May 20, 20196 yr Quote There's a "dark impactor" blasting holes in our galaxy. We can't see it. It might not be made of normal matter. Our telescopes haven't directly detected it. But it sure seems like it's out there. "It's a dense bullet of something," said Ana Bonaca, a researcher at the Harvard-Smithsonian Center for Astrophysics, who discovered evidence for the impactor. Bonaca's evidence for the dark impactor, which she presented April 15 at the conference of the American Physical Society in Denver, is a series of holes in 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. ... So far, Bonaca's discovery is one of a kind, so new that it hasn't yet been published in a peer-reviewed journal (though it was met appreciatively by the crowd of physicists at the prestigious conference). To pull it off, she relied on data from the Gaia mission, an European Space Agency program to map billions of stars in our galaxy and their movements across the sky. It formed the best existing catalog of the stars that seem to be part of GD-1. Bonaca buttressed that data with observations from the Multi Mirror Telescope in Arizona, which showed which stars were moving toward Earth, and which were moving away. That helped distinguish between stars that were really moving with GD-1, and those that just sat next to it in Earth's sky. That effort produced the most precise image ever of GD-1, which revealed the second gap, the spur, and a previously unseen region of the stellar stream. ... https://www.livescience.com/65483-dark-impactor-could-be-dark-matter.html
May 20, 20196 yr 6 hours ago, bernorange said: That effort produced the most precise image ever of GD-1, which revealed the second gap, the spur, and a previously unseen region of the stellar stream. Spoiler
May 24, 20196 yr Author I apologize for the thread title fail, but "Apparently the GD-1 Stellar Stream got Falcon Punched" doesn't have the same impact. Intergalactic pool. Rack'em!
May 24, 20196 yr So...Your mom enjoyed a dense bullet of something with a dark impacting or whatever.
June 5, 20196 yr On 5/20/2019 at 8:04 AM, bernorange said: so new that it hasn't yet been published in a peer-reviewed journal aka, it's not yet proper science call me when it's legit
June 5, 20196 yr 12 minutes ago, Rimbo said: aka, it's not yet proper science call me when it's legit Your mom isn't proper science and still likes a good dark impactor.
June 5, 20196 yr 47 minutes ago, ztejas said: Your mom isn't proper science and still likes a good dark impactor. You will speak of your biological grandmother with more respect, boy Edited June 5, 20196 yr by Rimbo
June 6, 20196 yr Author Searched around a bit and found an article from almost a year ago that has a handy graphic (can't embed though - someone can screenshot if they want to): https://www.sciencemag.org/news/2018/10/streams-stars-reveal-galaxy-s-violent-history-and-perhaps-its-unseen-dark-matter
January 10, 20205 yr Author Damn, Milky Way, you need to learn how to bob and weave... Quote An enormous wave has been discovered in the Milky Way that may have formed as a result of a collision with a massive mystery object—potentially a clump of dark matter—scientists have said. The "Radcliffe wave" was discovered using data from the European Space Agency's Gaia satellite. It had previously gone unnoticed because of its extreme size and our proximity to it. From Earth, the wave covers half the sky, making it difficult to see the whole structure. Details of the discovery are published in Nature. ... https://www.newsweek.com/milky-way-huge-wave-collision-1480799?utm_term=Autofeed&utm_medium=Social&utm_source=Facebook
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