4 ms·
It is surprising to me that it is in the visible range.
by cout 1y ago
It is surprising to me that it is in the visible range.
- _trampeltier 1y agoEvery body does emit radiation. Most is in IR range, but since nature is very broad, a very small amount is in a wide band from the spectrum. https://en.m.wikipedia.org/wiki/Black-body_radiation https://en.m.wikipedia.org/wiki/Black-body_radiation You can see it in the picture, the radiation is very wide.
- jvanderbot 1y agoYou'll probably want to compare/contrast that with Fig 1 in the paper https://www.biorxiv.org/content/10.1101/2024.11.08.622743v1.full.pdf https://www.biorxiv.org/content/10.1101/2024.11.08.622743v1....
- lovich 1y agoIf you can see something with your biological eyes, it is emitting energy in the electromagnetic spectrum
- codingdave 1y agoMore likely to be reflecting, not emitting.
- 1718627440 1y agoWhich is actually the same.
- sebastiennight 1y agoSimple experiment: Turn off the lightbulb, close the curtains and check again how many of your household items are still "emitting" light.
- 1718627440 1y agoWhen I provide the necessary energy with the necessary frequency they will.
- IAmBroom 1y agoNo. Not by physics. Not by chemistry. Not by human eyes under varying environmental light levels.
- 1718627440 1y agoI thought reflection works by the photon giving the atom energy, which it then releases in form of another photon, which has the same frequency due to the energy level, but not necessarily the same polarity.
- cout 1y agoI don't know about you, but I have trouble seeing other life forms in a room that is pitch black.
- lovich 1y agoI don’t know what my comment had to do about being in a situation where you don’t see it
- adrian_b 1y agoThe visible range corresponds to the typical energy differences between different states of an outer electron in a molecule, which also correspond to the typical energy differences between the input and output molecules of a chemical reaction. (The near infrared range corresponds to the typical energy differences between different vibrational states of the atoms in a molecule. Such energy differences are smaller than the energy differences encountered in most chemical reactions, which involve extracting or adding atoms from/to the molecule, which obviously needs more energy than the vibration of those atoms, when they remain bound in the molecule.) Thus it is normal and expected that the output molecules of an exothermic chemical reaction may be in an excited state from which they can decay to their ground state by emitting light exactly in the visible range. As long as it is living, in any organism a lot of exothermic chemical reactions happen. In many cases the energy produced by those reactions is used for something useful for the organism (i.e. the excited output molecules transfer their surplus energy to other molecules), but it also may escape as emitted light, reducing the efficiency in the use of the energy produced by an exothermic chemical reaction to less than 100% (the efficiency is also reduced when the energy of the excited molecule is transferred to other molecules than those intended, which eventually results in warming the environment instead of doing useful work).
- jvanderbot 1y agoHooold up. So you're saying that there is something special about the visible spectrum? I've always wondered why most eyes we know of work in that range (modulo some leftovers from our time as aquatic creatures)
- benterix 1y agoYeah, I always unconsciously assumed it's just a random slice, never thought deeper about this. Thanks, HN!
- Y_Y 1y agoI invite you to consider that most of the light that earth species have had available during their evolution comes from a blackbody emitter at about 6000 kelvins (solar photosphere). https://www.sciencedirect.com/topics/physics-and-astronomy/solar-spectra https://www.sciencedirect.com/topics/physics-and-astronomy/s...