published in the scientific journal Nature.