The Milky Way Has a Gigantic Skeleton in Its Closet

Scientists have identified the topic of a galaxy that fell into the Milky Way about 10 billion years ago in what was likely the last major overhaul to our home galaxy during its development.

That's the conclusion of new research based on 2 billion measurements of the Milky Way are moving stars. Those measures let scientists identify about 33,000 stars in our galaxy but were born elsewhere.

"The Milky Way is a cannibal." "It has been a long time ago in the past," Kathryn Johnston, an astronomer at Columbia University in New York. involved in the new research, told Space.com. "This is a police investigation – this one in particular, because it's not a galaxy that we can see today, it's a dead galaxy, so it makes it kind of fun." [Photos: Gaia Spacecraft to Map Milky Way Galaxy]

The research is possible because of stars contain a fingerprint of spells of their origin. "When you look at how stars move, they actually retain their motions [a] "Amina Helmi, an astronomer at the University of Groningen in the Netherlands, told Space.com.

Helmi and her colleagues drew Gaia, which is mapping the location of 1 billion stars in the Milky Way with unprecedented precision. The team identified a set of about 33,000 of those stars that are moving in a completely different way compared to the bulk of the Milky Way.

The team also studied the chemistry of nearly 600 stars using ground-based telescope data, which confirmed that these stars had come from somewhere beyond the Milky Way. And the sheer amount of data at the team's fingertips let the scientists estimate the size and age of the colliding galaxy.

Given those numbers, the researchers said, "The size of the modern Milky Way. That means that this is hardly a galactic collision scientist has pinpointed, it's a comparatively huge one, the scientists said.

Helmi and her colleagues named galaxy Gaia-Enceladus to honor the instrument that gathered the crucial data Helmi used to address a question that has been nagging her for two decades. In Greek myths, Enceladus is the giant son of Gaia and Sicily, causing seismic activity – and the galactic burial would have caused a lot of upheaval well.

The team's simulations suggest that the collision be divided into two. The collision is one of the reasons why it is so important to have a thick film, Helmi said, yet Johnston said there is more work to be done before scientists can fully flesh out how that might have worked.

But it's clear that the collision played a significant role in making our galaxy what it is today. For the United States of America snacking their way through a Halloween haul, consider the injection of caramel that turns into a simple 3 Musketeers bar into the cosmic candy we know and love called Milky Way. [Ghouls and Gourds! Awesome Photos from NASA JPL’s 2018 Pumpkin-Carving Contest]

There's lots to love about knowing about our own home-sweet-home galaxy cam to be, Johnston said. But for her, the implications of research like this stretch far beyond the Milky Way, she said. She compared studying to the universe to photographing 1,000 humans, where all you can tell Studies like this are a detailed portrait of one individual from that mass.

"We're actually not seeing the freckles on the faces – we're seeing the flecks in the eyes," Johnston said. "It's like seeing the inner workings of a person."

The research is described in a paper published today (Oct. 31) in the journal Nature.

Meghan Bartels at [email protected] or follow her @meghanbartels. Follow us @Spacedotcom and Facebook. Original article on Space.com.