Gaia Satellite Finds Evidence Of A Massive Collision Between Milky Way And A Dwarf Galaxy

Posted: Jul 4 2018, 4:15pm CDT | by , Updated: Jul 4 2018, 11:38pm CDT, in Latest Science News


This story may contain affiliate links.

Gaia Satellite Finds Evidence of a Massive Collision Between Milky Way and a Dwarf Galaxy
An impression of the encounter between the Milky Way galaxy and the smaller Sausage galaxy about 8 billion to 10 billion years ago. Credit: V. Belokurov (Cambridge, UK)

New study says that around 10 billion years ago small "Sausage" galaxy crashed into the Milky Way and created its inner bulge and outer halo

Astronomers have found evidence of a massive cosmic collision that reshaped the structure of our galaxy Milky Way. Based on observations from Gaia satellite, researchers conclude that around 8 billion to 10 billion years ago, an unknown dwarf galaxy crashed into Milky Way and triggered dramatic consequences. Because of the collision, the dwarf galaxy disintegrated in the space, and its stars were thrown into different orbits. The broken pieces of galaxy dubbed the “Sausage” are still around us even today.

“The collision ripped the dwarf to shreds, leaving its stars moving in very radial orbits" that are long and narrow like needles,” said Vasily Belokurov of the University of Cambridge. The stars' paths take them "very close to the center of our galaxy. This is a telltale sign that the dwarf galaxy came in on an eccentric orbit and its fate was sealed."

The observations were made possible by European Space Agency’s Gaia satellite. Gaia has been measuring the positions and distances of the stars in our galaxy with unprecedented accuracy and helping astronomers understand the origin and evolution of Milky Way. By mapping journeys of stars, as they travel through the Milky Way, researchers provide clues on that head-on cosmic collision, which they believe was the was a defining event in the early history of the Milky Way.

“We plotted the velocities of the stars, and the sausage shape just jumped out at us. As the smaller galaxy broke up, its stars were thrown onto very radial orbits. These Sausage stars are what's left of the last major merger of the Milky Way.” Wyn Evans of the University of Cambridge explained.

Galaxies are held together by mutual gravity, and their interaction is relatively frequent, especially between giant ones and their dwarf satellites. Sometimes galaxies drift too close to one another that they collide and begin to merge. In such cases, more massive galaxies remain mostly intact and retain their shape, while the smaller galaxy fell to pieces and become part of the larger galaxy.

Several dwarf galaxies such as the Sagittarius Dwarf Galaxy are currently colliding with the Milky Way. Scientists predict that Andromeda, the closest and a major spiral galaxy to our galaxy, is also on a collision course with Milky Way. The Sausage galaxy was another massive galaxy that had a total mass more than 10 billion times the mass of our sun and its debris was scattered all around the inner parts of the Milky Way, creating the bulge at the galaxy's center and the surrounding stellar halo.

Sergey Koposov of Carnegie Mellon University, who has studied the kinematics of the Sausage stars and globular clusters in detail, says. "While there have been many dwarf satellites falling onto the Milky Way over its life, this was the largest of them.

This story may contain affiliate links.


Find rare products online! Get the free Tracker App now.

Download the free Tracker app now to get in-stock alerts on Pomsies, Oculus Go, SNES Classic and more.

Latest News


The Author

<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.




comments powered by Disqus