
Where is the universe hiding its missing mass? - dnetesn
https://phys.org/news/2019-02-universe-mass.html
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ncmncm
The running joke in all articles of this kind is that there is, in fact, no
gas anywhere in the universe that is "warm", never mind "hot", by their
measure. It is all plasma at such energies -- the particles are ions, which
interact with one another not by elastic collisions, but by long-range
ensemble electromagnetics, involving current flow. Furthermore, they interact
with very long (up to multi-light-year) range magnetic fields, both affected
by and creating them.

This matters because the dynamics of plasma flow are punishingly complicated,
and the mathematics describing it is intractable. It is complicated in large
part because the positive charge carriers are thousands of times more massive
than the common negative charges; the electrons respond nimbly to fields,
while the nuclei go the other way, eventually, absorbing huge energies,
released when charges reunite. The nuclei also collide with any neutral
species, frequently ionizing them, slowed by them, but dragging them along.

So, there are few better ways to get oneself ostracized, among astronomers,
than to so much as mention "plasma". Every single thing in the sky must be
explained entirely with gravitation, which is better-behaved, mathematically,
or shock waves, likewise.

But you only need look once at the Crab Nebula never to be able to un-see the
turbulent flow that would be impossible in a gas at that pressure.

The rule is that a heavy body can have a magnetic field, but it doesn't do
much of anything -- certainly not affect the motion of quadrillions of tons of
nearby plasma, never mind be affected by them.

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graycat
I'm trying to understand your post:

> But you only need look once at the Crab Nebula never to be able to un-see
> the turbulent flow that would be impossible in a gas at that pressure.

Just what "pressure"? Of what? Where? And near the Crab Nebula (the pictures
are amazing) but how is that relevant, related, does correspond to the _big
flows_ or whatever of the OP?

> The rule is that a heavy body can have a magnetic field, but it doesn't do
> much of anything -- certainly not affect the motion of quadrillions of tons
> of nearby plasma, never mind be affected by them.

In the context of the OP and/or the Crab Nebula, what is the "heavy body"? For
the Crab, that is the neutron star or black hole at the center of the nebula?
For the _filaments_ of the OP, what is the "heavy body"?

Related, the OP is talking about some really hot gas, difficult to see because
it is nearly transparent to visible light. So, why doesn't that gas cool just
by escaping photons? And, how did the gas get so hot to begin with? We're
supposed to accept that the heat came from some quasars?

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ncmncm
My apologies, sarcasm can be confusing.

But recall, there is no gas. Plasma doesn't work like gas. In particular, you
don't need heat to accelerate ions to relativistic speeds, and plasma doesn't
need to be hot to radiate x-rays. It just needs to be, y'know. Accelerated.

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martinpw
Title is unfortunate because missing mass is often equated with dark matter.
However, as the article itself makes clear, this research is nothing to do
with dark matter, instead it is referring to 'normal' baryonic matter that is
known to be present but had so far not been identified.

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edoo
Is quantized inertia still a movement? Last I saw it accounted for the
galactic spin without dark matter, which I thought was an ugly plug for an
obviously incomplete model.

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__john
My impression is that quantized inertia is somewhat of a fringe theory.
Someone correct me if I'm wrong.

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dnautics
it is, but my impression is that, because the proponent has associated it as a
possible explanation for a lot of crazy things like voyager speed anomaly,
which we now know is probably due to outgassing, or EMDrive, which is probably
measurement error.

On its surface it doesn't seem unreasonable.

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supermw
Interesting: In some Christian SciFi stories the missing mass has been
attributed to the mass of heaven and hell.

~~~
ncmncm
This is the extremely popular "God did it" hypothesis, most frequently
employed nowadays to solve white-collar crimes.

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no_gravity
When we play a computer game - say a racing game - where is the mass hidden,
which pulls the cars downwards?

