# Lasers as weapons **URL:** \ **Category:** Factual Questions\ **Created:** [March 30, 2004, 2:45am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230 "2004-03-30T02:45:35Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [March 31, 2004, 9:55pm UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/41 "2004-03-31T21:55:11Z")
> [@Bosda Di'Chi of Tricor](#): > > Why? A beautiful response, representative of much of the reasoning and fair-mindedness you’ve displayed here all along. **CalMeacham** , vellly intelllesting. I’d never heard of that. I’d assumed that what BDCoT meant was that the item heated up so quickly that it fractured “on impact” from the uneaven expansion of the material. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [April 1, 2004, 1:02am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/42 "2004-04-01T01:02:22Z")
> [@Cardinal](#): > > **CalMeacham** , vellly intelllesting. I’d never heard of that. I’d assumed that what BDCoT meant was that the item heated up so quickly that it fractured “on impact” from the uneaven expansion of the material. How charming. Now you’re misrepresenting what I said to others. The laser _vaporizes_ the material, converting it to a high-density plasma state. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [April 1, 2004, 2:02am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/43 "2004-04-01T02:02:13Z")
> [@Bosda Di'Chi of Tricor](#): > > How charming. Now you’re misrepresenting what I said to others. > [@Bosda Di'Chi of Tricor](#): > > The damage is not _thermal_, as you suggest, but _concussive_, with minor thermal effect. I didn’t mean that you said the actual words “on impact”. I was putting it in quotes because in my assumption, there wouldn’t be any real impact, and it wouldn’t be so quick. > [@](#): > > The laser vaporizes the material, converting it to a high-density plasma state. So in layman’s terms, it burns through. Yes, I realize that you don’t mean that it oxidizes the material, especially as it may be in an effective vacuum, but without the specifics you only now mentioned, “burn” is not an unreasonable term. In any case, it doesn’t affect the idea of the laser having to be held on the spot for more than, say, a thousandth of a second, depending of course on how much got through the weather conditions between the plane and the missle. Concussive effects are made on impact. You’re just fishing for ways to be offended, I guess. We can play this game where you act like a dork and I sweep it aside with my judo of reasonable niceness, or you can just stop now. You’re not winning any admiration with this program. ---
**Author:** ![Wikkit](https://avatars.discourse-cdn.com/v4/letter/w/c0e974/32.png) [@Wikkit](https://boards.straightdope.com/u/Wikkit)\ **Post date:** [April 1, 2004, 3:23am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/44 "2004-04-01T03:23:08Z")
> [@](#): > > _Master Control_: > For example, the harmless laser pointers (I assume they’re real lasers, right?) work on AA or AAA batteries, but what would you need for something more powerful? laser pointers usually run on 1.5 or 3 volts, that’s one or two AA or AAA batteries. If you were to make a kill laser, you’d want to scale up the power supply, lets say using car batteries, at 12v. 20,000 joules to kill a person, provided by an earlier poster, divided by 12 volts is 1667 Coulombs. A Coulomb is the amount of charge transfered in one second at 1 amp. So if your laser is 100% efficient, and you can keep it trained on a point on a person for a full second (I expect they’d try to move, but that’s just me), then two or three large car batteries (at 500-1000 amps each) should be able to power it. And **Cardinal** , you’re being a jerk. ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [April 1, 2004, 3:27am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/45 "2004-04-01T03:27:17Z")
Jeez. Everybody’s been in such a bitchy mood since the SDMB went to subscriptions. I hope it passes. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [April 1, 2004, 4:30am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/46 "2004-04-01T04:30:52Z")
I’m being a jerK? I in all complete seriousness don’t know what you mean. Let’s review: I made some attempts at factual statements. One of them was wrong. One of needed appending. I was told that I was wrong on every single point (and that’s a quote with underlining). I listed the things I said that were right. It was denied that “concussive” implies the idea of “impact”, which simply isn’t true. I admitted where the other poster was right, and said that one of my points might have been made vaguely, and pointed out where our difference in terms had been. Issue was then taken with things that weren’t even directed at the other poster. I’m done in life with being pushed around, and I’m standing up for myself IRL and here. I haven’t called anyone any names, have admitted where I was wrong, where others were right, and made clear my unclear statements. I just won’t be bullied. ---
**Author:** ![dakravel](https://avatars.discourse-cdn.com/v4/letter/d/85e7bf/32.png) [@dakravel](https://boards.straightdope.com/u/dakravel)\ **Post date:** [April 2, 2004, 6:45am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/47 "2004-04-02T06:45:07Z")
**Cardinal** , **Bosda** was being a jerk, and you’re getting to that point now as well. Let’s all be big boys and just let it slide. Lasers can indeed have momentum, the most efficient engine imagined would be an anti-matter engine wherein you combine matter and anti-matter which will release gazillions of electrovolts of energy in the form of light. That light would propel your spaceship or whatever. As for how long a laser would need to hit, it probably wouldn’t need to hit for very long at all. Although this depends on whether all of you are envisioning constant fire lasers or laser weapons that are semi-automatic. Basically, it’s a question of how much energy the laser would be putting out per second. You would get that fraction of energy depending on how long you stood in it, and even half a second would be a fairly devastating amount of energy I would think. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [April 2, 2004, 9:21pm UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/48 "2004-04-02T21:21:09Z")
I did let it slide in as much as I didn’t put in anything after my last response. I am going to point out again, though, that I was not the one attacking people or not admitting when I was wrong. I’m just not going to put up with unreasonable insults and attacks in the name of politeness. I’m done with it, period. Thanks for the info. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [April 2, 2004, 11:35pm UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/49 "2004-04-02T23:35:29Z")
I can’t believe this garbage. **Cardinal** , you _were_ wrong, you _are_ wrong, and you misrepresented everything I said. I suggest you look up the word “integrity” in the dictionary. **dakravel** --when anybody 'round here _cares_ about _your_ Humble Opinion, yall write me a letter, m’kay? ---
**Author:** ![DougC](https://avatars.discourse-cdn.com/v4/letter/d/7feea3/32.png) [@DougC](https://boards.straightdope.com/u/DougC)\ **Post date:** [April 2, 2004, 11:38pm UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/50 "2004-04-02T23:38:08Z")
- - - Sam’s LaserFAQ tells how to build most types of lasers (or utilize/drive ready-made ones). If you want to make holes in things, a CO2 laser is among the easiest of all to make and has the highest power outputs. There’s variables involved, but they say you usually start to see burning action at 50-75 watts, and people have built ones as big as 200 watts. - If you want any _other_ type of cutting laser than CO2, you are pretty much left with scrounging used industrial or medical lasers, because it’s cheapest–it would cost far more to attempt to build an example of them from scratch, and many types involve processing critical crystals in ways that simply aren’t possible for a home builder. * * * See the section on “Carbon Dioxide Lasers” at [http://www.repairfaq.org/sam/laserfaq.htm#faqtoc](http://www.repairfaq.org/sam/laserfaq.htm#faqtoc) ~ ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [April 3, 2004, 12:00am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/51 "2004-04-03T00:00:27Z")
I simply won’t put up with this. Take it to the pit, at which point I will ignore it. I’m not getting into a war about this. I just want it understood that I am only defending myself against untrue accusations. I have tried with everything I have to be reasonable. I was not wrong about everything. I was wrong about two things. You haven’t had to beat me to get me to admit that. I’m done just leaving things so as to avoid confrontation. I have not misrepresented what you said. I was not quoting you when using quote marks in my statements, as I have already said. I have explained the differences in our terms, and why I thought you meant certain things. You in fact were rignt about pointing out my errors, when they were errors. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [April 3, 2004, 12:21am UTC](https://boards.straightdope.com/t/lasers-as-weapons/237230/52 "2004-04-03T00:21:58Z")
Lasers are not currently useful as direct weapons in combat theaters. They are essential for targeting, and communication. It is in the realm of space mounted weapons platforms that lasers will almost surely pose a very useful weapons category. For orbit to orbit attacks they have great advantages over most other kinds of weapons. There are no recoil considerations to adjust for, which would be the case for rail guns, or cannons. They have a very reliable straight line targeting solution, unlike orbital mechanics for projectiles, or rocket based weapons. With telescopic observation of the target, correcting the aim for subsequent attempts is much faster, and much more reliable than repeated attempts at range for missiles and projectiles. You also get to find out if you hit your intended target a lot faster, a matter of seconds, anywhere in near earth orbit, as opposed to minutes, or hours for physical projectiles. That makes multiple targeting several orders of magnitude simpler, in tactical planning. The size of space platform for a combat capable laser system would be smaller than the shuttle, given only modest improvement over current technology. Fuel cell “cartridges” could be reloaded after an engagement to provide multi mission capability, if the expense of such a system makes it necessary. The effect of coherent energy attacks with high levels of energy (the 10K and above range in joules) has an effect almost identical to an explosive, with respect to the nature of the damage done. The use of even lower levels of energy can be combat useful if sustained for longer periods, or applied in multiple attacks. Space targets are highly vulnerable assets. That state of affairs would have to change, and in the case of space weapons, the cost of orbiting shields favors the inevitable failure of shield over sword. Much more likely than an orbiting platform, itself vulnerable to tracking and attack, are single use launched systems that attack a small number of times, soon after deployment. Computer controlled, and updated by ground observations, such a system might be able to attack four or five targets quickly, from suborbital trajectories. Such a system might be able to use mobile launch platforms, such as aircraft carriers, or even submarines. Of course the US has signed multiple treaties agreeing not to deploy space based weapons. We all know how reliable the US is in honoring its past treaty obligations. Tris [Previous page](https://boards.straightdope.com/t/lasers-as-weapons/237230.md?page=2)