Could dark matter not exist?

Post by stan_rogers » Mon, Jun 29, 2015, 11:07 PM UTC

mixmastamyk wrote: post #7

Interesting, I always thought of dark matter as just a lot of extra "dust", the dust that clumps to make the stars that make up the universe. The asteroid belt, the extra mass in our kuiper or oort clouds, etc. The dust that blocks parts of our view of the Milky way. This article (and others I'm now skimming) point out that dark matter needs other magical properties however. Why is that the case? Why does simple "dar…

Post by dragonwriter » Mon, Jun 29, 2015, 11:15 PM UTC

smil wrote: post #8

graycat wrote: post #2

Something has orbits around galaxies failing to follow the law of gravity from ordinary matter. The orbits are as if there there is some more mass with gravity, mass that doesn't interact with light. Something is in/near galaxies is bending light as if there were more mass there than there is from just ordinary matter. So, for that extra mass, call it dark matter . Seems simple enough. "Flaw in the theory of gravity?…

Exactly. Dark matter and dark energy is just a symptom of the standard model of physics being incorrect. >Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.[2][3]…

Post by mixmastamyk » Mon, Jun 29, 2015, 11:24 PM UTC

stan_rogers wrote: post #11

mixmastamyk wrote: post #7

Interesting, I always thought of dark matter as just a lot of extra "dust", the dust that clumps to make the stars that make up the universe. The asteroid belt, the extra mass in our kuiper or oort clouds, etc. The dust that blocks parts of our view of the Milky way. This article (and others I'm now skimming) point out that dark matter needs other magical properties however. Why is that the case? Why does simple "dar…

"Dark dust" would, in many circumstances, have at least an infrared signature (or, rather, a signature that originates in the infrared, even if it has shifted considerably downward by the time we see it). This stuff is "dark" in the sense that the only effects we can see at all (so far, at least) are gravitational. In terms of what we think we do know, that implies mass - but mass that doesn't interact with light exc…

Post by teraflop » Mon, Jun 29, 2015, 11:34 PM UTC

mixmastamyk wrote: post #14

aetherson wrote: post #9

Earlier quoted context omitted.

There'd have to be so much of it that we'd see it. There's way more dark matter than normal matter in the universe (stipulating that dark matter theories as we currently understand them are at a coarse level correct). If it were "dark dust," there would be enough of it that we would be able to detect it through means other than gravitational ones.

Thanks. Given that the Oort cloud is very sparse and we can't see it, and we can't (optically) see even the largest planets on other stars, why would we expect to be able to see it?

Post by mtrpcic » Mon, Jun 29, 2015, 11:54 PM UTC

mixmastamyk wrote: post #14

aetherson wrote: post #9

Earlier quoted context omitted.

There'd have to be so much of it that we'd see it. There's way more dark matter than normal matter in the universe (stipulating that dark matter theories as we currently understand them are at a coarse level correct). If it were "dark dust," there would be enough of it that we would be able to detect it through means other than gravitational ones.

Thanks. Given that the Oort cloud is very sparse and we can't see it, and we can't (optically) see even the largest planets on other stars, why would we expect to be able to see it?