2014-04-24
Explanation
The Joke
A woman excitedly tells a man, "I built a time machine! And it's ready to go back into the past!" But there is a catch: it can only go back 30 minutes. She tries to explain that this is still scientifically incredible, but the man is unimpressed. He argues that there is nothing worth going back 30 minutes for.
The woman gets increasingly frustrated, explaining that they could use it to prove it works -- go back 30 minutes and find their past selves. But the man keeps dismissing this as pointless. Eventually the woman says time started 30 minutes ago, and the man says "Let's go then."
They travel back and encounter their past selves talking, confirming the machine works. In the final panel, a woman (possibly a future version or someone else) confronts them, angry that they used the time machine for something trivial. She says: "Actually, your problem was that you organized in threes, so it's 30 minutes, not 30 years."
The Humor
The comic plays on the disconnect between the enormous scientific achievement of building a time machine and the anticlimactic limitation of it only going back 30 minutes. A 30-minute time machine is a world-changing physics breakthrough, but practically speaking, there is almost nothing useful you can do with only a half-hour time jump. The humor comes from the frustrated inventor trying to convey the significance while her companion can only see the practical uselessness.
The final panel adds an additional twist suggesting that the limitation might have been a fixable engineering error all along.