The first stars were formed much later than had been previously thought in the boffinry community, according to new maps of the universe's "ancient light" from the European Space Agency's Planck satellite.

Astrophysicists have now calculated that the universe is roughly 13.8 billion years old, based on the light emitted by distant stars, galaxies and the matter spread between them.

A major source of information has been the Cosmic Microwave Background (CMB), the fossil light resulting from a time when the Universe was hot and dense, only 380 000 years after the Big Bang.

That light covers the whole sky at microwave wavelengths due to the expansion of the universe.

Between 2009 and 2013, Planck surveyed the sky to study this ancient light in unprecedented detail, the ESA said.

Marco Bersanelli of the Università degli Studi di Milano said:

"Planck’s observations of the CMB polarisation now tell us that these ‘Dark Ages’ ended some 550 million years after the Big Bang – more than 100 million years later than previously thought.

“While these 100 million years may seem negligible compared to the Universe’s age of almost 14 billion years, they make a significant difference when it comes to the formation of the first stars.”

Tiny differences in the background’s temperature trace regions of slightly different density in the early cosmos, representing the seeds of all future structure, the stars and galaxies of today, it said.

Jan Tauber, ESA’s Planck project scientist, said the CMB carries additional clues about our cosmic history that are encoded in its "polarisation".

He added: “These are only a few highlights from the scrutiny of Planck's observations of the CMB polarisation, which is revealing the sky and the Universe in a brand new way,” says Jan Tauber.

“This is an incredibly rich data set and the harvest of discoveries has just begun.”

There's more on the discoveries from the ESA here. ®