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Is it possible that dark matter is a cloud of slow neutrons? They wouldn't be able to firm electron clouds and without those they would be invisible.
by frongpik 6y ago
Is it possible that dark matter is a cloud of slow neutrons? They wouldn't be able to firm electron clouds and without those they would be invisible.
- andreareina 6y agoFree neutrons decay on the order of 10 minutes
- frongpik 6y agoAre there neutron-like particles that are stable?
- brokensegue 6y agoWIMPs?
- frongpik 6y agoWimps seem to be exotic particles of unknown structure. My guess is that regular neutrons are enough, so long as they are "fixed" to be stable.
- the__alchemist 6y agoAlong this line, another shower thought: Could it be delocalized (ie very widely spread out) electron wave functions?
- dodobirdlord 6y agoElectrons are charged and thus interact with electromagnetic fields (light), so they don’t fit the requirement for “dark” matter. Huge amounts of unaccounted for matter being in the form of electrons would also skew the charge balance of the universe locally and globally into the negative, which conflicts with observations that the universe has a neutral net charge.
- the__alchemist 6y agoThank you for the explanation.
- codethief 6y agoIn addition to what andreareina said: Neutrons also interact with light while dark matter is called "dark" for a reason.
- frongpik 6y agoInteract enough to drop a noticeable shadow? Iirc, a neutron is 50e3 times smaller than a hydrogen atom.
- nwallin 6y agoNeutrons bonk into stuff. If you're at a rave in a 100ft by 100ft warehouse, you look around and see four other people, but you keep bonking into ... something ... that you can't see every inch you move, you would surmise something is up. If dark matter were a cloud of slow neutrons, we would know quite a bit about it. Actually we wouldn't because we'd all be dead, but that's a different story.
- frongpik 6y agoHow would they bonk onto anything? A neutron is a tiny particle 50000 smaller than a hydrogen atom. Without an electric charge, it would float straight thru anything and we wouldn't know.
- magicalhippo 6y agoNeutrons have a nucleus, just like a proton, and that would bonk into things. Yes the chance[1] of doing so is much less due to it having an effectively smaller radius, but on the other hand there would have to be a _lot_ of them to explain dark matter. There's also a lot of stuff for them to bump into. The interstellar medium is filled with diffuse gas, and there's there's highly energetic events like jets from black holes which when slamming into the neutrons surely would lead to some observable effect. [1]: https://en.wikipedia.org/wiki/Neutron_cross_section#Typical_cross_sections https://en.wikipedia.org/wiki/Neutron_cross_section#Typical_...
- frongpik 6y agoIirc, we'd only need 10 neutrons per each hydrogen atom to explain the dark matter gravity. OK, if neutrons would be observable, are there any weird visual effects in galaxy cores that could be attributed to such neutron clouds?
- magicalhippo 6y agoYou say "only" but that's a _lot_ of neutrons, and space is vast. For one, I'd be very surprised if they didn't bump into each other, cooled down and clumped up like normal matter, which is precisely the opposite of what we expect from dark matter based on observations. Secondly we know[1] from nuclear experiments[2] what happens when neutrons interact with matter. I'm certain a nuclear scientist could list a bunch of effects we'd see if a whole lot of neutrons were hanging around black holes and similar. The whole point of dark matter is that observations show it interact extremely little, if any at all, with regular matter. [1]: https://en.wikipedia.org/wiki/Neutron_scattering https://en.wikipedia.org/wiki/Neutron_scattering [2]: https://en.wikipedia.org/wiki/Neutron_diffraction https://en.wikipedia.org/wiki/Neutron_diffraction