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https://phys.org/news/2024-01-stars-slowly-milky-edge-galaxy.html
By clocking the speed of stars throughout the Milky Way galaxy, MIT physicists have found that stars further out in the galactic disk are traveling more slowly than expected compared to stars that are closer to the galaxy's center. The findings raise a surprising possibility: The Milky Way's gravitational core may be lighter in mass, and contain less dark matter, than previously thought.
The new results are based on the team's analysis of data taken by the Gaia and APOGEE instruments. Gaia is an orbiting space telescope that tracks the precise location, distance, and motion of more than 1 billion stars throughout the Milky Way galaxy, while APOGEE is a ground-based survey.
The physicists analyzed Gaia's measurements of more than 33,000 stars, including some of the farthest stars in the galaxy, and determined each star's "circular velocity," or how fast a star is circling in the galactic disk, given the star's distance from the galaxy's center.
[...] The team translated the new rotation curve into a distribution of dark matter that could explain the outer stars' slow-down, and found the resulting map produced a lighter galactic core than expected. That is, the center of the Milky Way may be less dense, with less dark matter, than scientists have thought.
(Score: 4, Funny) by Gaaark on Wednesday January 31 2024, @11:35PM (7 children)
It's got no dark matter, which proves dark matter exists!
What? It HAS dark matter? PROOF that dark matter exists!
It has LESS dark matter than we thought! Proof dark matter exists!
Dark matter MUST exist because GR begs for it, which means DM MUST exist...because GR NEEDS it which means it MUST exist......
Just wish we could find it. :P
--- Please remind me if I haven't been civil to you: I'm channeling MDC. I have always been here. ---Gaaark 2.0 --
(Score: 1) by khallow on Thursday February 01 2024, @03:00AM
(Score: 4, Interesting) by Thexalon on Thursday February 01 2024, @04:29AM (2 children)
Any cosmologist worth their degree will tell you that dark matter is very much a placeholder, and they have little clue what it might be, they just know it makes all the equations work properly again.
My own completely speculative and damn-near-impossible-to-prove conjecture on this: Stuff that falls into a black hole gets accelerated so fast it ends up as tachyons, that wonderful hypothetical FTL matter. That stuff is theorized to behave very much like matter, except moving the other way through time, and since matter creates gravity that moves at C, it stands to reason that tachyons would be both unobservable with current equipment (because they're moving too fast), and also create gravity that moves at C. Oh, and since the way FTL makes any sense at all is that time is reversed, all that stuff gets to slide backwards in time to the Big Bang, where it creates what we would observe as a white hole, and that's where all the normal matter we can observe came from.
"Think of how stupid the average person is. Then realize half of 'em are stupider than that." - George Carlin
(Score: 1, Interesting) by Anonymous Coward on Thursday February 01 2024, @07:24AM (1 child)
That theory would actually work better to explain dark energy. Time-reversed gravity would push things apart.
(Score: 2) by Thexalon on Thursday February 01 2024, @12:14PM
I used the word "conjecture" for a reason: The idea definitely doesn't rise to the level of "theory" yet, not even close.
"Think of how stupid the average person is. Then realize half of 'em are stupider than that." - George Carlin
(Score: 2) by tangomargarine on Thursday February 01 2024, @06:47AM (2 children)
I wonder if dark matter will be proved to not exist in my lifetime, like Einstein and that extra variable to make the universe static, or the search for Planet X because Neptune's density was different than expected so the orbital discrepancy worked itself out.
That 80+% of the universe is somehow "invisible" is just such a wild idea.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by crafoo on Thursday February 01 2024, @02:52PM
I don't know, I don't think it's all that wild at all. It's more likely that dark matter is real than not. We've only experienced the universe from a single physical point and in a timespan that is so short it is irrelevant in terms of astrophysics. We are instinctually wired to believe that the E&M spectrum is fundamentally prime as it is our primary sensory input into our brain.
Maybe there is something else in the universe going on and it only just barely interacts with any of the physics we know through gravitational changes.
What ever dark matter is or isn't, it is not worth arguing about, discouraging other theories, or trying to tell someone they are wrong about it. No one knows or has the authority at this point to say one way or another. The best course is, as always, to pick an avenue and provide positive work in that direction to help prove or eliminate that particular branch. All of these discussion about it at of now are absolutely worthless. It's very much similar to Catholics and Protestants arguing.
(Score: 2) by Freeman on Thursday February 01 2024, @07:34PM
In the event that as someone posted already that including dark matter makes everything else work in general relativity. Then, it's quite plausible that the "whatever is missing" which they're calling dark matter is something. I'm also of the opinion that there's more Nobel Prizes in Physics to win.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"