Awesome Silly Science Fiction Weapons 1

I've received a couple of private messages after my last post from people who enjoyed my criticism of science fiction technologies and weapons. Many asked for me to provide further information about awesome but ultimately ridiculous science fiction weapons. I chose a very popular weapon as my first awesome but silly science fiction weapon:

The phaser guns from Star Trek.

Disclaimer: I’m not a physicist, but I take physics classes at university. All corrections by more educated physicists and people who understand this topic are very welcome!

Phaser guns are fantastic devices. They seemingly weight very little, have several settings (including a highly efficient stun setting which seemingly works on almost all species), can be carried easily and if you need them, they’ll shoot a deadly laser ray which will instantly vaporize the targeted enemy (we’re going here with the highest setting, the one which can make people disappear). There’s only one problem with the phaser: it will and can never exist. The thermal radiation alone would instantly kill the user. A handheld weapon which produces the insanely high heat required for the vaporization of a human being would have to be immensely hot. Remember, we’re not talking here about burning someone to a crip, we’re talking here about vaporizing them to the point where they disappear in an instant. Let’s just use a real-life example: human corpses usually take 2–3 hours to be cremated in crematoriums. This requires 1,400 to 2,000 degrees Fahrenheit (approximately 1090 degrees Celsius). Only bone fragments and ash will remain. Phasers however leave little to no traces behind. They instantly disintegrate the enemy. The energy required to break a specific bond in a molecule is known as bond dissociation energy. The energy required to break a specific bond in a molecule is known as bond dissociation energy. This value varies widely depending on the type of bond (e.g., single, double, triple) and the specific atoms involved. For example, breaking a C-H bond typically requires about 410 kJ/mol, while a C-C bond requires about 348 kJ/mol. However, vaporizing a human body does not involve breaking covalent bonds like these. Instead, vaporization requires overcoming intermolecular forces (e.g., hydrogen bonds in water), which is a separate process with much lower energy demands. Let’s use some math here (we’ll go with someone whose body weight is 70 kilograms, the average human male weight on Earth): the usual mass of water in a human is about 0.60×70 kg=42 kg0.60×70kg=42kg. First, we need to heat the water from body temperature (~37°C) to 100°C. Energy=mass×specific heat×ΔT=42 kg×4.18 kJ/kg°C×63°C≈11,100 kJ.Energy=mass×specific heat×ΔT=42kg×4.18kJ/kg°C×63°C≈11,100kJ. Next, vaporize the water: Energy=mass of water×heat of vaporization=42 kg×2260 kJ/kg≈94,920 kJ.Energy=mass of water×heat of vaporization=42kg×2260kJ/kg≈94,920kJ. 11,100 kJ+94,920 kJ≈106,020 kJ (or 106 GJ).11,100kJ+94,920kJ≈106,020kJ(or 106GJ). But it doesn’t stop there: humans are not just water. The remaining 40% of the body (proteins, fats, bones, tissue etc.) would require additional energy to vaporize. For simplicity, assuming similar energy requirements, the total energy could rise to ~150 GJ. To deliver this energy instantly (e.g., in 1 second): Power=150 GJ1 s=150 GW.Power=1s150GJ=150GW. To give you an example of how much energy you would need: the entire U.S. power grid generates about 450 GW at peak demand. To illustrate this further: we now know how much energy we need, but what temperatures would be required? We know that about 176.7 million joules of heat would be required to vaporize a human body weighing 70 kg, starting from body temperature, but Joules (J) is a unit of energy, while degrees Celsius (°C) is a unit of temperature. Let’s just put it this way: you would require several million degrees Celsius to achieve this effect. At such an extreme temperature, the energy of the laser would be sufficient to vaporize any biological tissue almost instantaneously. A temperature of 100 million degrees Celsius is found in the core of stars and is associated with nuclear fusion processes (100 million degrees Celsius instantly vaporized the victims of nuclear bombs during WW2 at ground zero). But my argument wasn’t that phasers couldn’t exist in theory, my argument was that they are ultimately silly weapons. Why are they silly? Well… phasers would kill the user as well. We live in an oxygen rich atmosphere. Oxygen is a form of gas, as we all know! At 100 million°C, the energy emitted by the phaser would ionize all atmospheric molecules (oxygen, nitrogen, etc.), stripping electrons and creating a plasma. This process would release intense X-ray/gamma radiation and trigger a massive shockwave from rapid superheating and expansion of air (even in a vacuum, the beam’s energy alone would vaporize nearby matter). To sum it up: firing such a beam would create a fusion-level plasma event, obliterating the shooter and surroundings. Captain Picard would fire his phaser, but only once. That’s why phasers will never exist. But I should also say that we don't need them. A simple laser gun like the one depicted in the James Bond movie "Moonraker" would perfectly do its job. My childhood James Bond dictionary claims that the Moonraker laser guns use beams which are around 5000 degrees Celsius in temperature. It's more than sufficient to kill the enemy. We don't even have armor which protects you against such a hot beam. Your enemy (as the movie correctly depicts) wouldn't be vaporized, but they would die. There are, unfortunately, no sources which tell us about the energy output itself, but that's fine. To quote the Angry Video Game Nerd: Better to be a mystery than to be wrong.