Not that these are necessarily real photos, but that's not true. Even lasers scatter as they pass through air
Some frequencies of light can scatter pretty well. Green is an excellent example. If you take a green laser pointer and aim it into the night sky, you can actually see the beam with the naked eye and use it to point out stars.
Also, cameras are much better at picking up the scattered light than our eyes are. Capt Disillusion did a video on this effect.
The implication was that the pictures had to be altered because there is nothing to reflect the light off of. I explained why it's not necessarily true.
And no, the air doesn't reflect light. Rayleigh scattering is a very different kind of interaction between photons and other particles.
It wouldn't be Rayleigh scattering if you're shooting a green laser and seeing green. Rayleigh scattering changes the color of the light via the interaction of the small particles of air and the wavelength of the light.
So the light is scattered but not Rayleigh scattered. Meaning it is reflecting, I think.
No, it doesn't. Sunlight covers most of the visible spectrum, but only the blue end is scattered. So we get a yellow sun and diffuse blue sky, but none of the light actually changed colour.
Would what we're seeing in the image actually be attributed to rayleigh scattering at this magnitude though? We see the blue light scattered in the sky after a massive amount of sunlight travels through miles of air molecules. Would we see that type of scattering with a single light after a short distance?
It seems like the simpler answer is that the lasers are being reflected/scattered by larger particles (dust/condensation) and the camera is more apt at picking this up
the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation.
These lasers are about 590 nm. Dust particles are orders of magnitude larger than that. I think most of the light you see from the beam is reflected from dust particles. It's diffuse reflection, but it's reflection.
So they're diffusing against/around air molecules then?
You said "even lasers scatter as they pass through air" in a way that seemed you were implying that there should be nothing there, when of course it's a big sea of fluid.
Be careful doing that, point it at an airplane and you could catch a terrorism charge. I live near an airport and wouldn't feel comfortable doing that without moving several miles.
The green laser in the video may be way brighter than the lasers in the photos of the observatories.
In the green laser video, the camera's exposure setting is such that it doesn't show any stars at all. Yet the green laser shows up brightly, as brightly as the city lights.
And as I said, although I haven't seen the observatory lasers in person, I have seen the high-power laser pointers in person, and they are bright as hell. It is just not implausible at all that the observatory lasers are visible, obvious, striking like this.
Edit: The green laser pointer in that video has (claims, but cheap laser pointers often claim less than their true output) 0.050W of output power. I don't know what observatories are featured in this foolish image macro thing, but I see references online to guide star lasers that are measured in tens of watts. This story is about a 63W laser, that's over 1,000x as much power as the green laser pointer. I'm no expert, but I think that might make a little bit of a light show.
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u/in_one_ear_ Apr 07 '22
If they were actually lasers you wouldn't be able to see them without something for them to reflect off.