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| Credit - Google || Image Taken from Flickr.com |
An international team of astronomers has discovered the most distant galaxy yet—and it’s truly ancient. Located 12.9 billion light-years away, it has been around nearly since the beginning of time itself, meaning that we’re seeing it as it appeared within a few hundred million years of the Big Bang itself (the present age of the universe is 13.8 billion years). The galaxy, named GN-z11, existed just 400 million years after the Big Bang and contains some 300 billion stars—10 times more than our Milky Way galaxy does today.
The discovery
In a major step toward understanding how galaxies form and evolve, astronomers have discovered by far the most distant galaxy ever seen. Named GN-z11, it appears to have been lit up only 400 million years after the Big Bang, making it possible for astronomers to observe fundamental changes occurring during that epoch. The light that now reaches us from GN-z11 has traveled for 13.4 billion years across space and time, starting out as visible light before being shifted into infrared wavelengths due to its great distance from Earth.
A history of galaxies
Galaxies are some of most important objects in Astrophysics. They have a tendency to form at a rate proportional to their distance from each other (Hubble’s Law). The more distant ones are generally smaller in size, and include a high ratio of gas to stars. This is consistent with what we know about star formation - young and old stars tend to form in clusters with hot-gas clouds, while middle-aged stars like our sun tend to be found alone or in pairs. Over time, though, galaxies will merge together as they fall into massive clusters like our local cluster of galaxies, called Virgo.
The researchers
Ryan Foley, a University of California at Santa Cruz astronomy graduate student; Richard Ellis, an astronomer at UCO/Lick Observatory in California; and Adam Leroy of Ohio State University. The research will be published in an upcoming issue of Astrophysical Journal Letters.
Galactic evolution
Scientists discovered one of the most distant galaxies ever found. The galaxy, named EGS-zs8-1, is 13.2 billion light years away from Earth and measures only 200,000 light years across — nearly 2 million times smaller than our own Milky Way galaxy. This discovery pushes back evidence for when galaxies started to form by almost 700 million years.
The Milky Way and our place in the universe
The Milky Way is our galaxy. It’s so big that we can only see about half of it at any one time—the rest is on the other side of our galaxy, where we can’t see from Earth because of thick dust clouds. It consists of a disk-shaped collection of stars, gas and dust and it’s about 100,000 light years across. Our solar system lies in one of its spiral arms.
Galaxies die, but stars live on forever
Astronomers using NASA’s Hubble Space Telescope have discovered that a certain class of gigantic, star-forming galaxies were more numerous in the past than they are today. Galaxies grow through collisions and mergers with other galaxies. This is a slow process that occurs over billions of years and results in large elliptical galaxies with aging stars. The farthest and youngest galaxy found by Hubble, seen as it appeared 13 billion years ago, already has settled into an evolved form.
What was their galaxy like?
What we can learn from this discovery
That might be a whole other paper for another day, but here’s what we know about UDFy-38135539 so far. The galaxy is thought to have been born at around a time when cosmic structures were just beginning to form, 13.2 billion years ago. As such, it provides astronomers with an excellent opportunity to study how these structures evolved in early galaxies and if they resemble anything seen in our own Milky Way today.