Here’s a joke I would play if I had a time machine:
Go back in time to visit a random physicist. Congratulate them on their groundbreaking theory on time travel, and then leave.
The Collected Ramblings of a Mad Blogger
Here’s a joke I would play if I had a time machine:
Go back in time to visit a random physicist. Congratulate them on their groundbreaking theory on time travel, and then leave.
Or, go back in time and leave behind history books on early 21st century. (They won’t beleive it anyway, so why bother making something up?)
Or –
Go back in time, prove that you’re a time traveler, and leave behind a Martian-English dictionary.
How about –
Build one time machine inside another, and have them travel in opposite temporal directions just to see what would happen.