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I am confused. I thought photons were just visible light but I guess these little buggers are everywhere. Also very surprised voyager is using 2.3ghz, that's cr

I am confused. I thought photons were just visible light but I guess these little buggers are everywhere. Also very surprised voyager is using 2.3ghz, that's crazy saturated on earth due to wifi. How these engineers make this all work, is magic to me.

mpreda 2y ago
Electromagnetic radiation includes visible light, radio spectrum, X-rays, etc. Photons.
nilamo 2y ago
> Also very surprised voyager is using 2.3ghz, that's crazy saturated on earth due to wifi Wifi didn't exist when Voyager was launched...
- thsksbd 2y ago
  But the band was free for use, wasn't it? (Obviously not crowded)
  - anotherhue 2y ago
    Available for microwaves since 1947, intentional emission came later in the 80s.
  - ianburrell 2y ago
    The ISM band is 2.4-2.5 GHz. Voyager at 2.3Ghz is outside the band.
drmpeg 2y ago
WiFi is at 2.4 GHz. LTE band 30, satellite radio (XM/Sirius) and aeronautical telemetry all exist between the deep space downlink at 2290 to 2300 MHz and WiFi at 2400 MHz.
noneeeed 2y ago
Nope. It's one of those things that can take a bit to get used to, but everything on the electromagnetic spectrum is just light in the general sense. The only difference between radio-waves, x-rays, infra-red and (human) visible light is the frequency/wavelength. If the frequency is high enough then the waves of light can be detected by things as small as cells in the back of your eye, or the pixels in a camera sensor. If it is too low then you need much larger detectors. Other animals have detectors for different frequencies/wavelengths, allowing them to see either infra-red (mosquitos) or ultraviolet (bees, butterflies etc). What we call "visible light" is just the particular range that our eyes can detect (about 400 to 800THz). If we were the size of a planet, and our eye cells were the size of a radio-telescope dish we would be able to "see" in those wavelengths. In fact, when we see images taken by radio telescopes, those have been essentially pitch-shifted up to something we can see, like the reverse of what we do when listening for bat clicks (where the pitch is downshifted to our hearing range). The wikipedia article has a nice little diagram putting the wavelengths into perspective. https://en.wikipedia.org/wiki/Electromagnetic_spectrum https://en.wikipedia.org/wiki/Electromagnetic_spectrum
- pcdoodle 2y ago
  Thanks for the reply. This makes me think of the dual slit experiment. Does the universe treat everything as a wave to save CPU cycles or something? If we think of light as little balls (at our size i think that would make sense). If we were much bigger, we would think of these longer waves as balls too?
  - SJC_Hacker 2y ago
    Wave-particle duality/quantum mechanics have different interpretations, but since "the math works" and there's nothing better, thats what they go with. One way of thinking of it - everything is a wave until you make a measurement. Then you get a "collapse" (localization) of the wavefunction. Which leads to the question of why the wave function collapses - i.e. how does nature know we want to make a measurement. Which leads to all sorts of crazy ideas like the simulation hypothesis. Which is not a scientific theory, because you can't falsify it, but even very educated people like Neil DeGrasse Tyson have remarked on it.
pythonguython 2y ago
Photons and waves both model electromagnetism. Photons are just the quantization of electromagnetic radiation, where E=hv. This is the whole idea of wave-particle duality. We often describe radio frequencies with waves because they act more like waves than particles (Diffraction, spherical propagation, have an easily measureable wavelength)
einsteinx2 2y ago
Photons are just the quanta or particles of electromagnetic radiation, of which visible light is a small portion of the overall spectrum. So you can have photons of microwaves as well, such as in this case. Or photons of X-rays or gamma rays or infrared light or ultraviolet light or whatever. It’s pretty wild actually just how small a section of the EM spectrum our eyes are sensitive to!
BenjiWiebe 2y ago
2.3 GHz is not saturated due to WiFi. Wifi is 2.4GHz and up. Even the harmonics will be above 2.4 GHz (by definition).
philipwhiuk 2y ago
> Also very surprised voyager is using 2.3ghz, that's crazy saturated on earth due to wifi In addition to it being 2.4GHz, this is the reason for having the National Radio Quiet Zone near Green Bank

mpreda 2y ago

Electromagnetic radiation includes visible light, radio spectrum, X-rays, etc. Photons.

nilamo 2y ago

> Also very surprised voyager is using 2.3ghz, that's crazy saturated on earth due to wifi Wifi didn't exist when Voyager was launched...

thsksbd 2y ago
But the band was free for use, wasn't it? (Obviously not crowded)
- anotherhue 2y ago
  Available for microwaves since 1947, intentional emission came later in the 80s.
- ianburrell 2y ago
  The ISM band is 2.4-2.5 GHz. Voyager at 2.3Ghz is outside the band.

drmpeg 2y ago

WiFi is at 2.4 GHz. LTE band 30, satellite radio (XM/Sirius) and aeronautical telemetry all exist between the deep space downlink at 2290 to 2300 MHz and WiFi at 2400 MHz.

noneeeed 2y ago

Nope. It's one of those things that can take a bit to get used to, but everything on the electromagnetic spectrum is just light in the general sense. The only difference between radio-waves, x-rays, infra-red and (human) visible light is the frequency/wavelength. If the frequency is high enough then the waves of light can be detected by things as small as cells in the back of your eye, or the pixels in a camera sensor. If it is too low then you need much larger detectors. Other animals have detectors for different frequencies/wavelengths, allowing them to see either infra-red (mosquitos) or ultraviolet (bees, butterflies etc). What we call "visible light" is just the particular range that our eyes can detect (about 400 to 800THz). If we were the size of a planet, and our eye cells were the size of a radio-telescope dish we would be able to "see" in those wavelengths. In fact, when we see images taken by radio telescopes, those have been essentially pitch-shifted up to something we can see, like the reverse of what we do when listening for bat clicks (where the pitch is downshifted to our hearing range). The wikipedia article has a nice little diagram putting the wavelengths into perspective. https://en.wikipedia.org/wiki/Electromagnetic_spectrum https://en.wikipedia.org/wiki/Electromagnetic_spectrum

pcdoodle 2y ago
Thanks for the reply. This makes me think of the dual slit experiment. Does the universe treat everything as a wave to save CPU cycles or something? If we think of light as little balls (at our size i think that would make sense). If we were much bigger, we would think of these longer waves as balls too?
- SJC_Hacker 2y ago
  Wave-particle duality/quantum mechanics have different interpretations, but since "the math works" and there's nothing better, thats what they go with. One way of thinking of it - everything is a wave until you make a measurement. Then you get a "collapse" (localization) of the wavefunction. Which leads to the question of why the wave function collapses - i.e. how does nature know we want to make a measurement. Which leads to all sorts of crazy ideas like the simulation hypothesis. Which is not a scientific theory, because you can't falsify it, but even very educated people like Neil DeGrasse Tyson have remarked on it.

pythonguython 2y ago

Photons and waves both model electromagnetism. Photons are just the quantization of electromagnetic radiation, where E=hv. This is the whole idea of wave-particle duality. We often describe radio frequencies with waves because they act more like waves than particles (Diffraction, spherical propagation, have an easily measureable wavelength)

einsteinx2 2y ago

Photons are just the quanta or particles of electromagnetic radiation, of which visible light is a small portion of the overall spectrum. So you can have photons of microwaves as well, such as in this case. Or photons of X-rays or gamma rays or infrared light or ultraviolet light or whatever. It’s pretty wild actually just how small a section of the EM spectrum our eyes are sensitive to!

BenjiWiebe 2y ago

2.3 GHz is not saturated due to WiFi. Wifi is 2.4GHz and up. Even the harmonics will be above 2.4 GHz (by definition).

philipwhiuk 2y ago

> Also very surprised voyager is using 2.3ghz, that's crazy saturated on earth due to wifi In addition to it being 2.4GHz, this is the reason for having the National Radio Quiet Zone near Green Bank