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Solfe
2003-Feb-08, 07:05 AM
I had an odd thought, because this website. Why can't you dodge lasers? Because you can't see them coming. I guess that is sort of true, assuming only one beam was fired. But let's imagine a series of pulses, aimed by a person. That you can dodge, assuming the first shot missed. Technically, you are simple moving randoming and hoping, but that how airplanes avoid gunfire.
But on to the weird part. What would you see? First nothing, a flash from the gun, then a pulse appearing next to you and receeding into the distance? Or a nothing followed by a solid beam orginating at the source and a pulse traving into the distance?
Am I over thinking this?

Solfe

g99
2003-Feb-08, 07:20 AM
Unless a laser has something to reflect and refract off of you wont see anything. So unless the air is really dusty or fogy or misty, ect. You wont see anything.

But since the beam will travel at the speed of light, you probobly will be dead before you even register that it fired.

P.S. Welcome to the board!! This is a great open community. You will love it here!

David Hall
2003-Feb-08, 08:33 AM
I believe that's correct mostly. if the first beam misses, and if there's enough particulate matter in the air to scatter the beam a bit, then you can treat it sort of like a tracer bullet. You can see the path of the pulses as they come, but can you dodge them in time?

If there isn't enough particulate to scatter the beam, such as in a vacuum, then it's basically invisible, both to you and to the firer. The first you'd know about it was when it hit something, hopefully not you.

This is also assuming that the laser is set in the visible range to begin with; if it's a microwave laser, for example, then I doubt it would be visible even when scattered.

darkhunter
2003-Feb-08, 10:38 AM
Assuming suficient particulat matter in the air to scatter enought light to make the laser visible, and a visable laser; you would see a series of straight lines that appear and dissapear as the guy shooting pulles the trigger--there would be no effect of motion other than sweeping across.

A simple test: get a flashlight with a relatively narrow beam. On a foggy night go out side and blink it around--you will see the beam flash on and off, but not move out. Could also use a dark room with a lot of fine dust/powder floating in the air...

traztx
2003-Feb-10, 10:40 PM
If you can get sight of whatever scope is being used to aim the laser then maybe you have a change to avoid being targetted.

Compare with avoiding getting shot by a gun. If you are not where the barrel is pointing, then you don't have to worry so much about the bullet .

sacrelicious
2003-Feb-10, 11:09 PM
the final word on sci-fi laser guns:

they are visible because a relativly benign blast of phosphores is shot out along with the activation of the beam. this is done so that the user of the gun will be better able to correct his aim should he miss the first time. this reasoning is similar to that behind the "tracer" rounds that the army uses for night fighting. and the beam only appears to move because the trail of phosphores does.

now a laser can be dodged the same way a bullet can be dodged: extreme luck, or anticipation of where the assailant was going to fire. now the reason characters in the Star Wars movies are able to dodge lasers is simple because they are all equipped with "light clovers", as will be revealed in Episode II.

and that, my friends, how you justify fictional cliches!

<font size=-1>[ This Message was edited by: sacrelicious on 2003-02-10 18:10 ]</font>

Gramma loreto
2003-Feb-10, 11:35 PM
On 2003-02-08 02:05, Solfe wrote:
But let's imagine a series of pulses, aimed by a person. That you can dodge, assuming the first shot missed. Technically, you are simple moving randoming and hoping, but that how airplanes avoid gunfire.
Actually, the random movements are more than just hoping. When conventional munitions are used against an aircraft, the shooter has to lead the target to account for the distance and direction the target will travel by the time the round gets there. If you move randomly, the shooter has a much more difficult time computing the lead. In this case, it often winds up being the shooter who is doing the hoping by resorting to "spray and pray" fire.

With a laser, leading is of no significant concern since at the ranges involved, the time it takes the beam to reach the target is so short that it's instantaneous for practical purposes.


But on to the weird part. What would you see? First nothing, a flash from the gun, then a pulse appearing next to you and receeding into the distance?
Assuming the laser is operating at a visible wavelength, normal atmospheric scatter probably wouldn't be enough to allow you to see the beam in daylight. Even if you could see it, since the scatter is traveling at c just like the primary beam, you wouldn't have time to dodge it anyway. Most likely though, you wouldn't be able to see the beam unless it were pointed right at you...in which case, it might just be the last thing you would ever see.

Cheers...Loreto

[edited formatting]

<font size=-1>[ This Message was edited by: Gramma loreto on 2003-02-10 18:36 ]</font>