At first (and second glance), I thought your comment was from floo, Sririam! Could hardly believe it was you.
The rest of the universe appears to be made of a mysterious, invisible substance called dark matter (25 percent) and a force that repels gravity known as dark energy (70 percent). Scientists have not yet observed dark matter directly.
I see SKofS has explained it better. It is still largely unknown.
Brownie,
No...no.
Dark Matter and Dark Energy are
not evidence for anything. They are the presumed
solutions for certain observations.
Scientists found that galaxies are receding away from one another at accelerating rates. This was not possible unless something was pushing them apart... like some sort of an antigravity force. They gave this force the name of Dark energy.
Similarly, scientists calculated, based on gravitational forces in galaxy clusters, that the total mass of the universe was required to be considerably more than was observed in the known universe. Also certain structure formations etc. needed to be explained. Therefore they proposed something they called Dark Matter which is 5 times more abundant than normal matter but which cannot be sensed or detected by our instruments.
So....the 'evidence' are the above observed phenomena. DM and DE are the proposed solutions or answers for these observations. They are not evidence for anything !
In fact, there is absolutely no proof at all for either Dark Matter or Dark energy. They are
conjectures that seek to explain the above observations. They could get disproved or eliminated anytime due to alternative explanations.
As I have said earlier...I have no problems with such conjectures. They are necessary and even inevitable given the nature of the cosmos.
But when similar conjectures or hypothesis are proposed for phenomena such as NDE's or 'miracle' cures or ESP or for the nature of the mind.....they are dismissed because we cannot prove the existence of such things as after-life, biofield, common consciousness and so on. So our conjectures are invalid! LOL!!!
This is where my earlier statement that 'reason and logic' are subject to background, culture, beliefs and mindset..... and are not uniformly applied, becomes relevant.
Cheers.
Sriram