Astronomers have observed the most distant galaxy yet by detecting photons emitted from its clouds of hydrogen when the 13.8-billion-year-old Universe was less than 600 million years old.

Such photons rarely make it to telescopes on Earth, but Adi Zitrin at the California Institute of Technology in Pasadena and his colleagues were able to detect them using a telescope at the W. M. Keck Observatory in Mauna Kea, Hawaii. They found that the wavelength of arriving photons had been stretched en route, indicating that the galaxy, named EGSY8p7, is more than 13.2 billion light years (4 billion parsecs) away.

Seeing hydrogen emission from such a distant galaxy may challenge current understanding of the evolution of the Universe, the authors say.

Astrophys. J. Lett. 810, L12 (2015)