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Message no. 1
From: shadowrn@*********.com (darren gilliver)
Subject: Laser weapons(and hello again)
Date: Mon Aug 12 15:35:03 2002
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*Grins like a chesire cat*

Well im back on the list again,anyone miss me?

Nah didn't think so.



Anyway on with the question.

Do laser weapons make a sound when they fire? and is the beam they fire wide enough or
bright enough to be seen with the naked eye?

that is all

Darren.(yeah Darren,you know that big red guy)




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<P>*Grins like a chesire cat*</P>
<P>Well im back on the list again,anyone miss me?</P>
<P>Nah didn't think so.</P>
<P>&nbsp;</P>
<P>Anyway on with the question.</P>
<P>Do laser weapons make a sound when they fire? and is the beam they fire wide
enough or bright enough to be seen with the naked eye?</P>
<P>that is all</P>
<P>Darren.(yeah Darren,you know that big red
guy)</P><p><p><br><hr size=1><a
href="http://uk.yahoo.com/mail/tagline_xtra/?http://uk.docs.yahoo.com/mail_storage.html"><b><font
face="Arial" size="2">Get a bigger mailbox -- choose a size that
fits your needs.</font></b></a><br><br><a
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face="Arial"
size="2">http://uk.docs.yahoo.com/mail_storage.html</font></a>;
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Message no. 2
From: shadowrn@*********.com (Bryan Pow)
Subject: Laser weapons(and hello again)
Date: Mon Aug 12 18:15:01 2002
>Do laser weapons make a sound when they fire?

I've never seen a large one fire, so I'd have to ask one of the physics guys
here at my Uni (apparently they had a laser large enough to down a comercial
air liner, but it ate juice like nothing else) but I'd imagine the machine
itself would be soundless. The dustparticles in its path super heating and
exploding (as well as the target) might make a noise tho.

>and is the beam they fire wide enough or bright enough to be seen with the
>naked eye?

Even normal lasers are only seen by the naked eye when there is dust or
smoke in the way that scatteres the beam slightly. I'd imagine that an
Infrared laser would be likely as I believe that is what the Military is
developing for its laser weapon that can blow up fuel tanks in cars etc.
(Side note: Its sometimes useful to take laser sights that are in the
Infrared Spectrum so that only people with thermo can see them)






--

"No grand idea was ever born in a conference, but alot of foolish ideas have
died there."

F. Scott Fitzgerald


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Message no. 3
From: shadowrn@*********.com (Gurth)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 05:50:28 2002
According to darren gilliver, on Mon, 12 Aug 2002 the word on the street was...

> Well im back on the list again,anyone miss me?
>
> Nah didn't think so.

Not miss you as such, but I did try to reach you on your old address and found
it wasn't working anymore :)

> Do laser weapons make a sound when they fire? and is the beam they fire
> wide enough or bright enough to be seen with the naked eye?

Lasers make no sound, and you only see the beam if you're either looking
straight into it, or you see it reflected off something -- like the target, or
from dust/smoke/vapor in the air. (Shooting a laser at a target in a smoke
cloud gives everyone watching a line straight back to you...) That is, if the
laser operates in the visible spectrum; only dwarfs, trolls and people with
thermographic cyberware would see an IR laser, for example.

> Darren.(yeah Darren,you know that big red guy)

I guess that must mean you were in disguise last time we met...

--
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Message no. 4
From: shadowrn@*********.com (Lone Eagle)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 06:20:01 2002
>From: darren gilliver <chrome_ghoul@*****.com>
>Anyway on with the question.
>
>Do laser weapons make a sound when they fire? and is the beam they fire
>wide enough or bright enough to be seen with the naked eye?

Laser weapons will be based around pulse lasers, they will make a noise when
fired as the "beam" will cause thermal blooming, (it will superheat the air
between the weapon and target) this means that some energy will be wasted in
a sharp crack as the hot air expands faster than the speed of sound, however
it will not be the same sort of sound as a rifle or pistol, more like an
electrical discharge, the snapping sound as an arc forms sort of thing.
The "beam" will be bright enough and wide enough that it could be seen
except for two things, firstly the only way you can see a laser is if it
points at you, a normal light radiates in all directions and tends to
relfect and refract in the same way, this means that if a beam of "white"
light is shone past you, you are likely to be able to see the source and if
there is a degree of "pollution" (water droplets, smoke...etc) in the air
you are quite likely to be able to see the beam, shine a torch over the top
of a kettle or a cigarette in a darkened room and you should see what I
mean, you don't actually see the beam, you see the smoke/steam in the beam.
lasers reflect/refract in a much more predictable fasion and radiate through
a much tighter angle, to all intents and purposes parallel in fact, this
means that the levels of pollutants have to be higher... in the movies they
put smoke onto the set when the protagonists have laser sights because it
shows the beam (which let's face it looks cool) that's the first problem.
The second problem, and much more difficult to counter is the fact that
you're dealing with a pulse rather than a beam, the pulse is very short
lived. Remember that you're looking at the speed of light here, the fastest
thing in the universe (that we know of and can conceive of measuring), the
speed of light in a vacuum is approximately 299,792,000 m/s; an Ares Heavy
Laser Plus (is it?) has a range equal to a sniper rifle IIRC, that's 1000 m,
light travels that distance in a vacuum in 1/299,792 seconds that's 0.000003
seconds. in an atmosphere like earth's the speed is reduced although not by
much (and due to rounding will still do the 1000m in 0.000003 seconds).
This means that the "beam" isn't in existance long enough for our eyes to
register it, some of the most sophisticated cameras in the world are used to
monitor laser experiments and I don't think any of them have ever recorded
the pulse.
So while the "beam" would be bright enough to see you won't see it.

Now that was a long winded way of saying no.

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Message no. 5
From: shadowrn@*********.com (Damion Milliken)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 06:35:01 2002
Lone Eagle writes:

> ... (and due to rounding will still do the 1000m in 0.000003 seconds).
> This means that the "beam" isn't in existance long enough for our eyes to
> register it, some of the most sophisticated cameras in the world are used
> to monitor laser experiments and I don't think any of them have ever
> recorded the pulse. So while the "beam" would be bright enough to see you
> won't see it.
>
> Now that was a long winded way of saying no.

Thanks for the good explanation, Lone Eagle. But I have to add one thing.
You're assuming a single photon pulse, emitted in (effectively) an instant,
and travelling to the target in 0.000003 seconds. A real pulse from such a
laser is more likely to be of a measureable length, perhaps only 1/50th of a
second, but much logner than your quoted 0.000003 sceonds. Also, it's very
likely that such a weapon would have a rapidly pulsing beam, say 20 pulses a
second or something. 20 rapid pulses of 1/50th of a second over the course
of a second would more than likely appear pretty much as a continuous beam
to the unaided human eye. If the circumstances were right (like you
described regarding airborne pollutants, laser wavelength, and such), then
this sort of beam would probably be visible.

--
Damion Milliken University of Wollongong
Unofficial Shadowrun Guru E-mail: dam01@***.edu.au
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Message no. 6
From: shadowrn@*********.com (Damion Milliken)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 06:35:04 2002
darren gilliver writes:

> Well im back on the list again,anyone miss me?

Well, yeah. The list has been kind of quiet, actually. I hope that you can
assist in remedying this situation for us ;-). Welcome back!

--
Damion Milliken University of Wollongong
Unofficial Shadowrun Guru E-mail: dam01@***.edu.au
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Message no. 7
From: shadowrn@*********.com (Lone Eagle)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 07:35:01 2002
>From: Damion Milliken <dam01@***.edu.au>
> > ... (and due to rounding will still do the 1000m in 0.000003 seconds).
> > This means that the "beam" isn't in existance long enough for our eyes

>to
> > register it, some of the most sophisticated cameras in the world are
>used
> > to monitor laser experiments and I don't think any of them have ever
> > recorded the pulse. So while the "beam" would be bright enough to see

>you
> > won't see it.
> >
> > Now that was a long winded way of saying no.
>
>Thanks for the good explanation, Lone Eagle. But I have to add one thing.
>You're assuming a single photon pulse, emitted in (effectively) an instant,
>and travelling to the target in 0.000003 seconds. A real pulse from such a
>laser is more likely to be of a measureable length, perhaps only 1/50th of
>a
>second, but much logner than your quoted 0.000003 sceonds. Also, it's very
>likely that such a weapon would have a rapidly pulsing beam, say 20 pulses
>a
>second or something. 20 rapid pulses of 1/50th of a second over the course
>of a second would more than likely appear pretty much as a continuous beam
>to the unaided human eye. If the circumstances were right (like you
>described regarding airborne pollutants, laser wavelength, and such), then
>this sort of beam would probably be visible.

The pulse from most high energy lasers AFAIK is somewhere in the region of
10 nanoseconds in length, IIRC the MP Laser Plus isn't FA (which is how a
staggered pulse like you describe would act IMO) 20 rapid staggered pulses
could be dragged/ tracked over a fairly broad area.
IMOSHO the only place where you see the "beam" of a laser weapon is on the
trid.
It might be worth seeing if Glasnost has put anything on the web about the
Russian Laser weapons, providing they aren't just an urban myth...

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Message no. 8
From: shadowrn@*********.com (Anders Swenson)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 11:35:01 2002
On Tue, 13 Aug 2002 10:22:01 +0000
"Lone Eagle" <loneeagle2061@*******.com> wrote:
> >From: darren gilliver <chrome_ghoul@*****.com>
> >Anyway on with the question.
[snip]

> > This means that the "beam" isn't in existance long enough for our
> eyes to register it, some of the most sophisticated cameras in the
> world are used to monitor laser experiments and I don't think any of
> them have ever recorded the pulse.
> So while the "beam" would be bright enough to see you won't see it.
>
> Now that was a long winded way of saying no.

That dosen't make sense, time depends on low long the pulse is on, not
on the time to target.
--Anders
Message no. 9
From: shadowrn@*********.com (Paul J. Adam)
Subject: Laser weapons(and hello again)
Date: Tue Aug 13 17:05:04 2002
In article <20020812193921.26344.qmail@********.mail.yahoo.com>, darren
gilliver <chrome_ghoul@*****.com> writes
>Do laser weapons make a sound when they fire?

I'd think so. Not from the laser itself, but from the homopolar
generator or supercapacitor you'd be using for power. Even the
experimental coilgun we built made a loud "snap" when fired, as the
coils jumped around in their encapsulation under the huge magnetic
field.

You'd probably also get a 'crack' of expanding ionised, heated air from
the beam path.

>and is the beam they fire
>wide enough or bright enough to be seen with the naked eye?

I'd expect that a weapons-grade laser might (depending on wavelength,
atmospherics etc.) create some interesting visual effects. I've seen a
CO2 laser pulse leave a very short-lived trail of 'bubbles' of ionised
air behind, for instance. The more dust or water vapour in the air, the
more your laser loses and the more heat it dumps and the more likely you
are to get visual and thermal effects.

--
Paul J. Adam

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