We can only visually detect objects above absolute 0 degrees kelvin. so, has anybody thought of an alternative theory that proposes matter existing at zero or even negative energy level? invisible matter? matter not giving off any radiation, where not only electro magnetism acts weirdly but not "gravity" ( spacetime warp) or it's effects?
Can a negative temperature exists ? Yes. (negative energy level i dont know what this mean). It is not speculative science, only some scientific curiosity. https://en.wikipedia.org/wiki/Negative_temperature Why not, but how could this matter be so cold in space ?
good question, with even non baryonic gravity waves delivering energy. I think there is a cold dark matter theory.
Perhaps the cold matter could be some Bose-Einstein condensate. https://en.wikipedia.org/wiki/Bose–Einstein_condensate Trying to find something about this hypothesis, it seem that it could be a possibility. Per example here : https://link.springer.com/article/10.1140/epjc/s10052-020-8272-4
the constraints for zero temperature DM are narrow. It can not absorb or reflect any radiation. Would the Bose- Einstein plama fit that limitation?
It would be nice if i could answer this. But i suppose i am not skilled enough and i do not have many observational facts to draw a conclusion on this eventuality. I can only propose an alternative solution to the dark matter problem (but it has nothing to do with matter).
does a black hole "give off"(active production outward) energy that is detectable ? while i realize there may not be a simple answer to that question my purpose is to define the nature of detectable version perception of existence by relative actions of other matter/objects etc e.g if there was an anti-gravity particle how could we detect it ?
"other matter objects" might define a sensor, camera that directly captures the original emitted radiation. or an acho glow of it;s reflection. The OP question was, could dark matter (and I believe it might be a red herring) give off no light, because it is too cold to do so. and it is not radioactive either. have we even detected gravitons, tons of it? or tons of the higgs boson? Hawking's radiation, relativity jets
are all things photonic by observable conclusion ? e.g if we are not using photonic devices, what are we using ?[point= can it be detected using something other than its heat] does a photon exist outside a vibrational frequency range ? particle ? do any particles not vibrate ? is a particle a stationary object ?(static versus non static?)
Curently i see at least 3 types of "particles" detectors : Light telescop/radiotelescop, for electromagnetic radiation (so photons). Collision detector to detect particles (neutrino detectors, Geiger counter, cloud chambers, etc). Gravity detector to detect gravity waves. Now, to get an image, we can use the first of three here very efficiently, and sometime we can use a little the cloud chambers to say where the particle come from (we see the trail the particles left in the "cloud"). In physic, a "particle" is a generic term that include atom (particle is a "small part of matter"). Smaler particle are named "subatomic particles". So neutron/proton/electron are particles and the atom composed of these three particles are particles. The quarks are particles and they compose the particles neutron and proton. E=h*nu E : Enregy nu : Frequency (vibrational rate) h : Planck constant So if a particle has no energy, perhaps we can say that it dont vibrate. But this is perhaps a too simplified point of view (i am not a specialist), in quantum physic i think that nothing can be in a "resting state". There could be a virtual vibration that can appear in some circumstances (when the particle is accelerated per example). Immobility doesent exists. An other question is : If we vibrate at the same rate as the incoming wave, can we detect it ? A particle is also a wave. Perhaps a better question could be : Do any particle expand like a wave ?
all very pertinent questions, and in a state of matter that is devoid of any energy, not just in place vibration, but even spin. would its presence not be undetectable by any means, safe the effects of its mass on spacetime?
To your last statement , true DE . Dark Energy , the energy of speed . Superfluids . Non Friction motion . Absolute Zero ( and greater to my thinking ) is very interesting . And the magnetic field is extremely confined , extremely small . Because there is no heat . Heat allows expansion . Cold does not .
Think about this: DM in it's halos has to be sustained in place against gravity. We do it by orbital speed, centrifugal "force" so: May be DM is so cold it freezes spacetime to kind of a "solid" for itself.
With this hypothesis, Dark Matter could be the space itself organized in a new unknown state . Some are doing such speculation concerning the inner space of the black holes, saying space could be in a different phase we already know. The problem is, for black hole we can understand why space could be in an other phase, but for space between galaxys, why ? https://www.nature.com/articles/d41586-018-05095-z
If you understand well, the above hypothesis is highly speculativ. In this case i doubt we can draw a law so simple as "gravity is proportional to temperature". On the other hand, gravity could have something to do with "temperature", but not the same as we talk about with agitation of matter. Gravity could be a thermodynamical emergent effet. https://en.wikipedia.org/wiki/Entropic_gravity
In this idea that nebel through out there, , all DM is invisible because of giving off no signal, because at zero kelvin or below, it is not energetic enough to so . so: the inverse square law appears to be unaffected by temperature. it just is. Dark matter becoming visible by getting warmed up and shining would not change the reading on your gravity instrument
Highlighted Disagree DE then DM . Then Galaxies and Quasars Because of superconductivity ( cold ) no friction , hence speed , not heat .
That is an interesting scenario. if I understand right, Energy, existing before the big Bang Bang could be called "Dark" energy, because it must have been there, but we can not see it. or beyond 13.8 light years into the past. The first few years are also opaque to us, but is that because all matter was " Dark Matter" ?--- not what mainstream science found. -- Then some of the dark matter became baronic, turned into galaxies and stars? by emerging internal friction? instead of being supercharged with DE, think of DM as deprived of all energy to the point of invisibility. and additionally not being able to absorb or reflect any energy, waves or particles at all.