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(Big Think)   Dark matter gravitates just as normal matter does, but only normal matter can make black holes. Here's why   (bigthink.com) divider line
    More: Interesting, General relativity, normal matter, dark matter, Dark matter, black holes, Physical cosmology, massive black holes, event horizon forms  
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1131 clicks; posted to STEM » on 12 Nov 2021 at 3:20 PM (27 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



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2021-11-12 2:44:12 PM  
I enjoyed that article, well written and deserving of the interesting tag 👍
 
TWX
2021-11-12 3:26:57 PM  
Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.
 
2021-11-12 3:38:03 PM  
And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED
 
2021-11-12 3:52:05 PM  

lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED


This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.
 
2021-11-12 3:54:06 PM  

TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.


PBS Space Time has a good video about that:

What If (Tiny) Black Holes Are Everywhere?
Youtube srVKjWn26AQ
 
2021-11-12 4:05:32 PM  
Because yo momma isn't made of dark matter.
 
2021-11-12 4:15:43 PM  

lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED


It should be called "matter of color".
 
2021-11-12 4:24:30 PM  
Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?
 
TWX
2021-11-12 4:34:13 PM  

lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED


I propose the unit be the Gravito, with Graviti as plural.

Pronounced "grah-VEE-toh" and "grah-VEE-tee"
 
2021-11-12 4:39:53 PM  

Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?


In TFA it said dark matter can fall into black holes, it just can't make one by itself.
 
2021-11-12 4:41:07 PM  

lifeslammer: And here I thought


We know how that ends
 
2021-11-12 4:41:52 PM  

sxacho: Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?

In TFA it said dark matter can fall into black holes, it just can't make one by itself.


Correct- but why can't it make its way out again?  The more I think about it the mass thing has to be correct, since it would be the same for a particle of normal matter even in the absence of some way to lose energy
 
2021-11-12 4:45:23 PM  

Tranquil Hegemony: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.


There was a hole on the particle chart for the Higgs Bosun.  There is no spot for the Dark Matter particle. It's very doubtful Dark Matter is a particle. Same for Dark Energy.
 
2021-11-12 4:49:11 PM  

TedCruz'sCrazyDad: Tranquil Hegemony: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.

There was a hole on the particle chart for the Higgs Bosun.  There is no spot for the Dark Matter particle. It's very doubtful Dark Matter is a particle. Same for Dark Energy.


The chart is just something to help people visualize the different particles. There was no "hole" for the Higgs. When the Higgs was confirmed they added it to the chart.

Just like with neutrinos. They got a whole row. And before it was confirmed via experiment, it was just math.
 
2021-11-12 4:53:10 PM  

TWX: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

I propose the unit be the Gravito, with Graviti as plural.

Pronounced "grah-VEE-toh" and "grah-VEE-tee"


the gravitons and graviolis
Youtube qs019BL76DU
 
2021-11-12 4:56:26 PM  

Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?


I'm just a layman. So I don't know, of course.

Light doesn't have frictional losses and it can't escape.  The escaping comes from the curvature of space, not the energy of any particle.  If the nearest point of approach of that hyperbolic orbit lies within the event horizon, it means it can't escape solely due to the spacetime curvature there.  Whether it converts energy to mass or velocity would be irrelevant.

I think one of the points of the article is just that an event horizon has a certain "cross-section" for dark matter that is way, way smaller than that for normal matter.  The way I'm thinking of it would be that it's much easier for normal matter to wind up in, say, the accretion disk and eventually get sucked in than for dark matter on a random orbit to score a "direct hit" on the event horizon itself.
 
2021-11-12 5:01:00 PM  
Glockenspiel Hero: ... an apohole ...

Apohole is the name of my incel-themed emo band.
 
2021-11-12 6:10:57 PM  

Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?


You mean Perihole.  Periapsis is closest point in the orbit, Apoapsis is farthest point in the orbit, so a hyperbolic orbit only has a periapsis.

Nothing loses energy by entering a black hole's event horizon.  Energy has nothing to do with it.  The shape of spacetime beyond the event horizon is such that all roads lead to the singularity regardless of which direction you move in.
 
2021-11-12 6:24:47 PM  
Is it that they can't have black masses?

Black sabbath-War Pigs (lyrics)
Youtube uJ6QHfZwTSw
 
2021-11-12 6:31:48 PM  
It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.
 
2021-11-12 6:42:12 PM  

Nurglitch: It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.


Statistically, baryonic matter is the weird one.

Electromagnetic force is crazy.
 
2021-11-12 6:43:27 PM  
Dark matter only interacts with ordinary matter through gravity (as far as we know).  Is there a reason dark matter can't interact with other dark matter via forces that don't interact with ordinary matter and hence are currently undetectable?
 
2021-11-12 7:00:21 PM  

Raoul Eaton: Dark matter only interacts with ordinary matter through gravity (as far as we know).  Is there a reason dark matter can't interact with other dark matter via forces that don't interact with ordinary matter and hence are currently undetectable?


It's entirely possible, but the anomalous observations that DM theory exists to explain require it to be diffuse rather than clumpy; so probably not.
 
2021-11-12 7:01:09 PM  

Nurglitch: It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.


Since it can't collide with itself there's nothing to allow it to accumulate in one place.  You would basically have to have a chance situation where enough dark matter to form a black hole all reaches the same place at the same time.
 
2021-11-12 7:07:28 PM  

Nurglitch: It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.


It is not weird at all.  If you could get enough dark matter into a small enough volume, you would create a black hole. But that's the problem: you simple are not going to be able to get all that dark matter into such a small volume. Thus black holes will not be formed from dark matter.

Bonus: If you put enough light into a small enough volume, a black hole will be created. It is called a Kugelblitz black hole. That won't form naturally for obvious reasons, but theoretically it could be formed a technological means.
 
2021-11-12 7:07:39 PM  

LrdPhoenix: Nurglitch: It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.

Since it can't collide with itself there's nothing to allow it to accumulate in one place.  You would basically have to have a chance situation where enough dark matter to form a black hole all reaches the same place at the same time.


Given the size of the universe it seems like it wouldn't be tremendously rare.
 
2021-11-12 7:29:14 PM  

Nurglitch: It is kinda weird that dark matter wouldn't form a black hole via the direct collapse process. I mean, yeah, not baryonic matter, but still.


The issue is that, without other forces acting or a significant existing source of gravity, the dark matter would maintain its energy as it moves. A particle would fall toward the center of mass but would maintain its energy and pop back out the other side. This process would repeat without achieving the density necessary to form a black hole. Forming a black hole would require a pre-existing extreme density of dark matter.

Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?


Not a physicist, but a particle in a circular orbit at the event horizon must be moving at the speed of light. An elliptical orbit that goes even near the event horizon cannot exist because the particle cannot have the speed to escape even if it conserves all its energy. So yes, the increasing relativistic mass is where the extra energy goes.
 
2021-11-12 8:17:20 PM  

ccsears: I think one of the points of the article is just that an event horizon has a certain "cross-section" for dark matter that is way, way smaller than that for normal matter.  The way I'm thinking of it would be that it's much easier for normal matter to wind up in, say, the accretion disk and eventually get sucked in than for dark matter on a random orbit to score a "direct hit" on the event horizon itself.


Yup. The dark matter probably has to directly hit the black hole's event horizon. There is no dark matter accretion disk, because electromagnetic, friction, and other forces aren't dragging the dark matter down toward the hole.

If those other forces were affecting dark matter, those forces around a galaxy should have visible effects -- such as electromagnetic fields in a galaxy would attract/repel dark matter from certain areas, which would cause visible matter to get dragged around in certain ways which have not been seen. Thus, dark matter seems to not be affected by those forces and it remains diffuse.
 
2021-11-12 8:52:30 PM  
Because then they would be called dark holes, duh.
 
2021-11-12 8:59:05 PM  
FTA:When dark matter takes the plunge through the existing galaxy, it has no collisions, no friction, experiences no heating, no interactions with electromagnetic radiation, and no way to exchange energy or momentum with the other particles - both normal and dark particles - that exist within the galaxy.

For those of us who have studied ether, phlogiston, and quinessence, and for conpletion's sake also Descartes' whirlpool of liquid between stars, why should we give this idiotic peudoscience any more credence? It's not like the way negative numbers were invented to solve cubic equations. This description of dark matter is literally the same description as that of ether that held until Einstein's general theory of relativity.
 
2021-11-12 9:16:22 PM  

Bennie Crabtree: FTA:When dark matter takes the plunge through the existing galaxy, it has no collisions, no friction, experiences no heating, no interactions with electromagnetic radiation, and no way to exchange energy or momentum with the other particles - both normal and dark particles - that exist within the galaxy.

For those of us who have studied ether, phlogiston, and quinessence, and for conpletion's sake also Descartes' whirlpool of liquid between stars, why should we give this idiotic peudoscience any more credence? It's not like the way negative numbers were invented to solve cubic equations. This description of dark matter is literally the same description as that of ether that held until Einstein's general theory of relativity.


Because, as it turns out, neutrinos, the Higgs boson and top/bottom quarks exist; in other words, just because some physical phenomena invented to explain things without being directly observed turned out to be bullshiat it doesn't imply that all physical phenomena invented to explain things before being directly observed is bullshiat. Turns out when you see something you can't explain with the knowledge you have, you need to make up explanations so you can test and verify them instead of magically pulling the answer out of the farking... ether.

And for the record, that description is emphatically not a description of ether, and even if it was, saying it's "idiotic peudoscience" based on it is like saying horses are bullshiat because the description that they're "hoofed equine creatures featured heavily in culture" is literally the same description of unicorns.

//tldr you should try studying dark matter (or like, reading more than two paragraphs about it) before casting stones
 
2021-11-12 9:18:14 PM  

TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.


I'd call them Wiggum Holes.
Fark user imageView Full Size
 
2021-11-12 9:19:24 PM  

TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.


Or.... Considering it still hasn't been detected, Dark Matter is some made up BS to to fit a square peg into a round hole.

There is a model of the universe they accept and the math doesn't work based on observed motions of celestial bodies. Instead of rethinking the model, Dark Matter was invented out of whole cloth to make the previous model/ equations work.

I am a layperson when it comes to physics, but sometimes it's best to ask someone to take a second look to detect obvious BS. This is why I advocate having random idiot (like myself) with a juvenile's sense of humor on every executive board. This would stop things like the Facebook/ Meta debacle from happening.

If Dark Matter has been proven and detected, I would love to know.
 
2021-11-12 9:28:56 PM  

New Farkin User Name: Bennie Crabtree: FTA:When dark matter takes the plunge through the existing galaxy, it has no collisions, no friction, experiences no heating, no interactions with electromagnetic radiation, and no way to exchange energy or momentum with the other particles - both normal and dark particles - that exist within the galaxy.

For those of us who have studied ether, phlogiston, and quinessence, and for conpletion's sake also Descartes' whirlpool of liquid between stars, why should we give this idiotic peudoscience any more credence? It's not like the way negative numbers were invented to solve cubic equations. This description of dark matter is literally the same description as that of ether that held until Einstein's general theory of relativity.

Because, as it turns out, neutrinos, the Higgs boson and top/bottom quarks exist; in other words, just because some physical phenomena invented to explain things without being directly observed turned out to be bullshiat it doesn't imply that all physical phenomena invented to explain things before being directly observed is bullshiat. Turns out when you see something you can't explain with the knowledge you have, you need to make up explanations so you can test and verify them instead of magically pulling the answer out of the farking... ether.

And for the record, that description is emphatically not a description of ether, and even if it was, saying it's "idiotic peudoscience" based on it is like saying horses are bullshiat because the description that they're "hoofed equine creatures featured heavily in culture" is literally the same description of unicorns.

//tldr you should try studying dark matter (or like, reading more than two paragraphs about it) before casting stones


encrypted-tbn0.gstatic.comView Full Size
 
TWX
2021-11-12 9:29:38 PM  

baron von doodle: TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.

Or.... Considering it still hasn't been detected, Dark Matter is some made up BS to to fit a square peg into a round hole.

There is a model of the universe they accept and the math doesn't work based on observed motions of celestial bodies. Instead of rethinking the model, Dark Matter was invented out of whole cloth to make the previous model/ equations work.

I am a layperson when it comes to physics, but sometimes it's best to ask someone to take a second look to detect obvious BS. This is why I advocate having random idiot (like myself) with a juvenile's sense of humor on every executive board. This would stop things like the Facebook/ Meta debacle from happening.

If Dark Matter has been proven and detected, I would love to know.


I thought that it was pretty straightforward, the term itself is something of a placeholder describing a phenomenon that has not yet been itself thoroughly enough explained, based on observations made in the 1960s by Dr. Rubin that the amount of mass in galaxies was insufficient to account for their rotational behavior.

Mathematics and understanding of fundamental forces are what are described in TFA, basically under the presumption that Dark Matter only interacts through gravity, and that there are no other fundamental forces as yet undiscovered that it might act upon, then as point sources of gravity their movement can be described.  Perhaps Dark Matter is to gravity what the concept of the Magnetic Monopole is to electromagnetism.

Thing is you're making a fundamental mistake, you're assuming that your ignorance is as valuable as the education of those studying phenomena.  Clearly this is not so, and I don't see how it even relates to the corporate world as you assert.
 
2021-11-12 9:34:56 PM  
Dark matter is the holey spirit.
 
2021-11-12 9:54:09 PM  

lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED


We've got interesting circumstantial evidence of some of it's nature.

The classic example is the Bullet cluster, 2 massive collections (Superclusters) of galaxies that have collided and passed through one another.

The net mass can be charted in a few ways, and it's location is further past the collision point then the hot interstellar gas that was part of the collision.

This can, so far as we can ascertain, only be explained by the majority of the mass consisting of particles that don't interact with other matter save through gravity.

I have probably butchered this explanation, but the broad strokes are a compelling case for dark matter as a particle of some sort.
 
2021-11-12 9:59:19 PM  

Tranquil Hegemony: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.


No, it's exactly right. There are at least a half dozen highly plausible theories for the Dark Matter Hypothesis and most of them have nothing in common. This article was written by someone who assumes ONE of those theories (evidently, non-baryonic cold particles) must be the correct one. WIMPs would not interact the way the article describes, though, and neither would any of the modified gravity models.
 
2021-11-12 10:34:10 PM  
baron von doodle:

Or.... Considering it still hasn't been detected, Dark Matter is some made up BS to to fit a square peg into a round hole.

There is a model of the universe they accept and the math doesn't work based on observed motions of celestial bodies. Instead of rethinking the model, Dark Matter was invented out of whole cloth to make the previous model/ equations work.

I am a layperson when it comes to physics, but sometimes it's best to ask someone to take a second look to detect obvious BS. This is why I advocate having random idiot (like myself) with a juvenile's sense of humor on every executive board. This would stop things like the Facebook/ Meta debacle from happening.

If Dark Matter has been proven and detected, I would love to know.


When your model works 99999 times out of 100000, it usually isn't the model's problem.  In fact, when you're in that situation, trying to change the model at all to correct that 1/100000 issue breaks half of the things that were correct in the old model, so you're left with a new model that gets that 1 issue correct and 50000 already well established things wrong.

Much better to come up with something that fits into the current model, like a particle that doesn't interact via electroweak/strong forces or very weakly interacts, which doesn't break anything, and then try to figure out why that couldn't be before you go farking everything up.
 
2021-11-12 11:26:37 PM  

baron von doodle: TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.

Or.... Considering it still hasn't been detected, Dark Matter is some made up BS to to fit a square peg into a round hole.

There is a model of the universe they accept and the math doesn't work based on observed motions of celestial bodies. Instead of rethinking the model, Dark Matter was invented out of whole cloth to make the previous model/ equations work.

I am a layperson when it comes to physics, but sometimes it's best to ask someone to take a second look to detect obvious BS. This is why I advocate having random idiot (like myself) with a juvenile's sense of humor on every executive board. This would stop things like the Facebook/ Meta debacle from happening.

If Dark Matter has been proven and detected, I would love to know.



imgs.xkcd.comView Full Size



turns out, if an idea if very obvious, the scientists who think about the issue for a living thought of it nearly immediately, or else a grad student the metaphorical boomers in the field hate for being too clever thought of it only a bit after. In dark matter's case, people tried very very hard to find a palatable explanation (and try even harder with dark energy). This "obvious BS" is one of the best theories that PhDs who dedicated years of study, who actually can do the math involved, have come up with.

Sometimes insight from random people does help! The key is realizing that it's not the rule; it's the exception, and acting like what is essentially the entire astrophysics community is full of morons is both arrogant and idiotic. Dunning-Kruger epitomized. You admit that you're an idiot, which is the first step. The last is acceptance.
 
2021-11-12 11:52:31 PM  

Tranquil Hegemony: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.


I'm going to go out on a limb, here, and say there's a little bit of wiggle room between having less than an accurate grasp of the subject of dark matter and being objectively stupid. But I understand your frustration.
 
2021-11-13 12:00:01 AM  

lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED


Dark matter is whatever is sold on the dark web? /s
 
2021-11-13 12:40:07 AM  
Dark Matter doesn't make black holes because Dark Matter probably doesn't exist.

Our math for the Universe got all squiffy and we've slapped dark matter and dark energy monikers on the "things that makes the math work as we understand it."

That's fine and all, something we don't quite get is off and we gotta start somewhere. But the reality is it could be dark matter just as we try to describe it or it could be several different things we don't even have names for or tools to observe with, up to and including we farked up the math based on bad assumptions about the universe.
 
2021-11-13 3:32:33 AM  

baron von doodle: TWX: Interesting.

As an admitted layman I wondered if dark matter could be Planck-limit black holes, entities so small and with event horizon radii so small that they would no longer interact with strong nuclear, weak nuclear, or electromagnetic force, essentially turning into the absolutely smallest possible points of gravity that were too small to physically interact with any other matter due to their event horizons being too small to encompass any other particle, but I guess likely not.

Or.... Considering it still hasn't been detected, Dark Matter is some made up BS to to fit a square peg into a round hole.

There is a model of the universe they accept and the math doesn't work based on observed motions of celestial bodies. Instead of rethinking the model, Dark Matter was invented out of whole cloth to make the previous model/ equations work.

I am a layperson when it comes to physics, but sometimes it's best to ask someone to take a second look to detect obvious BS. This is why I advocate having random idiot (like myself) with a juvenile's sense of humor on every executive board. This would stop things like the Facebook/ Meta debacle from happening.

If Dark Matter has been proven and detected, I would love to know.


It has been detected gravitationally. Something is there bending light and distorting galactic clusters that are colliding. Something is causing gravitational interactions within and around galaxies that is not baryonic matter and dark matter is what they call this stuff. It is not a constant, it clumps gravitationally and pulls baryonic matter and light along for the ride, but we have no current means other than gravity with which to measure it.

Gravity means something is there.
 
2021-11-13 3:38:37 AM  

akallen404: Tranquil Hegemony: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

This is exactly wrong. We have very specific theories as to the nature of dark matter particles and they're in the process of ruling them out. Just like they did with the Higgs boson.

Anyone who thinks "they call it dark matter because they don't know what it is" is objectively stupid.

No, it's exactly right. There are at least a half dozen highly plausible theories for the Dark Matter Hypothesis and most of them have nothing in common. This article was written by someone who assumes ONE of those theories (evidently, non-baryonic cold particles) must be the correct one. WIMPs would not interact the way the article describes, though, and neither would any of the modified gravity models.


Well, dark matter was the subject of the author's research, it is his area of expertise and so he writes from his expertise. He also talks shiat about string theory. Most scientists are  opinionated in their area of expertise.
 
2021-11-13 4:39:15 AM  

Mustakraken: lifeslammer: And here I thought "dark matter" was used by intelligent scientists to describe the idea that a lot of mass is missing from our universe based on solid math and that


WE HAVE NO IDEA WHAT THE FARK IT ACTUALLY IS OR SHOULD BE CALLED

We've got interesting circumstantial evidence of some of it's nature.

The classic example is the Bullet cluster, 2 massive collections (Superclusters) of galaxies that have collided and passed through one another.

The net mass can be charted in a few ways, and it's location is further past the collision point then the hot interstellar gas that was part of the collision.

This can, so far as we can ascertain, only be explained by the majority of the mass consisting of particles that don't interact with other matter save through gravity.

I have probably butchered this explanation, but the broad strokes are a compelling case for dark matter as a particle of some sort.


What is Dark Matter and Dark Energy?
Youtube QAa2O_8wBUQ
 
2021-11-13 6:31:08 AM  

BolloxReader: Well, dark matter was the subject of the author's research, it is his area of expertise and so he writes from his expertise. He also talks shiat about string theory. Most scientists are  opinionated in their area of expertise.


It's ALOT more common for people to have strong opinions about subjects they know very little about than subjects in which they legitimately are experts. Dark matter research is a great example of this because the data is both very niche and very hard to interpret. At this point in the process, the only reason anyone believes that any ONE theory must be the correct one is because they have a surface level understanding of the theory and haven't done any real work in the field.

There are debates going on between which model or combination of models fits the data BETTER, but those are basically complicated arguments between mathematicians. If the person you're talking to can't describe the actual notation for the model (eg the various MOND flavors or the Lambda CMB mafia) then they're probably just spectators.
 
2021-11-13 6:36:52 AM  

TWX: I thought that it was pretty straightforward, the term itself is something of a placeholder describing a phenomenon that has not yet been itself thoroughly enough explained, based on observations made in the 1960s by Dr. Rubin that the amount of mass in galaxies was insufficient to account for their rotational behavior.


It is much more than that.  There is also the interactions of galaxies with each other in clusters of galaxies. There is the direct measurements of how much gravity there is galaxies by observing how much they gravitationally bend light. Dark matter is also needed to actually form the observed structures of the universe: starting with the big bang the only known way calculations result in a universe that looks like our own is by assuming dark matter.

So there are multiple lines of independent evidence that suggest that dark matter a exists. And is it really that strange that a form of matter exists that either barely interacts or does not interact with the matter we see or itself except by gravity?  May I introduce you to the neutrino that was introduced to keep conservation laws working. It will probably not be stopped if the Earth is blocking its path as it will fly through it as if nothing was there unless it gets very unlucky. It took decades before experimentalists detected it.

Finally, the measured percentage of dark matter in galaxies is not always the same which is a hard thing to explain by modifying gravity.
 
2021-11-13 7:38:16 AM  
akallen404:

It's ALOT more common for people to have strong opinions about subjects they know very little about than subjects in which they legitimately are experts.

stewart lee loch ness monster
Youtube FzOv14fA-BI
 
2021-11-13 7:43:58 AM  

Glockenspiel Hero: Honest question- now I'm confused.  It's been a long time since I studied relativity.

Imagine a particle of dark matter on a hyperbolic orbit around a black hole with an apohole (?) inside the event horizon.  The particle has to conserve energy and according to TFA, doesn't have frictional losses.  So it's carrying the same energy out as it does in which you naively would think would mean it escapes, which it by definition cannot

The only thing I can think is that as the dark matter particle approaches light speed it's converting energy not into velocity but into mass- it ends up inside the hole much heavier but without the velocity to escape

Any actual physicists out there know the answer?


There are a lot of wrong answers to this comment, but we can answer this question without using a black hole at all. As you approach a mass, the velocity required to be in orbit about the mass increases. So, if you were to insert  satellite into Earth orbit at a geosynchronous velocity (for example), but at a lower altitude, that satellite wouldn't be in orbit at all- it'd be well on its way to crashing towards the Earth.

The event horizon marks the point where the escape velocity of the black hole is the speed of light. Anything dipping below that event horizon is acted upon by a gravitational force that outweighs whatever velocity it has.
 
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