Actually, c is the speed of light in a vacuum, but light travels slower through a medium, like air. So lasers shot through air will actually travel slower than c.
I don’t think that’s a great way of thinking about it. I think you’re describing something more like scattering — or maybe absorption and stimulated or spontaneous emission — which does indeed happen, but is distinct from the index of a medium.
If it were indeed “bouncing,” optics wouldn’t really work, as any n > 1 medium would cause the light to go every which way.
If you fire a laser that goes first through vacuum, then through a lens, then again in vacuum, at what speed is the light travelling on the other side?
I didn’t write it out, but what I was trying to get at was that if it would “slow down”, then it would be slower on the other side. The explanation that the light travels longer through a medium with the same speed would therefore make sense to me.
But then again, how it wouldn’t shoot out in every direction, that doesn’t make sense to me.
I don’t know much about light, that’s why i’m asking. And i’m sure some article or paper would have anwers for that question, I might search it on my own.
I think the right way to think about this is as a wave, and in that respect, it’s no different from sound waves. If sound goes through the air, then through another medium, then out the other side back to air, the speed will follow the same general rules as with light. One notable differece is that speed of sound through many materials is faster than through air.
Note also that you’ll get acoustic reflections at interfaces, which is analogous to optical (Fresnel) reflections at interfaces (e.g., reflection off of glass or water).
I mean, any other non-c speed really.
Actually, c is the speed of light in a vacuum, but light travels slower through a medium, like air. So lasers shot through air will actually travel slower than c.
(For anyone curious, the speed of light in earth air is like 99.97% as fast as in vacuum)
Bunch of nerds in this thread.
You’re in science_memes what did you expected?
hot science girls
exactly where they should be.
Ya, but that’s JUST slow enough to be able to see it.
Maybe it’s going to be space lasers.
Do you know what the religious affiliation of these space lasers will be?
You have a lot of chutzpah to ask such a question. Oy! What would your mother say?
A laser strong enough to be used as a weapon will probably not leave a lot of medium on its path.
But the front-most part will still travel at less than c. It will just speed-up after a while.
I’m curious. What happens to the medium? Does it simply get pushed aside? Or pushed along? Or will it eat up some energy and react to something else?
Much like lightning, a powerful enough laser will ionize the air. That ionized air is hot and rises, just like the ionized gasses from combustion.
A powerful laser will look like a beam of fire.
I would be especially interested in speeds larger than c 🙂
Well that’s pretty easy, just fire it anywhere except a vacuum.
But I never use my vacuum. Might as well fire a laser at it!
Yes, ofc - but we’re talking about a weapon here, the air is implied as a medium, and the very-near-c with it.
But a weapon that would construct some sort of structure or a tunnel between it’s position and the target would be something else indeed.
It’s still travelling at c, it’s just bouncing around the medium’s particles on the way. It arrives later because it’s not going in a straight line.
I don’t think that’s a great way of thinking about it. I think you’re describing something more like scattering — or maybe absorption and stimulated or spontaneous emission — which does indeed happen, but is distinct from the index of a medium.
If it were indeed “bouncing,” optics wouldn’t really work, as any n > 1 medium would cause the light to go every which way.
If you fire a laser that goes first through vacuum, then through a lens, then again in vacuum, at what speed is the light travelling on the other side?
It’s same as it was at first. The speed of light depends on the index of refraction of the medium it’s in, but doesn’t depend on its “history.”
I didn’t write it out, but what I was trying to get at was that if it would “slow down”, then it would be slower on the other side. The explanation that the light travels longer through a medium with the same speed would therefore make sense to me.
But then again, how it wouldn’t shoot out in every direction, that doesn’t make sense to me.
I don’t know much about light, that’s why i’m asking. And i’m sure some article or paper would have anwers for that question, I might search it on my own.
Ah, I think I see what you mean.
I think the right way to think about this is as a wave, and in that respect, it’s no different from sound waves. If sound goes through the air, then through another medium, then out the other side back to air, the speed will follow the same general rules as with light. One notable differece is that speed of sound through many materials is faster than through air.
Note also that you’ll get acoustic reflections at interfaces, which is analogous to optical (Fresnel) reflections at interfaces (e.g., reflection off of glass or water).