Quote:A clear sky of typical moisture content will present an equivalent black body temperature of roughly -30C, winter or summer, day (yes, day) or night. And so while not at a few degrees Kelvin (!), the sky does present as a pretty cold heat sink.
Quote: think of my metallic OTA. It contains heat. I think of heat as a substance, a quality, a stuff;
Quote:I have a very hard time getting my mind around that concept your words clearly describe. It doesn't make sense to me that the infinite reservoir of perfectly cold space which is so far away, would have an impact on my little telescope, because my little telescope is a mile or more from that reservoir. I don't see how it (space) impacts it (the scope).
--------------------- --------------------- "Nothing exists but atoms and empty space. Everything else is opinion." Titus Lucretius Carus 99-55 B.C.
Quote:First of all, can things get to absolute zero? I think the answer will be "no", but I want to ask.
Quote:Second, if a thing could get to absolute zero, would it then cease to exist?
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"After the Laws of Physics, everything else is opinion" -Neil deGrasse Tyson
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Quote:"No, but I don't see how we could detect it, since we detect objects by the radiation they emit. It it's at absolute zero, it's emitting no energy. Anything we do to it to make it detectable would have the effect of imparting energy to it, and then it would no longer be at absolute zero. " Well, that certainly makes sense, Dave.OK, you've gotten me to feel I understand how radiative cooling contributes to dew formation. Now, I would like your instruction about the atomic/subatomic end of radiative cooling.Does heat cause the atoms/molecules to vibrate (dance, shimmy and shake, whatever it is they do) or is this vibration what heat is?What is the process/mechanism that cause the vibration to become infrared radiation?Infra-red is just photons of a particular energy in the electro-magnetic spectrum, just to the side of visible light photons. Right?
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Quote:That was an easy to understand and helpful explanation, Jarad.I am curious about the word blackbody. I have heard that word use in association with heat and in association with quantum physics before, but I have never thought to ask; why do we refer to blackbodies when we are talking about heat? I suspect the word black doesn't (so much) refer to color as to a certain energy state, but I am only guessing.Otto