Future weapon

[Atgxtg]

19 hours ago, g33k said:

In all human/sniper scale engagements, it's close enough.

Yes, assuming that human scale remains what it is now. But if optics and range improve, it might not be. With a powerful enough laser, that is accurate, and and the right optics shots at tens of kilometres or more could become a real thing. For instance an assassin who wanted to take out some high level official could do it from an aircraft miles away, assuming he could get a clear shot. It would probably make outdoor speeches by politicians a thing of the past, or else the politians would become a thing of the past. The only real limitation is line of sight.

19 hours ago, g33k said:

We don't need to apply correction to the laser, any more than we need Einsteinian physics (rather than Newtonian) for the bullet; even though Newtonian physics is explicitly false (in all circumstances), it's close enough to be usable.  I will note that (although I have not done the math) it's likely that the gravity sufficient to warp the path of light over the course of a shot -- by even as much as a millimeter -- is sufficient to turn the sniper into a thin film of goo... 

Let's see: D=1/2at^2

D= 1mm or 0.001m

a= 9.81 m/s^2

t= (2D/a)^.5

t=(.002/9.81)^.5 = 0.1427 seconds

A light beam would travel about 4280 kilometres in that time.  Probably far enough out not to be a factor for a sniper, unless he is in space with insane optics, but then, at that point you don't really need a sniper to find the target manually.  

19 hours ago, g33k said:

HOWEVER, gravity is irrelevant in ALL cases (even intense/Einsteinian gravity):  if you see it, you can shoot it; the laser will follow the same course TO the target, that the image you're aiming at follows FROM the target; light is light, and follows the same path in both directions.

Not in all, cases, only in anything reasonable for a sniper. 

19 hours ago, g33k said:

Delay on a laser?  About 1/100 of a second, if the target is about 2000 miles away. 

About that. 

19 hours ago, g33k said:

With enough power (and collimation) there is absolutely no reason or limit that would stop a sniper from killing satellites in orbit. 

Yes there is, the speed of the satellite. Unless the satellite is in a geosynchronous orbit, it will probably be travelling too fast (4 miles or more per second) for a sniper to be able to acquire the target. At that point the weapon would need to have some sort of computer guidance system that could track the satellite and even give it some lead time. A satellite 150 miles up would travel about 4.7 miles per second, or about 13 feet in the time it takes the laser beam to reach it from Earth. 

19 hours ago, g33k said:

"Low Earth Orbit" is about 1200 miles.  Geosynchronous is about 22000 miles (these will obviously vary on planets with other than 1G of gravity, but it gives us a reasonable 1st estimate).

Yes, and at that ranges, not only does gravity become a factor again, but the high speeds required to maintain orbit would make the shot impossible for a sniper, and require some sort of targeting computer. 

19 hours ago, g33k said:

This probably calls for XRay laser or other supra-optical wavelength -- the physics of diffraction & collimation is a function of wavelength of the light.  I'd need to crunch some numbers, but it's likely the laser would be (at least) the size of the entire satellite, by the time it hit from the surface of a 1G world.  No nice neat hole, alas!  But with MOAR P0WAR, the planet-facing surface could at least be slagged...

Yeah, but I think it is outside the scope of a sniper. It more like a SAM but without the missile, so SAL (Surface-to-Air_Laser) or more actually a SSL (Surface-to-Space-Laser). 

[Lloyd Dupont]

As a side and tangential note (I am not even trying to disprove infinitely powerful and miniaturised laser gun here) perfectly straight laser ray do not exist. And by the time the ray has travelled barely 1 second (i.e. 300,000km) it is much larger (and weaker) (like some kilometres wide) hence these are safer to use in space. I.e. they weakened to nothing in barely a million kilometres! Handy! 😮   
Whereas your average slugger in space can leave dangerous shrapnels all over a system so as to make further space travel if not impractical, at least hasardous.. 😮 

Edited June 16, 2020 by Lloyd Dupont