why dark matter?

Question

when we know that a lot of energy (as electromagnetic waves and particules) is travelling through space, is that not enough to fill in the mass deficit of the universe ?
we know of the duality wave particule or energy equal mass, why do we need dark matter ?

Answer 1

to prove sir isaac newton right of course

Answer 2

The reason they think they need dark matter has been answered by others here. One of the things is that the motions of stars in galaxies do not conform to the distributions of ordinary visible matter that we can observe. Most are happy with Einstein's gravity so they postulate the existence of other stuff to account for the motions of the stars rather than rethink gravity. Some think that perhaps gravity should be adjusted, that what we observe here on earth does not apply over the distances involved on galactic scales. Some think there is a lot of regular matter that does not shine so we just don't see it. Remains to be seen what the outcome will be.

Dark matter may very well exist but then again it may not. Plus it has something to do with the name: Dark Matter.... ooooh, mysterious .... Dark Energy .... like wow, weird. It is part of the game whereby scientists get money and awards and things. And in their little playground the best theory is one that sounds and seems so right that people get lots of money and nobel prizes and stuff first for creating it and then for tearing it down later on.

I remain sceptical until someone actually observes and can demonstrate the existence of this stuff. What I don't understand about it is why does everything we observe seem to be organized as the visible matter is. We don't see strange distributions of stars that are part of a mixed dark matter and visible matter galaxy. And why if there is so much of it isn't there some around our solar system to cause anomalies in our predictions of planetary movements? I could go on with other such questions but I will leave it up to the readers to think about these things. Just because some scientist or group of scientists says something does not mean that it is true or even possibly true.

Answer 3

Because the amount of mass and energy in space that we have estimated still falls well short of explaining why we observe different numbers.

Answer 4

The energy density of radiation in the universe is minuscule and rapidly decreasing. It is not the dark matter.

Answer 5

Well explained
in the link .if there were no dark matter the galaxies would disperse more quickly

Answer 6

there is no dark mater just scientists wishful thinkin because they cant find the missing mass so they invent one.