Researchers at the University of Vienna have discovered a river of 4,000 stars flowing past Earth.

According to the findings, the stars within the stream formed around a billion years ago.

The "star stream", which was found passing incredibly close to Earth, could provide us with valuable information about how star clusters form.



According to recent findings published in Astronomy and Astrophysics, researchers at the University of Vienna have discovered a river of 4,000 stars flowing past the Earth — at an incredibly short distance of 326 lightyears.

According to the press release, the stars within the stream formed around a billion years ago and have been moving together through space.

Measuring around 1,305 lightyears long, the stream has the potential to provide the scientists with all sorts of valuable insights on how star clusters form and how they can be destroyed.

"Finding things close to home is very useful, it means they are not too faint nor too blurred for further detailed exploration, as astronomers dream," said astrophysicist João Alves of the University of Vienna.

In the Milky Way there are several stars clusters, all of varying sizes and ages. These clusters, irrespective of their age or origin, are all affected by tidal forces along their orbits in the galaxy.

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With time, the gravitational forces of the Milky Way eventually tear the clusters apart, dispersing their stars into what we call Milky Way.

Gaia's all-sky view of the Milky Way and neighbouring galaxies. ESA/Gaia/DPAC

"Most star clusters in the Galactic disk disperse rapidly after their birth as they do not contain enough stars to create a deep gravitational potential well, or in other words, they do not have enough glue to keep them together. There are, however, a few clusters with sufficient stellar mass to remain bound for several hundred million years," said Stefan Meingast, lead author of the study.

Essentially, a lot of mass is needed to hold the stars together.

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"Identifying nearby disk streams is like looking for the proverbial needle in a haystack. Astronomers have been looking at, and through, this new stream for a long time, as it covers most of the night sky, but only now realize it is there, and it is huge, and shockingly close to the Sun," said João Alves, the second author of the paper.

The Gaia mission keeps on giving

Launched by the European Space Agency in 2013, the main purpose of the space observatory the scientists used to discover the stream — Gaia — is to form a three-dimensional map of our galaxy and the Milky Way.

The Milky Way from Earth. Anton Jankovoy/Shutterstock

Without Gaia, the researchers wouldn't have been able to ascertain the exact position of the stars and their speed nor, in turn, to properly identify the stellar stream.

Though they were only able to clearly make out 200 stars, the way the stars were interacting and shifting together meant the scientists were able to confirm the stream contained at least 4,000 other stars.

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The researchers are now hoping to put these findings to use and to use them to help work out how galaxies are formed, as well as how gravitational forces work.