Two astronauts land on Mars. Their mission: to check whether there is Oxygen on the planet “Give me the box of matches” says one. “Either it burns and there is Oxygen, or nothing happens.”
He takes the box, and is ready to strike a match when out of the blue, a Martian appears waving all his arms yelling “No, no, don’t!” and grabbing the match away.
The two guys look at each other, worried. Could there be an unknown explosive gas on Mars? But he takes another match…and now, a crowd of hysterical Martians is coming, all waving their arms yelling “No, no, don’t do that!”
The astronaut says to his buddy, “It looks serious. What are they afraid of? He turns to the Martian and says “We mean you no harm, but we’re here for Science, to know if man can breathe on Mars”.
Before the Martian can react, he strikes the match, which flames up, burns down, and…nothing happens. “Why did you try to prevent us from striking a match?”
The leader of the Martians says, “Today is Yom Kippur!”