The Milky Way Interacted with Another Galaxy to Trigger our Solar System’s Formation

While it’s well-known among the scientists that our Solar System was formed due to fundamental forces such as gravity, it looks like we still have a lot to learn about our ‘cosmic backyard’. There could be many other factors that contributed than anybody ever expected. The good news is that astronomers never stop searching for answers.

The Milky Way interacting with a smaller galaxy called Sagittarius long ago triggered the formation of the Solar System, and therefore the event had a crucial contribution to our existence as living and conscious beings.

Some scientists suspected Sagittarius’ role

Astronomers knew that the Sagittarius galaxy has contributed to establishing the trajectory for some of the stars from the Milky Way. But a new study based on data gathered by galaxy mapping Gaia spacecraft owned by the ESA (European Space Agency), reveals that Sagittarius had a much more significant role when it got closer to the Milky Way. The scientists studied the luminosities, distances, and colors of stars from a sphere of about 6,500 light-years around the Sun. They further compared the data with existing stellar evolution models.

Tomás Ruiz-Lara is the lead author of the new study, and also astrophysicist of the Instituto de Astrofísica de Canarias in Tenerife. He explained the new conclusions:

It is known from existing models that Sagittarius fell into the Milky Way three times – first about five or six billion years ago, then about two billion years ago, and finally one billion years ago.

When we looked into the Gaia data about the Milky Way, we found three periods of increased star formation that peaked 5.7 billion years ago, 1.9 billion years ago and 1 billion years ago, corresponding with the time when Sagittarius is believed to have passed through the disk of the Milky Way.

The new study was published in the journal Nature Astronomy.

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Cristian Antonescu

About the Author: Cristian Antonescu

With a strong passion for astronomy since he was little and hundreds of articles written about this field, Cristian is a reliable writer who keeps the website up-to-date with news about the wonders of the Universe.

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