Thread: DM Question (as if there aren't enough)

From home.CERN

Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light, making it extremely hard to spot. In fact, researchers have been able to infer the existence of dark matter only from the gravitational effect it seems to have on visible matter.

In some strange way could a light particle remain a wave when observed? Could dark matter have a property that prevents wave function collapse, by not interacting with EMF?

Originally Posted by zinjanthropos

From home.CERN

Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light, making it extremely hard to spot. In fact, researchers have been able to infer the existence of dark matter only from the gravitational effect it seems to have on visible matter.

In some strange way could a light particle remain a wave when observed? Could dark matter have a property that prevents wave function collapse, by not interacting with EMF?

Well if it doesn't interact with EM radiation it certainly won't cause effects that correspond to light behaving like a particle - it won't cause any effects at all!

But what do you mean by "when observed"? Anyone observing, or anything interacting, with the light is, er, interacting with it. So they, or it, are not made of dark matter, clearly.

DM may be vast concentrations of ancient black holes from the beginning of the universe, according to a recent study.

https://www.livescience.com/dark-mat...20new%20study.

Originally Posted by exchemist

Originally Posted by zinjanthropos

From home.CERN

Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light, making it extremely hard to spot. In fact, researchers have been able to infer the existence of dark matter only from the gravitational effect it seems to have on visible matter.

In some strange way could a light particle remain a wave when observed? Could dark matter have a property that prevents wave function collapse, by not interacting with EMF?

Well if it doesn't interact with EM radiation it certainly won't cause effects that correspond to light behaving like a particle - it won't cause any effects at all!

But what do you mean by "when observed"? Anyone observing, or anything interacting, with the light is, er, interacting with it. So they, or it, are not made of dark matter, clearly.

So something that can interact with light cannot observe that which doesn’t? I guess that’s what they’re saying.

Edit: from universitytoday.com

. Neutrinos are a form of dark matter, because they have mass, and weakly interact with light. But neutrinos have such a small mass and high energy that they move through the universe at nearly the speed of light. For this reason, they are known as hot dark matter.Feb 9, 2021

Sounds like they can measure neutrinos, and there’s interaction, so does this contradict home.CERN’s take from OP? Have also read where physicists having trouble measuring neutrino mass so are they(neutrinos) DM or not?

Originally Posted by zinjanthropos

Originally Posted by exchemist

Originally Posted by zinjanthropos

From home.CERN

Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light, making it extremely hard to spot. In fact, researchers have been able to infer the existence of dark matter only from the gravitational effect it seems to have on visible matter.

In some strange way could a light particle remain a wave when observed? Could dark matter have a property that prevents wave function collapse, by not interacting with EMF?

Well if it doesn't interact with EM radiation it certainly won't cause effects that correspond to light behaving like a particle - it won't cause any effects at all!

But what do you mean by "when observed"? Anyone observing, or anything interacting, with the light is, er, interacting with it. So they, or it, are not made of dark matter, clearly.

So something that can interact with light cannot observe that which doesn’t? I guess that’s what they’re saying.

Edit: from universitytoday.com

. Neutrinos are a form of dark matter, because they have mass, and weakly interact with light. But neutrinos have such a small mass and high energy that they move through the universe at nearly the speed of light. For this reason, they are known as hot dark matter.Feb 9, 2021

Sounds like they can measure neutrinos, and there’s interaction, so does this contradict home.CERN’s take from OP? Have also read where physicists having trouble measuring neutrino mass so are they(neutrinos) DM or not?

Well, as Blackadder would say, how dark is dark, I mean, just how dark do you want to be? I'm not sure most people would class neutrinos as dark matter. For one thing, given their tiny mass and enormous speed, it seems unlikely that they will hang around in galaxies, giving them much greater masses than can be accounted for by the visible stars they contain. Because that is the observation that dark matter is invoked to explain. So this sounds to me, without seeing the context, like someone trying to be clever.

But you seem to be making a bit of meal of this "observation" business. To observe EM radiation, you need a detector that interacts with it. Obviously. But nobody claims we can't observe dark matter. If we couldn't observe it we would not talking about it, because we would not know it was was there! On the contrary we do observe it,via its gravitational effect.What we can't do is observe it by its emission or absorption of EM radiation, since it doesn't do either, apparently. That is all.