4 ms·
The lack of density is the cause of confounding behavior. A normal human perspective on 'hot' or 'cold' relates to collections of matter at the pressure and de
by mjevans 6y ago
The lack of density is the cause of confounding behavior.
A normal human perspective on 'hot' or 'cold' relates to collections of matter at the pressure and density that we live within. There is ample material (mass) and opportunity for energy exchange (conductivity), so if something is relatively hot or cold there is a large difference in potential energy and much opportunity to 'correct' that difference by equalizing energy.
The WIMP gas they describe would be __highly energetic__ (hot), but also extremely sparse (vacuum). For any given atomic element present it's rather hot. Yet the actual energy density within a given cubic meter of space, relative to some idealized vacuum, is nearly zero compared to the dense muggy energy in a cubic meter of even frigid polar arctic night air.
- varjag 6y agoI assumed it was some sort of giant intergalactic "clouds"/bands? If this is the case how it remains localized enough given the particle velocities over (assuming) billions of years? There has to be some sort of containing field but it can't be its own gravity. Or is WIMP basically uniformly distributed, high energy component of interstellar medium?
- carterac 6y agoI believe the gravity keeps it from diffusing out too much. The high temperature creates a pressure that keeps it from collapsing into balls. Not an expert though!
- varjag 6y agoWell it was said this is plasma with densities of like 10 particles per m3 so there is hardly any pressure. We know what kind of gravity it takes to keep particles this hot together: this is how we have stars. But it's hard to see how gravity can keep an object this vast, diffuse and energetic together.
- sulam 6y agoNote, you've both used WIMP here, but that's another thing (weakly interacting massive particle -- a candidate theory for dark matter). You want the acronym WHIM, for warm hot interstellar medium.