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Comment on Can you have an infinitely long wavelength of light? Or is there some maximum?

There is no upper limit, so really this comes down to how big the universe is.

It’s properties would be that it’s extremely low energy … and basically impossible to detected as you’d need a universe-sized antenna.

For short wavelengths you’ll eventually concentrate so much energy in once spot that it will form a black hole. So that would be the lower limit.

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FRYD@sh.itjust.works ⁨1⁩ ⁨day⁩ ago
The idea that a and very small wavelength would cause a black hole doesn’t really make sense to me since I thought a black hole requires mass. I’m no physicist, so I don’t really know.

A search about light with a Planck wavelength came up with this result which seems to claim that eventually the wavelength would become so small as to no longer be capable of holding information and would essentially do nothing.

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- remon@ani.social ⁨1⁩ ⁨day⁩ ago
  
  The idea that a and very small wavelength would cause a black hole doesn’t really make sense to me since I thought a black hole requires mass.
  
  It’s mass OR energy.
  
  Light, even though massless will still bend (and be affected by distorted spacetime) because it has energy in form of momentum. (See: gravitational lensing).
  
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  - calcopiritus@lemmy.world ⁨12⁩ ⁨hours⁩ ago
    It is affected by gravity. But does it have gravitational pull? The thing about black holes is that they have a lot gravitational pull.
    
    I’m asking because I honestly don’t know.
    
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    remon@ani.social ⁨8⁩ ⁨hours⁩ ago
    They do indeed. It’s totally minuscule of course.
    
    Everything that has energy deforms spacetime and spacetime affects how anything with energy moves.
    
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- knightly@pawb.social ⁨19⁩ ⁨hours⁩ ago
  What the two other replies have neglected to mention as the cool side-effect of light affecting the curvature of spacetime despite being massless is that it’s theoretically possible to make a black hole out of nothing but light. The concept is called a “Kugelblitz”, en.wikipedia.org/wiki/Kugelblitz_(astrophysics)
  
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- yetAnotherUser@discuss.tchncs.de ⁨1⁩ ⁨day⁩ ago
  Mass and energy are basically the same thing though. Since E = mc² you can substitute mass in any equation with E / c².
  
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sbeak@sopuli.xyz ⁨1⁩ ⁨day⁩ ago
Interesting, I learned something new today :D

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jaybone@lemmy.zip ⁨1⁩ ⁨day⁩ ago
How would you create the infinite wavelength? Would you redshift a light source for eternity? Would you have to move it at the speed of light?

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- remon@ani.social ⁨1⁩ ⁨day⁩ ago
  Infinities are generally outside of practical applications, so you wouldn’t. It’s more of a thought experiment.
  
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ellypony@lemmy.world ⁨1⁩ ⁨day⁩ ago
this is actually one of the most interesting things I’ve read in awhile.

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Zwuzelmaus@feddit.org ⁨1⁩ ⁨day⁩ ago
I’d say we have set an artificial limit: at some frequency/wavelength, we do not call it “light” anymore. Around 1mm, we call it “Radar” or “microwaves”, and at about 1 m or more, we call it “radio”.

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- remon@ani.social ⁨1⁩ ⁨day⁩ ago
  Unless you specifically say “visible light” I assume “light” to just mean electromagnetic radiation.
  
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  - Successful_Try543@feddit.org ⁨1⁩ ⁨day⁩ ago
    Otherwise, the answer would be trivial, about 800 nm.
    
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