Laser guns have long been a staple of science-fiction. Why then don’t we have any yet? Jeff Hecht answered the question:

• Lasers aren’t energy efficient. They work by converting other forms of energy into light, but a lot of energy is lost as heat in the process.
• The only way for a laser to kill is through heat. But the human body is mostly made up of water, and it requires a lot of energy to heat water up. Thus a laser gun would require a prohibitive amount of power.
• The one thing lasers can do well is burn out a person’s retinas. However staring at the sun has the same effect, and anyway the Geneva conventions don’t allow for such tactics.

To read more about how lasers can be used to take out non-human targets, as well as equally heinous alternatives for aspiring evil overlords, click here.

Source: Light Speed