Sherlock Holmes and Dr. Watson decided to go camping. When they reached a clear spot in the campsite, they pitched their tent under the stars and went to sleep. Sometime in the middle of the night, Holmes woke Watson up: "Watson, look up at the stars, and tell me what you deduce."
Watson said, "I see millions of stars and even if a few of those have planets, it's quite likely there are some planets like Earth, and if there are a few planets like Earth out there, there might also be life."
Holmes replied, "Watson, you idiot, someone stole our tent."
