The Milky Way ate one of its neighbors 10 billion years ago | Smart News

New research suggests about 10 billion years ago that the Milky Way consumed a smaller galaxy, and the remains of this cosmic lunch are still swirling in the belly of the Milky Way.

The party was discovered when researchers examined data collected by the European Space Agency's Gaia space telescope, analyzing data on tens of thousands of stars within 33,000 light-years of our own sun, reports Lisa Grossman at ScienceNews. The data show that a group of about 30,000 of these stars do not rotate around the galactic center as they should. Instead, they seem to move in the opposite direction.

"It was the first clue," said astronomer Amina Helmi of the University of Groningen in the Netherlands. "When the stars move in the opposite direction, it already tells you that they did not form in the same place as the majority of stars in our galaxy."

Using the galactic evolutionary experience of the Apache Point Observatory in New Mexico, Amina and her colleagues followed up, examining the building blocks of the stars. The chemical composition has shown that receding stars do not contain the same heavy elements as stars like ours. Instead, they appear to be much older, forming before the cycle of birth and death of massive stars that propagate heavier elements into the universe, according to a new study published in the newspaper Nature.

The team knew that the stars had formed elsewhere, but they did not know how they ended up floating around the Milky Way. Using computer simulations, they worked in the back and determined that about 10 billion years ago, an old galaxy the size of our planet gravitates around the Milky Way. Eventually, the two collided. Our cosmic house then invaded the smallest galaxy, now called Gaia-Enceladus, absorbing about 600 million solar masses of matter.

Gaia-Enceladus is not the only galaxy swallowed up by the Milky Way, says astronomer Kathryn Johnston of Columbia University at Meghan Bartels of Space.com.

"The milky way is a cannibal. He has eaten many dwarf galaxies in the past, and we have found a major one he has eaten in the past, "she says. "It's like a police investigation – this particular one, because it's not a galaxy we can see today. It's a dead galaxy, so it makes things fun. "

Research done at the beginning of the year shows that the Milky Way is still a bit hungry. There are two small gaseous galaxies in orbit around ours, known as big and small magellanic clouds, which also gravitate around one another. Researchers have determined that the Milky Way is drinking gas from the Little Magellanic Cloud, using this material to produce new stars and planets.

And the Milky Way is not the only cannibal in the region. Our galaxy is part of a team of about 30 neighboring galaxies called The Local Group. As the largest galaxies of the crew, the Milky Way and Andromeda of similar size are the most dominant. Billions of years ago, the Milky Way had another neighbor, M32p, which was the third largest galaxy in the group. Two billion years ago, Andromeda swallowed M32p. This could mean that we may be on the Andromeda menu one day – if we do not get there first.

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