I have several hypotheses of my own. If the big bang actually happened, I suspect it was more to the order of 50-100 billion years ago rather than just 13.8 billion years ago. The longer timeline eliminates the need for the unprovable inflation theory. It also would allow for many generations of stars to form. If 20% of the stars of each generation were too small to go nova and simply burned out to cold cinders then after several generations 80-90% of the stars would be cold, dark and unobservable with only a small percentage still hot enough to be seen. In other words no inflation theory would be needed and dark matter would simply be cold ordinary matter and not some exotic dark particle. While theorists love to tell us about gravitational lensing, they don't seem to acknowledge that in a earlier, smaller denser universe this lensing would be extreme so that today we are getting a very distorted view of anything that happened. Basically we are looking at a contorted kaleidoscope of things which have changed or no longer exist. Even the refractive indexes of the gases in a denser early universe would alter the spectra we see.
My personal favorite is that there are at least three universes existing in the same place at the same time with each affecting the other. We can only see the one we live in now. Which universe we exist in when we die has been called heaven or hell. You choose what you want to believe about the origin of the universe, who we are, why we are here and where we are going.

There are several models excluding dark matter. Here is one http://physicsworld.com/cws/article/news/2012/oct/01/dark-matter-alternative-tackles-elliptical-galaxies

Where did you read theee is any evidence of dark matter. Hundreds if not thousands of experiments done and not one has revealed any evidence dark matter exists. There is howere a great dwal of new evidence building that the so called "dark matter is actually just cosmic plasma, particles and free planets/asteroids floating in open space. This evidence is being found on multiple deep space scanners that are finding matter where non was thought previously.

Dark matter and dark energy are indications that the theories are wrong.

Principle of Preservation of Energy and Momentum and dark mattet detection.

By Giorgios (Gio) Vassiliou
(Founder and Inventor of Transcedental Surealism in visual arts - Architect)

T°=total quantity of energy and momentum before interaction (eg collition)
T¬=Total quantity of energy and momentum after interaction.

So if => T°= T¬=>T°-T¬=0
If the measures of the interaction ends up in result =0.Then the principle of preservation (energy & momentum) is correct.
My opinion is that, this is the more accurate method to dectect the dark matter's undetected(so far) particles, by the amount of missing energy. Because the accuracy of that method will provide the exact amount of dark matter that appeared in a collition or so.
So we end up in a condition, where T°-T¬=Non zero number =>
T°-T¬=A=>A =Dark energy or mass intetacted to the collition or so.
Sincerely
Giorgios (Gio) Vassiliou
Founder and Inventor of Transcedental Surealism in visual arts-Architect

Maybe the old theory of a pervasive aether should be dusted off: https://en.wikipedia.org/wiki/Aether_theories

Hate it when you ask questions, but don't answer them.

Dark energy & dark matter are just bad mathematics... The names were created by the world's scientists to be place-holders for: "We just don't know!"

Mr.Zwicky Was correct in 1933 that more mass was required to account for how fast galaxies move with distances to apart . [expansion]. He called it dark matter. Dark matter may also exist and has existed as specta line as fields of neutrinos, Formed from the universe with it first stars. Photons from stars, give measurement [time] As a constant of direction with negative mass. As Galactic drift on the fringes of all galaxies within the universe.. The question is does dark matter exist ? Jacktar

dunno why this site always tries to push the entirely false narrative that there is evidence of dark matter; postulation simply just isn't evidence itself in any way, shape, or form, at all. any time any experiment looking for supposed dark matter/energy found anything at all, it's always some more stuff that we already knew existed... like that one that found massive amounts of baryonic matter that we thought couldn't (and wouldn't) be there, but there it all was allofasudden!