First stars started to shine 100m years later than previously thought

A new study has recently revealed that first stars started to shine 100 million years later than previously thought, as they started to shine around 550 million years after the Big Bang.

New maps from ESA's Planck satellite uncover the "polarized" light from the early universe across the entire sky, revealing that the first stars are actually younger than previously thought.

They also include information about our own Milky Way, showing that the contribution from dust in our galaxy is much more widespread than previously thought and revealing complex structures in the galactic magnetic field.

Researchers at the Max Planck Institute for Astrophysics developed important software components for Planck and take part in the scientific interpretation of the mission data; in particular, they contributed to the analysis of the signals from galaxy clusters, from gravitational lensing of the CMB, from galactic dust and magnetic fields, as well as from primordial magnetic fields.

The big bang 13.8 billion years ago was when matter, space and even time exploded into existence. Previously scientists had thought that the first stars began to shine 440 million years after the big bang. The new results, still to be confirmed by further measurements, suggested that they are 100 million years younger.

However, as the CMB light travelled through space and time it was also influenced by the first stars-and the polarization data now indicates that these started to shine about 550 million years after the Big Bang, ending the "Dark Ages."

This was more than 100 million years later than previously thought but actually helps to resolve a problem: Previous studies of the CMB polarization seemed to point towards an earlier dawn of the first stars, while very deep images of the sky indicated that the earliest known galaxies in the universe (forming perhaps 300-400 million years after the Big Bang) would not have been powerful enough to succeed at ending the Dark Ages within 450 million years.

The new evidence from Planck significantly reduces the problem, indicating that the earliest stars and galaxies alone might have been enough.

The study is published in the journal Astronomy and Astrophysics.