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> Because the light absorption level is so high, the super-black material will also keep temperatures down Can someone with more physics knowledge explain how
by njharman 15y ago
> Because the light absorption level is so high, the super-black material will also keep temperatures down
Can someone with more physics knowledge explain how absorbing more energy will result in reduced temperatures. I would assume the opposite.
- nobody3141592 15y agoIf you are facing something really cold and black - like space then the blacker your radiator is the more power you can emit at a given temperature. In theory a perfectly reflective silver object would never cool down and a perfectly black one would cool to -270C however much power you dumped into it
- ars 15y agoThat is not true. A perfectly reflective silver object still emits blackbody radiation. And a perfectly blank one will absorb light, heat up and also emit blackbody radiation.
- nobody3141592 15y agoA Mr Kirchof would disagree with you if he wasn't dead. A perfect emitter facing an infinite cold sink is in perfect equibirium at the temperature of the cold sink.
- ars 15y agoOf course - but that's not what you said. You said: "...would cool to -270C however much power you dumped into it" and that is not true. And in any case you don't need to be a perfect emitter to be in equilibrium with the temperature of the cold sink, all you need is infinite time, but any emitter, no matter how bad will eventually equilibrize.