The Milky Way Had A Sister Galaxy, But The Andromeda Galaxy Ate It

Wednesday, 25 July 2018 - 10:26AM
Astronomy
Solar System
Wednesday, 25 July 2018 - 10:26AM
The Milky Way Had A Sister Galaxy, But The Andromeda Galaxy Ate It
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Image Credit: Pixabay
If renderings showed just how brutal things actually are in space, museums would have to issue warnings for visitors under a certain age. Astronomers recently witnessed for the first time what they believe to be a young star snacking on planets, but that event is certainly not an isolated incident and it is not exclusive to hungry stars. According to a team of scientists at the University of Michigan, the Milky Way galaxy would probably still have a sister galaxy had she not been ripped apart and consumed by the Andromeda Galaxy over 2 billion years ago.

What is left of the galaxy, named M32p, is a "nearly invisible halo" of stars that is larger than all of Andromeda. Scientists already knew that Andromeda was a savage galaxy responsible for the destruction of hundreds of other galaxies, but by using new computer simulations, the U of M team (Richard D'Souza and Eric Bell) were able to determine that most of stars in the halo around the cannibal are from one large galaxy. "It was a 'eureka' moment," said D'Souza in a statement.

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We realized we could use this information of Andromeda's outer stellar halo to infer the properties of the largest of these shredded galaxies.
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M32p is estimated to have been 20 times larger than any galaxy that merged with our own over several millennia. In terms of size, it would have ranked third in the Local Group, right behind the Milky Way and its murderer, Andromeda. According to D'Souza and Bell, the galaxy may finally explain the existence of M32, which is a satellite galaxy of Andromeda. The theory is that when Andromeda destroyed M32p, it's center became the unique M32. "M32 is a weirdo," said Bell. "While it looks like a compact example of an old, elliptical galaxy, it actually has lots of young stars. It's one of the most compact galaxies in the universe. There isn't another galaxy like it."

NASA's Hubble team confirmed years ago that the Milky Way and Andromeda are going to collide, but that won't happen for another 4 billion years. Even then, the Earth will probably survive...just without our Sun. Never too early to get your heat lamps and flashlights ready.


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