Astronomers Discover Oldest Galaxies In The Universe

Posted: Aug 19 2018, 11:34am CDT | by , in Latest Science News


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Astronomers Discover Oldest Galaxies in the Universe
Credit: Institute for Computational Cosmology, Durham University, UK/ Heidelberg Institute for Theoretical Studies

Some of the first galaxies could be over 13 billion years old.

Astronomers have identified some of the oldest galaxies in the universe. Surprisingly, they are located very close to our own galaxy Milky Way and some of these are more than 13 billion years old. This means that these faint satellite galaxies formed very early in the history of the universe.

"Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.” Professor Carlos Frenk from Durham University said in a statement.

For millions of years after the Big Bang, there were no stars or galaxies. When the Universe was about 380,000 years old, the very first hydrogen atoms formed. This hydrogen gas dominated the universe throughout the “Cosmic Dark Ages,” a period that lasted about 100 million years. When clouds of primordial hydrogen collapsed under their own gravity, they became stars and eventually galaxies. And the light emitted from the first galaxies brought the cosmic dark ages to an end.

The very faint population of the galaxies from the cosmic dark ages was the earliest galaxies in the universe. Their intense ultraviolet radiation destroyed the remaining hydrogen atoms and caused ionization, making it difficult for this gas to cool and form new stars. As a result, no new galaxies were able to form for the next billion years or so.

When the halos of dark matter became so massive that even ionized gas was able to cool, the process of galaxy formation resumed and led to the formation of spectacular galaxies like our own Milky Way. This second population of galaxies was slightly brighter than the first ones.

"A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar. With the increasing sensitivity of present and future galaxy censuses, a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes,” said Dr. Alis Deason, a researcher at Durham University.

"This is a wonderful example of how observations of the tiniest dwarf galaxies residing in our own Milky Way can be used to learn about the early Universe."

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<a href="/latest_stories/all/all/47" rel="author">Hira Bashir</a>
The latest discoveries in science are the passion of Hira Bashir (). With years of experience, she is able to spot the most interesting new achievements of scientists around the world and cover them in easy to understand reporting.




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