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Energy weapons: reality and fiction

  1. Aug 11, 2010 #1
    Hi all.
    Sorry if I am posting in a wrong section as I am new there and di not figure it out where my post belongs to.
    I would like to ask about energy weapons in fiction and reality. We have movies, video games, novels where lots of weapons (of different designs) are used. As far as I understand, only laser weapons may be used in our days, although without such a devastating effect (like Death Star) or visual effects (like Star wars, where beam could be easily seen). Also, if I am not wrong - plasma weapons are very unlikely to function.
    The question is about reality of some science fiction weapons:
    1. ion cannon - not speaking about its effect (in star wars - blueish weapon, capable of disaablin ship; in master of Orion2 - yellowish weapons, bypassing armor)
    2. photon based beam weapons (some science fiction novels) - is it real or not?
     
  2. jcsd
  3. Aug 11, 2010 #2
    lasers are photon weapons...

    plasma would be pretty easy to deflect in smaller doses, but a ton of ions, with the associated heat from reactions, could be viable... like a plasma torch the size of a stadium.

    but i have very little info on the subject
     
  4. Aug 11, 2010 #3
    What about "proton torpedoes" (from Star wars), explained as "torpedoes with photon warheads"? They managed to use missiles (nuclear?), then - proton torpedoes. SOme writer even invented "proton grenades", little enough and still devastating.

    In this forum I have read ion cannon cannot be real (yes, that pretty strike from c&c - too).
    In such case: is there any other military technology usable in space,except laser weapons and nuclear warheads?
    "Master of Orion2" uses "Graviton beam", yet gravitons are something -if I am not wrong- yet to be found, something theoretical...or aren't they?
     
  5. Aug 11, 2010 #4

    bcrowell

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    You might want to ask this question here: http://groups.google.com/group/rec.arts.sf.science

    It's going to be hard to get any kind of closed-ended answer to this, since there are so many different ways in which such things have been portrayed in SF, and there is a whole spectrum running from hard SF to soft SF.
     
  6. Aug 11, 2010 #5
    Oddly enough, I just saw a preprint which discusses the limitations of lasers intensity due to pair creation from the vacuum from the laser field.

    The preprint is here: http://arxiv.org/abs/1004.5398

    EDIT: to be a little more clear- this paper places a limit on the use of a lasers as cataclysmic weapons.
     
  7. Aug 12, 2010 #6
    Well, the laser may be used as a "cut" weapon: think about "star wars" blasters, used by clone/storm troopers, not that fictional star destroyers' big greenish rays that travels too slow. While I can admit that laser colour may be corrected - the Big Ray would just make a hole, not blow up. Therefore, no "death stars". The only question about laser weapons (well, we are speaking about reality) is - are they capable of effectively cutting something?
    Example: a huge bridge stands and army B is defending it at all costs. Army A wants bridge to be destroyed, but all conventional attacks fails: missiles taken down,planes, helicopters, troops - everything is repelled. Then some bright mind brings up a powerfull laser and simply cuts columns that support the bridge, one by one. Hurray, victory.
    1st question: is that possible? The physical size of the laser does not matter and the energy can be obtained from neariest 10 nuclear power plants.
    2nd question - still about ion and alike cannons. Is it theoretically possible to create a beam that would be deadly when used in space (except laser)?
     
  8. Aug 12, 2010 #7
  9. Aug 12, 2010 #8
    Thanks for the link. Laser Avenger was the most usefull item there (not speaking about Israeli battle robot with 2 machine guns: not GDI walking tanks, but still...).
    ...and what about the laser cutting?
     
  10. Aug 12, 2010 #9
    Laser cutting of materials?
    Well, it's standard technology today, if that's what you mean.
     
  11. Aug 12, 2010 #10
    Well, I mean big distance (kilometres, or even thousands of them) and cutting, say, a part of well armoured battleship. Is it possible that hostile battleship A is approaching US border and they have a megacanon on the shore - and just cut that ship into 2 parts by one shot?
    Energy consumption is not crucial: let us presume out military guys may use all the powerplants within USA.
     
  12. Aug 12, 2010 #11
    The preprint I linked to places limits on the power of a laser. Remember that in a medium like an atmosphere, a laser will have a decrease in power with increasing distance. This fact coupled with the limits on laser power due to pair production from the vacuum makes the use of a laser as a weapon extremely unlikely.
     
  13. Aug 12, 2010 #12
    Norman, has e+e- pair production from lasers ever been demonstrated in a lab?

    But neither this, nor the atmosphere, prevents lasers from being used as weapons.
     
  14. Aug 12, 2010 #13
  15. Aug 12, 2010 #14
    Yes. See "[URL [Broken] Rev. Lett. 79, 1626–1629 (1997)
    [/URL]
    I agree in the general sense. There are plenty of other issues for lasers as weapons (power mainly, I believe). I was merely considering the fanciful, crazy Star Wars death rays, etc. Cutting a bridge in half from a few miles away with a laser is not likely to be feasible.

    EDIT: Missed Gerenuks post. Nice read. Also, I am far from an expert in lasers. I am sure many more people on here (likely Dr Lots-o'watts included) are much more versed in the practical development and theory of lasers. I had a passing interest in grad school, but have not seriously thought about lasers in a few years.
     
    Last edited by a moderator: May 4, 2017
  16. Aug 12, 2010 #15
    And working full time in the laser industry doesn't make me an expert in every aspect. Is has become a very wide field.
     
  17. Aug 16, 2010 #16
    We have micro tractor beams that can trap and move dielectric particles around the size of bacteria. They're called laser tweezers and optical traps. Technically, you can make one with pretty much any kind of laser, even a laser pointer, and an objective. They're not big enough to trap any spaceships, but I bet we have bacteria shaking in their little membranes.
     
  18. Aug 17, 2010 #17

    mgb_phys

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    Laser tend to be line of sight - so if they are used their only viable purpose is close quarter anti-missile defenses.
     
  19. Aug 17, 2010 #18

    sophiecentaur

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    http://en.wikipedia.org/wiki/Boeing_YAL-1" [Broken]
    The USAF have tested an airborne chemical laser which actually works; blasts tanks etc.. It seems to be the nearest thing to Star Wars weaponry to date.
    Electrically powered lasers are very inefficient and the chemical laser gives the required 'population inversion' when you mix the two appropriate chemicals together. You bet far more bang per buck's worth of fuel you carry on board if you don't use electrical energy as an intermediate stage.
     
    Last edited by a moderator: May 4, 2017
  20. Aug 17, 2010 #19

    mgb_phys

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    Blasts tanks is a little optimistic - it might (just about on a good day with a following wind...) burst a liquid fueled ICBM's fuel tanks
    This is from a device that takes an entire 747 with enough nasty chemicals on board that you would do rather more damage to the target by simply landing on it.
     
  21. Aug 17, 2010 #20

    sophiecentaur

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    You spoilsport. It's a start ain't it?
     
  22. Aug 17, 2010 #21

    Danger

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    Charged particle streams will tend to repel themselves out of focus, but a neutral particle weapon can be quite effective.
    The one that I settled on for fictional purposes in my book is a negative/neutral hydrogen cannon. Basically, negative hydrogen atoms are blasted out of a linear accelerator. The beam can be steered and focused by magnetic lenses. As a final stage before leaving the weapon, the ions pass through a cloud of rarified gas which strips off the excess electrons to neutralize the beam.
    A couple of the sources that I consulted mentioned that this and other particle beams are often preceded by a laser pulse to bore a "tunnel" through the atmosphere for the beam to propagate through.
    It's tough to separate fact from fiction, though. Some seemingly reputable sources turn out to be run by crackpots. I seem to recall that my primary source for the neutral hydrogen beam was an article in SciAm back in the 70's, but I can't cite a specific issue.
    One very good reference source (I have it, but can't find it) was written by Ben Bova as part of a series of guides for SF authors. I think that the title is "Space Weapons". Ben is a hard-core scientist, and his data is rock-solid. He even includes formulae for beam attenuation and such-like. If it's still in print, you can get it through Writer's Digest Books.
     
    Last edited: Aug 17, 2010
  23. Aug 19, 2010 #22
    Thanks for advice - will search how to obtain "Space weapons". One more unwise question: what about gravitons. Wikipedia tells:
    "In physics, the graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory."
    So - were the creators of "Master of Orion 2" very wrong when they introduced "Graviton beam"?
     
  24. Aug 19, 2010 #23

    Danger

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    I wouldn't say "wrong" so much as "premature". Since we don't know whether or not gravitons exist, we obviously have no idea of how to manipulate them.
    They are, incidentally, the basis for the tractor beam as well as artificial gravity, inertial dampers and the like on the Trek shows.
     
  25. Aug 28, 2010 #24

    Danger

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    I don't think that this thread is old enough to count as "necroposting". It got away from me before I had a chance to respond to this question. I've watched all of the Star Wars movies at least half a dozen times, and the first 3 (IV-VI) a couple of dozen times. Frankly, I don't recall ever hearing of a "proton torpedo" in any of them.
    Star Trek, on the other hand, had "photon" torpedoes. They are theoretically feasible, provided a compact enough container and power source could be developed. As proposed by Gene Roddenberry in his original concept for the series, the torpedo consisted of a mass of anti-matter (probably anti-protons siphoned from the warp nacelles) and an equal mass of matter separated by electromagnetic bottles. At the desired time, the bottles were shut off, the contents combined, and BOOM!. He coined the name "photon torpedo" because it sounded cool; he justified that decision by stating that photons were the carriers for the electromagnetic containment vessels.
     
  26. Aug 29, 2010 #25
    Well, "Star wars" franchise ("Tie fighter", "X-wing", "X-wings vs Tie-fighter"....) had proton torpedoes and even some photon (some heavy missile), they weren't in the original movie. The simpliesti missile in Star Wars games was "conclusion missile", supposed to be nuclear. Later - "proton torpedoe", some blueish missile, later some rocket and on the end - "heavy space bomb", without any prefixes.
    Once again, some n00bish thoughts about sci-fi weapons:
    1) energy weapons. Yes, it is imopssible to construct "death star" like toys. But what about using laser as an "annoyance weapon"? I mean, ship may fire laser ray at the enemy, making a hole in the enemy's hul (even a small one), no matter where. Enemy crew hurries to fix it or closes the section. Then another shot, another hole, enemy crew hurries to fix the hole...and so untill we perforate almost everything. By the way, "perforating" enemy ship means they may be distracted from our own fighters/missiles/assault transports approaching. Is *that* possible?
    2) "disabling ray". It worked it Star wars (ion cannon), was a weapon of annoyance in "Master of Orion 2" (same "ion cannon", at some point - neutron blaster). Yes, ion cannon is impossible - but is it possible to repeat "Hoth experiment"? I mean - Big Enemy Ship cruises over us, blocking every route of escape and our primitive transports cannont make it to hyperspace from the surface. Then we fire Big Gun at the Big Enemy Ship, causing enemy's electronic systems to overload - and we do escape, bye-bye Empire. True or false?
     
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