New data shows galaxies accompanying the Milky Way weren't always here

ESA's Gaia mission has released new data, showing galaxies thought to have been orbiting the Milky Way for eons are newcomers.

@AdamHuntTT
Published Fri, Nov 26 2021 7:05 AM CST   |   Updated Fri, Dec 17 2021 7:32 AM CST

In a newly released data dump by the European Space Agency's (ESA) Gaia mission, what we thought of as satellite galaxies to the Milky Way are not all they seem.

New data shows galaxies accompanying the Milky Way weren't always here 01 | TweakTown.com

For decades scientists have believed the dwarf galaxies surrounding the Milky Way to be satellites, galaxies orbiting our own that have been doing so for billions of years. However, new data from ESA's Gaia mission has been used to calculate the movements of these galaxies, revealing they aren't orbiting the Milky Way at all.

Researchers computed the three-dimensional velocities for forty dwarf galaxies around the Milky Way, then used them to calculate the galaxy's orbital energies and angular (rotational) momentum. They found the galaxies to be moving significantly faster than other giant stars and star clusters known to orbit the Milky Way. The research team concluded that the dwarf galaxies could not yet be orbiting the Milky Way, as it would have attenuated their orbital energies and angular momentum.

The Milky Way has consumed smaller galaxies in the past, such as the dwarf galaxies Gaia-Enceladus and Sagittarius, 8-10 billion years ago and 4-5 billion years ago, respectively. Stars from both galaxies can be seen in the data from Gaia, where stars absorbed from Sagittarius possess higher orbital energies compared to those from Gaia-Enceladus, indicating their shorter exposure to the Milky Way's influence. The even higher energies of the dwarf galaxies now being studied indicate they have been around the Milky Way for even less time than Sagittarius.

"Some of [the dwarf galaxies] will be captured by the Milky Way and will become satellites. The Milky Way is a big galaxy, so its tidal force is simply gigantic and it's very easy to destroy a dwarf galaxy after maybe one or two passages," says Francois Hammer of the Universite Paris Sciences et Lettres.

Eventually, it seems these dwarf galaxies will meet one of two fates, integrating into the Milky Way or escaping to another region of the universe and living.

"Thanks in large part to Gaia, it is now obvious that the history of the Milky Way is far more storied than astronomers had previously understood. By investigating these tantalizing clues, we hope to further tease out the fascinating chapters in our galaxy's past," says Timo Prusti, Gaia Project Scientist at the European Space Agency.

You can read more from the researcher's study here.

Buy at Amazon

Bathsheba Sculpture The Milky Way Galaxy Star Crystal

TodayYesterday7 days ago30 days ago
$91.63$89.99$89.99
* Prices last scanned on 1/21/2022 at 5:00 am CST - prices may not be accurate, click links above for the latest price. We may earn an affiliate commission.
NEWS SOURCES:phys.org,

Adam grew up watching his dad play Turok 2 and Age of Empires on a PC in his computer room, and learned a love for video games through him. Adam was always working with computers, which helped build his natural affinity for working with them, leading to him building his own at 14, after taking apart and tinkering with other old computers and tech lying around. Adam has always been very interested in STEM subjects, and is always trying to learn more about the world and the way it works.

Newsletter Subscription

Related Tags

Newsletter Subscription
Latest News
View More News
Latest Reviews
View More Reviews
Latest Articles
View More Articles