That dark matter..
zecri77: All who have any kind of thought into the Matter aka..universe and who the fruk nose???feel free
MJ59: Dark matter is a form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total mass–energy density or about 2.241×10−27 kg/m3.
That stuff hey?
MJ59: La matière noire est une forme de matière censée représenter environ 85% de la matière dans l'univers et environ un quart de sa densité masse-énergie totale, soit environ 2,241 × 10−27 kg / m3.
There ya go!
adamsouthworth: I don't believe dark matter/energy exist. I think this invisible stuff might be a kluge to avoid problems with our present theory of gravity. As far as I know, physicists/cosmologists simply extrapolate from what we observe and our experience of matter/energy to more invisible stuff which explains what we observe.
I know "dark energy" is what physicists invoke to explain a force which propels the universe apart and is thought to constitute roughly 69% of the universe, whereas "dark matter" is what they invoke to explain a force which draws matter together and is thought to constitute roughly 25% of the universe. This means that what we observe is no more than 5% of the universe.
I don't know what explains what we observe, but I consider the concepts dark matter/energy almost Epicurean attempts at a materialist account of things we don't understand to reconcile them with present science. If you believe everything is matter, and you want to explain something you don't understand, you postulate more matter to explain it. This is what Epicurus did nearly 2,500 years ago. His fundamental theory was that everything is atoms and void... And he knew men were afraid of things they don't understand and tended to ascribe them to gods or spirits. Thus, he gave materialist accounts of unexplained phenomena to reconcile them with his materialist model and dispel men's superstitious fear of the unknown - or, to frame it a different way, to undermine men's faith in gods.
Whatever it is that propels the universe apart or draws it together, we believe the value Ω (omega), the average density of the universe, will determine the fate of the universe. And in the case of the cosmological constant (which dark energy attempts to explain), we have a fine-tuned force to 119 powers of ten which led to the emergence of life. The physicist Paul Davies likens the chance this force would take this value to getting 400 heads in 400 coin flips. So these forces are powerful, unobserved, gave rise to life against immense odds and determine the fate of the universe...And we don't know what they are. I believe this puts us in a far worse place than Epicurus nearly 2,500 years ago. We see powerful forces which inspire religious awe or superstitious fear (however you choose to frame it) and want to reduce them to atoms and void. And like Epicurus, many scientists today are engaged in a cultural battle with religion. The absence of a physical explanation of 96% of a reality which created life against all odds and determines the fate of the universe is an unenviable place to start.
(Edited by adamsouthworth)