# Could dark energy be heat? Could dark matter be stuff that is not seen because of its refraction limits?

Heat has to go somewhere. Would the light and heat of the stars in the universe amount up to being dark matter ...and dark energy ... Dark matter would just be small pieces of stuff. Dark energy would just be heat that has gone into space.

If dark energy was just heat then a warp-drive could be as simple as a sphere with one very hot side.

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Heat can't just live in the vacuum. Because heat is a form of energy and energy is equivalent to mass, heat has to have a material carrier. The most "neutral" type of heat that you probably meant is the electromagnetic radiation. Dark matter can't be made out of electromagnetic radiation because it would escape, in 100,000 years, away from the galaxy. Instead, dark matter must be made of something that survives in a halo around the galaxy and permanently modifies its gravitational field. In fact, we know that most of the dark matter must be cold dark matter which moves very slowly – much slower than the speed of light. So light is the maximally wrong candidate for dark matter.

Dark energy is the "opposite" of electromagnetic radiation, too. Dark energy, by definition, has a negative pressure close to $p=-\rho$, minus energy density. On the other hand, radiation has $p = +\rho/3$, a very different equation of state.

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They expected a fall in the velocity that matched newton's laws of gravity (which still work extremely well in systems like this). Except instead of the velocity of bodies dropping off as $1/r^{2}$ after a point, they found it to be roughly constant.