Fire photon torpedoes!

While reading this article about the development in 1962 of the first sci-fi video game, Spacewar, I stumbled across the answer to a question I've harbored since I was a little tike watching Star Trek: What exactly is a "photon torpedo"? As it turns out, the term didn't originate with the writers of Star Trek at all...

The game pits two spaceships against each other, both orbiting a central star. The developers borrowed the orbit mechanic from Marvin Minsky's Minskytron, a non-interactive demo that showed off geometric interactions, and the star background was lifted from Samson’s "Expensive Planetarium" software. But the interaction model was all new. Just getting the orbit to respond to player actions in real time was a challenge, given the limited processor power, but Russell credited MIT colleague Dan Edwards with finding a way. At the time, there still wasn't enough computing power to apply gravity to the ships' projectile weapons, Russell said, "so we decided they were photon torpedoes, unaffected by gravity."

Now you know. The explanation even makes sense. Sort of.