Farthest Galaxy in the Universe Spotted, Existing Just After the Big Bang

First Posted: Sep 04, 2015 04:15 PM EDT

Scientists may have spotted a galaxy that formed just after the universe did. They've peered back in time to just after the Big Bang to see a galaxy that's more than 13.2 billion years old.

The galaxy, in this case, is called EGS8p7. It was identified earlier this year as a candidate for further investigation based on data gathered from NASA's Hubble Space Telescope and the Spitzer Space Telescope.

The researchers actually determined the redshift of the galaxy. Redshift results from the Doppler effect, the same phenomenon that causes the siren on a fire truck to drop in pitch as the truck passes. With objects in the galaxy, it is light that is being "stretched" rather than sound.

It's actually difficult to determine the redshift for galaxies immediately after the Big Bang. At the time, photons were scattered by free electrons, which meant that the early universe could not transmit light. About 380,000 years after the Big Bang, though, the universe had cooled enough for free electrons and protons to combine into neutral hydrogen atoms that filled the universe, allowing light to travel. When the universe was just a half-billion to a billion years old, the first galaxies turned on and reionized the neutral gas.

Before reionization, though, clouds of neutral hydrogen atoms would have absorbed certain radiation emitted by young, newly forming galaxies, including the so-called Lyman-alpha line, which is the spectral signature of hot hydrogen gas that has been heated by ultraviolet emission from new stars, and a commonly used indicator of star formation.

"The surprising aspect about the present discovery is that we have detected this Lyman-alpha line in an apparently faint galaxy at a redshift of 8.68, corresponding to a time when the universe should be full of absorbing hydrogen clouds," said Richard Ellis, one of the researchers, in a news release.

The findings reveal that the galaxy is the farthest ever discovered, which means that it could tell scientists a bit more about the early universe.

The findings are published in The Astrophysical Journal.

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TagsBig Bang, Galaxy, Universe, space, Hubble Telescope, Hubble Space Telescope, Spitzer Space Telescope