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[-] lowleveldata@programming.dev 256 points 3 months ago

It'd be impressive if they fire it at like half the speed of light

[-] Evil_Shrubbery@lemm.ee 78 points 3 months ago

I mean, any other non-c speed really.

[-] Glowstick@lemmy.world 103 points 3 months ago

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.

[-] Bassman1805@lemmy.world 58 points 3 months ago

(For anyone curious, the speed of light in earth air is like 99.97% as fast as in vacuum)

[-] jaybone@lemmy.world 22 points 3 months ago

Bunch of nerds in this thread.

[-] Vilian@lemmy.ca 15 points 3 months ago

You're in science_memes what did you expected?

[-] ASeriesOfPoorChoices@lemmy.world 6 points 3 months ago

exactly where they should be.

[-] LilDumpy@lemmy.world 5 points 3 months ago

Ya, but that's JUST slow enough to be able to see it.

[-] DannyBoy@sh.itjust.works 15 points 3 months ago

Maybe it's going to be space lasers.

[-] 5oap10116@lemmy.world 34 points 3 months ago

Do you know what the religious affiliation of these space lasers will be?

[-] dohpaz42@lemmy.world 21 points 3 months ago

You have a lot of chutzpah to ask such a question. Oy! What would your mother say?

[-] TheFriar@lemm.ee 6 points 3 months ago

“You’re so skinny why are you not eating”

[-] shasta@lemm.ee 12 points 3 months ago
[-] marcos@lemmy.world 7 points 3 months ago

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.

[-] sinkingship@mander.xyz 1 points 3 months ago

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?

[-] Tlaloc_Temporal@lemmy.ca 6 points 3 months ago

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.

[-] Eril@feddit.org 15 points 3 months ago

I would be especially interested in speeds larger than c 🙂

[-] Evil_Shrubbery@lemm.ee 13 points 3 months ago* (last edited 3 months ago)
[-] Xavienth@lemmygrad.ml 10 points 3 months ago

Well that's pretty easy, just fire it anywhere except a vacuum.

[-] PythagreousTitties@lemm.ee 11 points 3 months ago

But I never use my vacuum. Might as well fire a laser at it!

[-] Evil_Shrubbery@lemm.ee 2 points 3 months ago

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.

[-] dev_null@lemmy.ml 1 points 3 months ago

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.

[-] qjkxbmwvz@startrek.website 4 points 3 months ago* (last edited 3 months ago)

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.

[-] SirSmokeAlot@lemmy.ml 2 points 3 months ago

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?

[-] qjkxbmwvz@startrek.website 1 points 3 months ago

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."

[-] SirSmokeAlot@lemmy.ml 2 points 3 months ago

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.

[-] qjkxbmwvz@startrek.website 2 points 3 months ago

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).

[-] AFC1886VCC@reddthat.com 18 points 3 months ago

Imagine if they made it fire so slow that you could just do a dark souls dodge roll to avoid it

[-] Catoblepas@lemmy.blahaj.zone 10 points 3 months ago

Would you accept 10,000 times slower than the speed of light?

[-] MonkderVierte@lemmy.ml 4 points 3 months ago
[-] swordgeek@lemmy.ca 2 points 3 months ago

Pffft. Amateur.

[-] Redderthanmisty@lemmygrad.ml 1 points 3 months ago

Yeah, but this requires that the light be travelling through a dense medium to slow down. It still speeds up again when travelling through air or vacuum

[-] Jumuta@sh.itjust.works 7 points 3 months ago* (last edited 3 months ago)

just shine a laser through a thing of zircon (n=index of refraction=1.923~2)

so speed of the laser in the zircon = c/n ~c/2

[-] rimjob_rainer@discuss.tchncs.de 6 points 3 months ago

Then we could finally have Star Wars laser guns.

this post was submitted on 25 Jul 2024
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