Just the other day I was sitting down and doing the kind of nerd stuff I do as a science fiction writer. I was thinking about having particle beam weapons as one of my possible armaments for my military science fiction series Exodus. I had already incorporated lasers and magnetic rail-guns into the mix, and was using particle beams on my ships. I thought of a description in Star Trek in which phasers were described as particle beam weapons, and thought it would be really cool to use something like that in the story, though they wouldn’t disintegrate objects like in Trek, merely vaporize them, with all the attended superheated steam and ash that would fill the area (something else they tend to ignore in most literature and movies). I looked up particle beams on the net, trying to find a description of what they would do to a living creature, and found nothing. I still figured they would put a lot of heat into whatever they hit, since fast moving particles convert kinetic energy to heat energy. So I just figured I would do the equations and see what happened. I started with a gram of matter flung from the weapon at 1/10 light speed, using the formula ½ M(Kilograms) x velocity (meters) squared. This gives a result in Joules, and about 4.184 joules equal one calorie, the energy needed to raise the temperature of one gram of water by one degree centigrade. I figured it would take about a thousand degrees to vaporize a body, which would be an energy input of about a million calories, or 4.184 million joules. I plugged in the figures and came up with an energy of 450,000,000,000 Joules (yes, that much) which was about as much as 450 lightning bolts, a lot more than I would want to stand close to. So I toned it back to a tenth of a gram and a hundredth light speed. This comes to 900,000,000 Joules, quite a difference but still just a bit too powerful. But things are looking up for a weapon that is actually usable and carries enough matter for many uses. What about a twentieth of a gram and a hundredth light speed? Now we get 4,500,000 joules, just what we need to vaporize a hundred kilogram body, and a weapon that makes mathematical sense. Or does it? We have to look at the recoil of the weapon. Recoil you ask? Yes, recoil, because according to Newton’s laws there is an equal and opposite reaction to any action. And the twentieth of a gram speeding out of the barrel of our weapon at one hundredth light speed (30,000,000 meters per second) will cause a force of 1,500 meters per second on our one kilogram weapon, probably too much to handle with a naked hand. It would accelerate the 100 kilogram body holding it at 15 meters per second, or about 1.5 gravities. Quite a kick, but still doable. In Refuge I use a normal space propulsion called grabbers, or Ether Paddles, that could also be used for recoil compensation, so I will go with this weapon for some applications in the story.
The idea of this exercise is to see if certain weapons are feasible. It also points out a problem that is ignored by many writers and most screen writers, who seem to live in a world in which there is no equal and opposite reaction to the actions they portray. First let’s look at some examples from real life. Watch a film of a World War 2 battleship firing its main guns in a broadside. The Missouri was a good example, 50,000 tons of warship, firing 9 one ton shells. The ship actually moves sideways in the water in reaction to the guns firing, even against the resistance of the liquid. For another example watch a main battle tank like the M1A1 Abram fire its main gun. The entire seventy ton tank rocks backward just a bit. Of course this is ignored in many books and movies. I remember reading a book years ago about a high tech helicopter unit that used magnetic rail guns to fire high velocity rounds that could totally wipe out any armored vehicle made. Sounded like a great weapon, but the author didn’t mention anything about recoil effects, which could and would affect the forward velocity of the helicopter. Hell, the way he described the weapons they might have knocked the chopper on its ass. And remember the Arnold Schwarzenegger movie, Eraser. They had a mag-rail weapon that could blow a van ten feet into the air. And Arnold was walking forward firing two of the weapons, one under each arm. He should have been thrown through the air like he was holding two forward pointing rockets. These are just a couple of many examples where writers don’t know or just simply ignore the laws of physics. Seems to me that they could write a better story by using the laws of physics to their advantage. Maybe that’s just me, but I intend to do as much of it as I can in my own stuff.