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I know this is probably dumb on my part but am I the only one that had "dark matter" pop into my mind?
by zw123456 11y ago
I know this is probably dumb on my part but am I the only one that had "dark matter" pop into my mind?
- cgs1019 11y agoNeutrons are electrically neutral but they still interact electromagnetically (they're composed of charged quarks). They have a magnetic moment, for instance [1]. So they wouldn't be dark the way "dark matter" appears (heh) to be. [1] - https://en.wikipedia.org/wiki/Neutron_magnetic_moment https://en.wikipedia.org/wiki/Neutron_magnetic_moment
- drjesusphd 11y agoIf dark matter particles had a magnetic moment, how would we know?
- gliese1337 11y agoThey would interact with photons, allowing us to see some effects of concentrations of dark matter against background light sources.
- Kronopath 11y agoDark matter isn't made of protons, neutrons, or anything as pedestrian as that. It's a sort of "placeholder name" for an effect seen in situations like the collision of galaxies, where there seems to be more gravitational attraction between the two of them than there should be given the matter observed in them. It's as if they had a whole bunch more mass to them, but for some reason that mass is interacting gravitationally, and not in any other way or through any other forces. Scientists can model this by assuming that this type of gravitational-only matter is real, calling it "dark matter", because we don't have a better sense of what it really is. The stuff made in this experiment, on the other hand, has more to do with what you find in something like a neutron star—clumps of neutrons (which are regular, non-dark matter) packed closely together—albeit in an extremely small scale compared to the star.
- deleted 11y ago[deleted]
- akiselev 11y agoThere aren't any known arrangements of neutrons that are stable without protons. Solo neutrons don't exist for longer than 10-20 minutes before decaying into protons and I doubt these tetraneutrons exist for longer than a few seconds unless they're moving at relativistic speeds (and even then, for not much longer). Unless there is something drastically different going on in the interstellar medium, neutrons as dark matter is extremely unlikely.
- noobermin 11y ago>Solo neutrons don't exist for longer than 10-20 minutes Don't equate the bound states with the unbound states.
- ars 11y ago"If a four-neutron nucleus did occur it lasted about a billionth of a trillionth of a second before decaying into other particles."
- noobermin 11y agoSure, but his reasoning of "single neutron is unstable implies a bound state containing neutrons is also unstable" is not necessarily sound.
- akiselev 11y agoWhy is this reasoning unsound? The fact that, after centuries of theoretical and experimental physics, we have yet to see stables neutrons in any configuration other than with protons in an atomic nucleus? We know pretty accurately the decay rates of single neutrons and now we know that all the way up to a tetraneutron that the particles are unstable on the order of minutes and seconds. What evidence is there that we are wrong?
- caf 11y agoThe number of centuries for which we've even known of the neutron's existence is 1, and that's rounding up!
- deciplex 11y agoDark matter is probably popping into and out of all our minds, all the time, and we just don't notice it.