Galactic births came early

NASA, ESA, J. Richard (CRAL) and J.-P. Kneib (LAM). Acknowledgement: Marc Postman (STScI)

The giant cluster of elliptical galaxies in the centre of this image, called Abell 383, was used as a gravitational lens to study a galaxy that formed less than a billion years after the big bang. The galaxy's stars formed when the universe was just 200 million years old. The finding has implications for our understanding of how and when the first galaxies formed, and how the diffuse fog of neutral hydrogen that filled the early Universe was cleared.

A distant galaxy with stars that began forming just 200 million years after the big bang has been discovered. The finding addresses questions about when the first galaxies arose and how early the universe evolved, scientists report.

The galaxy was spotted with the Hubble Space Telescope. It is visible through a cluster of galaxies called Abell 383, whose powerful gravity bends the rays of light like a magnifying glass. The so-called gravitational lens amplifies light from the distant galaxy, making it appear 11 times brighter and allowing detailed observations.

Infrared data from Hubble and NASA's Spitzer Space Telescope show the galaxy's stars formed when the universe was 200 million years old. Observations with the W.M. Keck Observatory on Muna Kea in Hawaii revealed the observed light from the galaxy dates to when the universe was 950 million years old. The universe formed about 13.7 billion years ago.

"This challenges theories of how soon galaxies formed in the first years of the universe," Johan Richard of the Centre de Recherche Astronomique de Lyon, Universita Lyon 1 in France, said in an image advisory. "It could even help solve the mystery of how the hydrogen fog that filled the early universe was cleared."

At some point in our universe’s early history, it transitioned from the so-called dark ages to a period of light, as the first stars and galaxies began to ignite. This starlight ionized neutral hydrogen atoms floating around in space, giving them a charge, NASA explained. Ultraviolet light could then travel unimpeded through what had been an obscuring fog.

The discovery of a galaxy possessing stars that formed only 200 million years after the big bang helps astronomers probe this cosmic reionization epoch. When this galaxy was developing, its hot, young stars would have ionized vast amounts of the neutral hydrogen gas in intergalactic space.

A population of similar galaxies probably also contributed to this reionization, but they are too faint to see without the magnifying effects of gravitational lensing. NASA's James Webb Telescope, scheduled to launch later this decade, will be able to see these faint galaxies without magnification.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).