The galaxy repeatedly pierced the Milky Way

The Sagittarius dwarf galaxy, about 26,000 light-years from the Milky Way galaxy, could be a boost to the Sun's formation.

Researcher Tomás Ruiz-Lara at the Canary Islands Astrophysical Institute, Spain, and his colleagues analyzed data from the Gaia space telescope to measure the age of stars within 6,500 light years around the system. The Sun, New Scientist reported on 25/5.

Sagittarius' path through the galaxy disk of the Milky Way. (Photo: New Scientist).

The team of experts discovered that there were three periods of new star intensifying formation, occurring about 5.7 billion years, 1.9 billion years and 1 billion years ago. They also found signs that a new star explosion began 70 million years ago and seems to continue today. The bursts coincided with the moment when the Sagittarius dwarf galaxy pierced the Milky Way.  

Sagittarius orbits the Milky Way and is also one of the nearest galaxies. Although the size is less than 1/10 of the Milky Way, Sagittarius still seems to have a great influence on the formation of stars here. Even the solar system is likely formed after the collision of 5.7 billion years ago.

"The Milky Way is in a state of equilibrium, still. The passage of Sagittarius is like throwing a stone into a lake," Ruiz-Lara said. It causes ripples in the Milky Way's dust cloud, making some areas denser and starting to form new stars more efficiently.

"Perhaps without Sagittarius, the solar system would not exist , " Ruiz-Lara said. He said the time when the Solar System formed coincided with the first Sagittarius crashed into the Milky Way, but could not confirm with certainty that the collision was the cause.

The number of such collisions is likely to occur more and more frequently as the orbit of Sagittarius around the Milky Way is shrinking. "Sagittarius is getting closer and closer, eventually merging with the Milky Way," Ruiz-Lara said.