Black Holes May Be Swallowing Invisible Matter That Slows the Movement of Stars...
source link: https://science.slashdot.org/story/23/03/28/0036248/black-holes-may-be-swallowing-invisible-matter-that-slows-the-movement-of-stars
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.
Black Holes May Be Swallowing Invisible Matter That Slows the Movement of Stars
Please create an account to participate in the Slashdot moderation system
binspamdupenotthebestofftopicslownewsdaystalestupid freshfunnyinsightfulinterestingmaybe offtopicflamebaittrollredundantoverrated insightfulinterestinginformativefunnyunderrated descriptive typodupeerror
Sign up for the Slashdot newsletter! or check out the new Slashdot job board to browse remote jobs or jobs in your area.
The team watched as the orbits of two stars decayed, or slightly slowed, by about 1 millisecond per year while moving around their companion black holes, designated A0620-00 and XTE J1118+480. The team concluded that the slow-down was the result of dark matter surrounding the black holes which generated significant friction and a drag on the stars as they whipped around their high-mass partners.
Using computer simulations of the black hole systems, the team applied a widely held model in cosmology called the dark matter dynamical friction model, which predicts a specific loss of momentum on objects interacting gravitationally with dark matter. The simulations revealed that the observed rates of orbital decay matched the predictions of the friction model. The observed rate of orbital decay is around 50 times greater than the theoretical estimation of about 0.02 milliseconds of orbital decay per year for binary systems lacking dark matter. The study has been published in The Astrophysical Journal Letters.
-
›
Dumb question, I know, but.... what the heck is dark matter anyway? It obviously has mass or it would not be interacting with visible matter gravitationally and it does not interact with light. Will a space craft be smashed to bits when it cruises into dark matter at half the speed of light? Do we have to worry about dark matter asteroids smashing into the earth? Are there dark matter elements that we should add to the periodic table? <sarcasm> Can we build invisible tanks from dark matter? Invisible-
Dumb question, I know, but.... what the heck is dark matter anyway?
Nobody knows. The first person to figure it out will get a trip to Stockholm.
But we know what it isn't. It isn't any form of baryonic matter, and it isn't micro-blackholes.
Will a spacecraft be smashed to bits when it cruises into dark matter
No. Dark matter does not interact with "normal" matter.
Do we have to worry about dark matter asteroids smashing into the earth?
No. Dark matter doesn't clump into asteroids or anything else.
Are there dark matter elements that we should add to the periodic table?
No. It makes no sense to talk about "elements" of non-baryonic matter.
-
"No. Dark matter does not interact with "normal" matter."
If the article is correct, and I do not know if it is, then dark matter must at least interact with gravitational fields produced by ordinary matter. So that sense it does interact with normal matter.
-
Yes. It is wrong to say it doesn't interact with bryonic matter. It interacts only gravitationally. So the OP's question is basically, will a space craft be smashed only because of gravitaional energy? My guess is probably right and it is - no, things are "smashed" because molecules come close enough that they start repelling each other, converting the kinetic energy o the molecules into bond energy which above a threshold causes the bonds to break (at lower speeds, the bond energy is not enough, so it is d
-
Probably correct but there is A family of models for dark matter that supposed primordial black holes left over from the Big Bang. We know they can’t be too small or they would have evaporated from Hawking radiation or been observed and we know they can’t be as massive as the sun or we would see the gravitational lensing and interactions with objects. But there is a sweet spot of low mass, where they would be Very hard to detect. Luckily our solar system came with several large detectors that
-
-
-
We barely know what a black hole is from millions of light years away, so perhaps we don't assume what "isn't". We barely know anything about the universe, with even the "known" universe being a tiny fraction of reality. Not surprising, since we're almost as clueless about what lies in the deepest parts of our own oceans.
What we DO know, is the definition of a "theory". We also know, humans can be wrong. Including astrophysicists, astrologists, and cosmologists.
-
The closest BH is 1600 ly from Earth.
-
and from this relatively short distance, a black hole may simply be a planetary body with an escape velocity exceeding that of a photon.
-
That we know of.
-
And our achievements have traveled less than 30 light minutes away so far, which took decades to achieve.
Pretty sad when order-of-magnitude sized errors don't even matter.
-
According to Nature, someone has recently been able to create artificial black holes in the lab.
-
-
-
We know it is not baryonic matter but small, primordial black holes have not been ruled out yet. While there is no known mechanism to produce the latter but it is going to be a while before LIGO is sensitive enough to rule them out - or detect them via their collisions.
Yes, it does interact with matter at least via gravity because we see it through its gravitational effects on matter. It does not interact with matter through the electromagnetic force though otherwise it would interact with light and it wo
-
-
It's a particle cosmologists theorized must exist because without it a few observations don't match what the math predicts. Galaxy rotation speed, for example. If it exists, it interacts only gravitationally, what few attempts there have been to detect it directly showed no result. Ramming into dark matter would feel like nothing.
Particulate dark matter as a theory doesn't explain everything, i.e. it is not universally considered to be the final answer in cosmology. Some competing hypotheses are superfluid -
It's the astrophysicists' version of a Keleven.
-
The community prefers to give it a better name, given all the funding.
"Fucking clueless" doesn't bring in the dollars no matter how good you dance around a black hole.
-
It is a made up astronomer fantasy material required to make their equations work.
So, either there is this bizarro stuff filling most of the universe which a bunch of folks are making their careers on.
Their equations are wrong.
You decide.
-
We need Richard Feynman back. We could all meet in his favorite strip club and get this stuff all figured out. https://www.tsbmag.com/2014/02... [tsbmag.com]
-
-
Not dumb. Dark matter is a placeholder name for "Something is happening here, and we're not sure what it is."
It is unfortunate that it was named dark matter, in the same way that a scientific theory is named. Kinda confusing.
The public conflates "Theory" with a WAG - or Wild Ass Guess. In science the hypothesis is more like the WAG, and a theory is when the WAG's are shown to be pretty much correct.
At least that's my theory! 8^)
-
-
I'm astonished, and very sceptical, of their ability to distinguish orbital decay of 1ms per year versus predictions of 0.02ms per year, at a distance of over 3,000 light years.
-
I've seen Dave click his stopwatch so fast it's amazing.
Dave could do it.
-
I am not skeptical because that is 50x the difference.
-
Whoosh!
-
-
What does distance from an object have to do with periodic timing?
-
-
" the dark matter dynamical friction model, which predicts a specific loss of momentum on objects interacting gravitationally with dark matter."
What about the stars that orbit too fast for F=ma predictions? Isn't that a case of a specific gain in momentum on objects interacting gravitationally with dark matter?
-
Well, if you assume the only gravitational force is from normal matter then the f=ma prediction fails but if you assume a properly shaped cloud of dark matter, or halo, then f=ma works because there is an F that satisfies the math and correlates with reality for any m or a. The key is to have it be descriptive of reality with measurements only ever validating the model and for this dark matter halos seem to be on top so far. The dark matter halo won’t necessarily have the same speed or density as
-
-
I'm thinking that any future ships sent to study this should be completely black [fandom.com] on the outside as well as...
... the interior of the ship was completely black. There were black controls labelled in black, on a black background, with a little light that lit up black, which made it difficult to control the ship. The ceiling and walls of the swaying cabin were also black, as well as the seats, control panel, the instruments and the little screws that held them in place. The thin tufted nylon floor covering was black, and when a corner of the foam underlay was lifted up that was also discovered to be was black.
To compliment the black holes and dark matter.
-
-
... hitch hiker's, restaurant at the end of the universe. That was galactic level rock star Hot Black (sp?)'s ship.
It's been half of forever since I read them. I should reread the series and you should have a first go.
-
-
-
...nice try! Now find a more realistic explanation, please.
-
MOND is the real answer. We don't understand gravity in extreme environments or at galactic distances. For decades we've been waiting. First for the TOE. Then the GUT. Now it's all about the MOND. After that it's onto gravity generators and household appliances that dilate time so you can have a forever cupboard wherein things age really slowly.
-
Can I have instant toast and hot tea? I hate trying to time it so they're both ready together.
-
-
-
I thought dark matter didn't interact with normal matter except gravitationally? How could it create "drag"?
-
How could it create "drag"?
By gravitation. It's called Chandrasekhar friction, or Dynamical Friction [wikipedia.org].
-
Don't worry about that - Republicans are working hard to eliminate drag.
-
-
It says: "The team watched as the orbits of two stars decayed, or slightly slowed, by about 1 millisecond per year".
However, this is not how celestial mechanics works. If an orbiting body loses some total energy due to e.g. friction, it transfers to a lower orbit. And in the lower orbit, the period is lower and the orbital speed is higher. In other words, the orbiting body subject to friction, in fact, accelerates due to the reduction of the potential energy in the gravitational field over-compensating the
Recommend
About Joyk
Aggregate valuable and interesting links.
Joyk means Joy of geeK