If dark matter has gravity, does it have mass? Can we touch it or see its momentum?

Question

Some decade before a scientist explained why neutrino has momentum though it doesn't have mass. But recent fact shows that neutrino DOES HAVE MASS

Answer 1

Yes dark matter has mass.

You can't have gravity without mass.

Answer 2

Dark matter is not a fact. It's a hypothetical substance. We can't see it or see its momentum because it is theoretical. It is hypothesized to explain "possible" discrepancy between observed mass and gravitational forces within the universe. They simply said, there is so much gravity, probably we do not see some of the matter, then its called dark matter! Then they made some calculations and created a model supporting this thesis.

Gravity is a property of a mass. Nothing else.
Note that photons have no rest mass.
This does not mean that they do not have any mass. Photon's rest mass is too little that can be ignored, but they gain a mass when they are in motion, their kinetic energy creates extremely small mass therefore tiny gravity. According to GR, objects have rest mass and also kinetic mass, as objects accelerate their mass increase !!! This is an observed fact, not hypothesis.

Answer 3

Dark matter may not show up as matter in telescopes but should have gravity. In fact, dark matter was postulated to explain the discrepancy between the observed mass of the universe and the gravitational constants.

Momentum is the product of mass and velocity.

Can you touch something because it has mass? Not necessarily. Can you touch a proton or an electron? No. Can you touch sun? No, but it has mass, isn't it?

Answer 4

Hello dear!
Yes, dark matter does have mass! We do measure its momentum, gravity results and so on, especially in space, since around us we have the conseptual mass overtaking the equations!

Answer 5

sure we can't 'touch' dark matter. but its like knowing that a black hole has mass. how do we know? because of the huge effect its gravity has on surrounding objects and light. like dark matter we can't directly observe it but we can infer its presence based upon what we see happening. do you need to touch something to believe it exists? we have theories that can successfully explain what happens around us, but then there is something they can't explain. so we alter the theory a little bit to account for the observation eg dark matter. then we design experiments to test whether the theory will fly. if it does then its enough for most people to believe it.

Answer 6

You can have gravity without mass. You just need stress-energy. Indeed, light itself exhibits gravity.

So what is called "dark matter" could just be some form of energy (massless particles), but the expectation is that it is made of some form of unknown massive particles (massive as in have mass, not necessarily large).

Answer 7

E= MC2
QED.