Dark Matter?

Dark matter is a spectrum.

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>>8863800
particle dark matter is meme tier garbage...

MOND has a few hurdles but would be most interesting (i think)...

Dark matter is most likely 10 - 100 solar mass primordial black holes... (both confirmed gravitational wave sources are from binary black hole mergers that are in this mass range) The more gravitational waves measured, that are due to binary black hole mergers (with 1- -100 solar mass range), the stronger this evidence will be...

in short, meme tier shit aside, dark matter is most likely black holes...

>>8864488
>MOND
Hahaha nigga you serious?

>>8864436
How hasn't this meme already died?

>>8864488
Thats what I was thinking as well but black holes distort the light around them too much.

>>8864488
>Dark matter is most likely 10 - 100 solar mass primordial black holes... (both confirmed gravitational wave sources are from binary black hole mergers that are in this mass range) The more gravitational waves measured, that are due to binary black hole mergers (with 1- -100 solar mass range), the stronger this evidence w

First off binary black hole mergers and GW sources are the same thing, no other black hole mergers have been observed. So you're basin this on 2 events which aren't well understood.

Secondly there is microlensing which puts extremely strong constraints on black holes in this mass range (pic related). Despite attempts no one has made a mass spectrum which could fit the constraint, be all of dark matter and explain the LIGO events.

>MOND has a few hurdles
You mean a few massive failures that it's architects have given up on entirely. Even the high MONDian himself admits MOND needs dark matter in clusters and there are still other issues.

There's nothing wrong with particle dark matter.

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>>8864690
Forgot image.

Dark Matter hasn't actually been found to exist though, something we can experiment on, right?

>>8864514
What is not dead can never die. Death is a spectrum.

>>8863800
First things first. We believe the universe is expanding and also in the big bang. There are 3 things that indicate this. The abundance of light elements indicates the universe was in some high temperature state in the past, big bang nucleosynthesis. Hubble diagram indicates that we can measure how fast galaxies are moving away from us by measuring redshift of light and also that galaxies farther away are moving faster. Lastly is the cosmic microwave background, blackbody radiation left over from the early universe that hasn't interacted for a very long time and is just reaching us and is also nearly uniform.

From this we define the scale factor of the universe a(t). Physical distance d = ax. Consider two particles at rest with a distance of x between them and a=1 at this time so their physical distance is just x. The expansion of the universe dictates their physical distance at a previous time is less than x, and at a previous time greater than x. The energy density of non relativistic matter scales as a^-3 since their energy is constant and their number density scales as a^-3. Radiation on the other hand scales as a^-4 since we also add in the fact that their wavelengths will be longer and energy is inversely proportional to wavelength.

When the universe was very hot early on certain light elements began to form like H, He, Deutorium(H+neutron), Li. The theory and measurements for these match well and allow us to measure the baryon density=proton + neutron density. But we have a problem here. The baryon density only accounts for at most 5% of the critical density, the amount needed for the universe to be flat(which it nearly is). But matter density(measured by considering growth through time with a(t) scaling) gives estimates of 20-30%. The rest has to be filled with matter-like substance which scales the same with matter, a^-3, but is non-baryonic. Note that all ordinary matter we have seen is baryonic. We call this new stuff dark matter.

It can be seen as a galactic framework, giving structure to galaxies.

>>8864488
>MOND
>says particle dark matter is meme tier
wow. is this what its like to see distilled stupidity? MOND even says particle dark matter needs to be a thing

>>8864762
just because we havnt been able to detect it yet doesnt mean it doesnt exist. Its akin to people figuring out there must be electrons simply based on observations of macro events in electromagnetic forces. same shit but gravitational geodesics(because gravity isnt actually a force)

>>8865932
Thank you for taking the time to help my understandin but I'm still struggling with the presence of a matter that, by using our current level of technology, is unobservable. It could be equally as outlandish to claim that god's hands are holding galactic entities together.

There are two options for interpreting dark matter.

1) Perhaps there is some magical invisible particle.

2) Perhaps the actual shape of galaxies is more complicated than they look in the 2D projections we can see with telescopes.

Option two is superior in almost every way but still everyone fanboys for number one. Option one is stupid and doesn't make any sense. Look at this chameleon field that has been floating about the literature lately. It is fucking stupid and ridiculous.