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The Milky Way Had a Big Sibling Long Ago And Andromeda Ate It
Space.com ^ | 7/23/18 | Mike Wall

Posted on 07/23/2018 6:57:35 PM PDT by LibWhacker

The Milky Way had a previously unknown big sibling that was torn apart by the neighboring Andromeda galaxy long ago, a new study suggests.

Andromeda and the Milky Way are the two largest members of the Local Group, a collection of more than 50 galaxies packed into a dumbbell-shaped region of space about 10 million light-years across. Andromeda was not kind to the onetime third-biggest member of this family, devouring it about 2 billion years ago, according to the new research.

"Astronomers have been studying the Local Group — the Milky Way, Andromeda and their companions — for so long," study co-author Eric Bell, a professor of astronomy at the University of Michigan (UM), said in a statement. "It was shocking to realize that the Milky Way had a large sibling, and we never knew about it." [When Galaxies Collide: Photos of Great Galactic Crashes]

Andromeda, also known as M31, is a prolific cannibal; the huge spiral galaxy is thought to have shredded hundreds of its smaller kin over the eons. The number and complexity of these mergers makes it tough to tease out the details of any particular one — but Bell and study lead author Richard D’Souza, a postdoctoral researcher at UM, were able to do just that.

Using computer simulations, the duo determined that most of the stars in the faint outer reaches of Andromeda's "halo" — the roughly spherical region surrounding the galaxy's disk — came from a single smashup.

"It was a 'Eureka' moment," D'Souza said in the same statement. "We realized we could use this information of Andromeda's outer stellar halo to infer the properties of the largest of these shredded galaxies."

Further modeling work allowed them to date the merger to about 2 billion years ago, and to reconstruct some basic details of that long-dead galaxy. M32p, as the researchers call it, was likely at least 20 times bigger than any galaxy that the Milky Way has ever merged with, the new results indicate.

And M32p is apparently not completely gone. D'Souza and Bell think that an odd satellite galaxy of Andromeda called M32 is the lost galaxy's corpse — the bones left behind after the big, nasty spiral munched off M32p's meat.

"M32 is a weirdo," Bell said. "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."

The timing of the merger matches up as well. Another research team independently determined earlier this year that Andromeda likely underwent a big merger, and a concomitant surge of star formation, between 1.8 billion and 3 billion years ago.

The new study, which was published online today (July 23) in the journal Nature Astronomy, should help scientists better understand the evolution and effects of galaxy mergers, D'Souza and Bell said.

For example, it has long been assumed that huge crashes destroy the disks of spiral galaxies, turning these gorgeous objects into rather drab elliptical galaxies. But Andromeda has retained its spiral disk, suggesting that the conventional wisdom does not always hold.

As dramatic as the Andromeda-M32p collision likely was, something much bigger is on the horizon. About 4 billion years from now, the Milky Way and Andromeda will come together in an epic crash that will shake up the Local Group. The merger will spark some pretty impressive star-formation fireworks in Earth's night sky, if anyone's still around to see it.


TOPICS: Astronomy; Science
KEYWORDS: andromeda; catastrophism; fauxiantrolls; m32; milky; sibling; way
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1 posted on 07/23/2018 6:57:35 PM PDT by LibWhacker
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To: LibWhacker

.
The whole mess was created 6000 years ago.

These people have hyperactive immaginations.
.


2 posted on 07/23/2018 7:01:43 PM PDT by editor-surveyor (Freepers: Not as smart as I'd hoped they'd be)
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To: LibWhacker

Andromeda Galaxy is about 3 billion years from colliding with the Milky Way Galaxy. I am pretty sure democRATs have sold us out.


3 posted on 07/23/2018 7:07:42 PM PDT by MtnClimber (For photos of Colorado scenery and wildlife, click on my screen name for my FR home page.)
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To: MtnClimber

After three billion years, a Milky Way would begin to look tasty.


4 posted on 07/23/2018 7:09:27 PM PDT by Larry Lucido
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To: LibWhacker
. Andromeda was not kind to the onetime third-biggest member of this family, devouring it about 2 billion years ago,

Something tells me they have Andromeda wrong. I think she took the galaxy in to protect and care for it. After all, the Universe can be a very dangerous place to be alone in.

5 posted on 07/23/2018 7:09:50 PM PDT by ETL (Obama-Hillary, REAL Russia collusion! Uranium-One Deal, Missile Defense, Iran Deal, Nukes: Click ETL)
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To: LibWhacker

Bad Dog....


6 posted on 07/23/2018 7:10:21 PM PDT by Paladin2 (no spelchek, no problem...)
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To: MtnClimber

Not sure a Milky Way would stay fresh that long, though.


7 posted on 07/23/2018 7:10:27 PM PDT by Larry Lucido
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To: Larry Lucido
Not sure a Milky Way would stay fresh that long, though.

It's vacuum packed, should be okay.

8 posted on 07/23/2018 7:14:44 PM PDT by Covenantor (Men are ruled...by liars who refuse them news, and by fools who cannot govern. " Chesterton)
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To: LibWhacker

9 posted on 07/23/2018 7:18:06 PM PDT by DannyTN
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To: SunkenCiv

*ping*


10 posted on 07/23/2018 7:23:46 PM PDT by fieldmarshaldj ("It's Slappin' Time !")
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To: Larry Lucido
After three billion years, a Milky Way would begin to look tasty.

I prefer Snickers, myself.

11 posted on 07/23/2018 7:24:48 PM PDT by dfwgator (Endut! Hoch Hech!)
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To: DannyTN
Re: Say, is that a Milky Way?

The bite size variety. The kind we pass out on Halloween.


12 posted on 07/23/2018 7:25:16 PM PDT by ETL (Obama-Hillary, REAL Russia collusion! Uranium-One Deal, Missile Defense, Iran Deal, Nukes: Click ETL)
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To: LibWhacker
Andromeda was not kind to the onetime third-biggest member of this family, devouring it about 2 billion years ago, according to ithe new research.

Amazing how much silly, melodramatic phrasing has gone into a straightforward story about a billions-year old merger between two groups of stars. The actual facts are interesting enough without all of the "Buffy the Vampire Slayer"-style narration.
13 posted on 07/23/2018 7:33:49 PM PDT by AnotherUnixGeek
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To: LibWhacker

That’s nothing - https://m.youtube.com/watch?v=tvjV_wUQGnU


14 posted on 07/23/2018 7:45:38 PM PDT by Noumenon (When all liberals have is a hammer, every problem is a nail in YOUR coffin.)
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To: LibWhacker

And we know this how?


15 posted on 07/23/2018 8:00:48 PM PDT by Not A Snowbird (I work for DHS. Not ashamed of it.)
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To: Not A Snowbird

Scientific faith. Because they cant prove it.

There’s a massive amount of “science” that is taken solely on “faith”.

Most of them are just as religious as the religious folks they despise, its just faith in a different thing. Of course their assumptions are just that. And nevermind the stuff they write papers on and base careers on, get disproven and all the stuff they demanded we believe because “its science and proven” all get dumped out.


16 posted on 07/23/2018 8:11:10 PM PDT by Secret Agent Man ( Gone Galt; Not averse to Going Bronson.)
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To: AnotherUnixGeek

I agree. I once posted a thread about some scientists who were planning to send a probe to study the dirty rings around Uranus, and you wouldn’t believe what that thread turned into!


17 posted on 07/23/2018 8:15:03 PM PDT by LibWhacker
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To: LibWhacker

All this and I’m still trying to figure out why Dr. Smith wasn’t murdered by the Robinson’s for all the chaos and damage he caused them.


18 posted on 07/23/2018 8:18:42 PM PDT by Kickass Conservative (The way Liberals carry on about Deportation, you would think "Mexico" was Spanish for "Auschwitz".)
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To: Not A Snowbird

It helps to read the article.


19 posted on 07/23/2018 8:19:09 PM PDT by LibWhacker
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To: LibWhacker

I did.


20 posted on 07/23/2018 8:35:17 PM PDT by Not A Snowbird (I work for DHS. Not ashamed of it.)
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