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from the a-proton-and-a-neutron-walk-into-a-black-hole dept.
In a presentation given on April 15th at the American Physical Society in Denver, Researcher Ana Bonaca of the Harvard-Smithsonian Center for Astrophysics presented evidence for a "dark impactor" tearing through our galaxy's longest stellar stream - GD-1.
Stellar streams are lines of stars moving together across galaxies, often originating in smaller blobs of stars that collided with the galaxy in question. The stars in GD-1, remnants of a "globular cluster" that plunged into the Milky Way a long time ago, are stretched out in a long line across our sky.
Under normal conditions, the stream should be more or less a single line, stretched out by our galaxy's gravity, she said in her presentation. Astronomers would expect a single gap in the stream, at the point where the original globular cluster was before its stars drifted away in two directions. But Bonaca showed that GD-1 has a second gap. And that gap has a ragged edge — a region Bonaca called GD-1's "spur" — as if something huge plunged through the stream not long ago, dragging stars in its wake with its enormous gravity. GD-1, it seems, was hit with that unseen bullet
The impactor doesn't match the path of any luminous object according to Bonica. Additionally it is far more massive than a star, approximately a million times more massive than the sun, and between 10 and 20 parsecs across.
That leaves limited possibilities - possibly a black hole, but this would be a black hole on-par with the supermassive black holes found at the center of galaxies. Additionally
we'd expect to see some sign of it, like flares or radiation from its accretion disk. And most large galaxies seem to have just a single supermassive black hole at their center.
This leaves an intriguing possibility. A dark matter object or structure.
With no giant, bright objects visible zipping away from GD-1, and no evidence for a hidden, second supermassive black hole in our galaxy, the only obvious option left is a big clump of dark matter. That doesn't mean the object is definitely, 100%, absolutely made of dark matter, Bonaca said.
The findings are based on data obtained from the ESA Gaia mission.
Bonica's results were well received but have not yet been published in a peer reviewed journal.
(Score: 2) by The Mighty Buzzard on Saturday May 18 2019, @07:06PM (4 children)
That's not how science works. You don't go with a colossally shitty theory until you come up with a better one, you say "fuck if we know" until you can prove it one way or the other.
My rights don't end where your fear begins.
(Score: 0) by Anonymous Coward on Saturday May 18 2019, @09:34PM (3 children)
No one has stated that dark matter is the answer, just the best theory so far. Possibly a black hole, but as stated those usually leave some observable evidence. Since they did not state that it is definitively dark matter then this is exactly how science works. You make the best guesses possible and go from there.
Maybe schooling woulda been a good move for you, you really give yourself way too much credit.
(Score: 2) by The Mighty Buzzard on Sunday May 19 2019, @09:59AM (2 children)
This would be a valid assertion if the dark matter hypothesis held any kind of water to begin with. Currently it does not though. At this point it's no more deserving of inclusion in the list than a Magic Fairy Dust hypothesis. "Huh, our math's coming out horribly and unpredictably wrong on galactic and larger scales," does not mean you go adding Magic Fairy Dust until it comes out right then claim the existence of Magic Fairy Dust is decent working theory because adding enough to unfuck your math unfucked your math.
My rights don't end where your fear begins.
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @03:38PM (1 child)
You should ask the nearest grandma to bake you some humble pie. Magical fairy dust is worth a lot more than your useless complaining.
I think DM is wrong and our theory is just incomplete, but unlike you I don't toss out possibilities because of a massively over inflated ego. You are a pox on rational discussion.
(Score: 2) by The Mighty Buzzard on Sunday May 19 2019, @10:56PM
Show me the tested predictions the DM hypothesis has made possible -- without having to massage the math to fit -- or it is Magical Fairy Dust. It may or may not be true Magical Fairy Dust but it's utterly and completely unproven in any way at this point. It is a Wild-Assed Guess.
My rights don't end where your fear begins.