Which astronaut wears the biggest helmet?The one with the biggest head.

What does an astronaut do when he gets angry?He blasts off:

What is an astronomer?A night watchman with a college education.

What do you get if you cross a student and an alien ?Something from another universe -ity !

What did the alien say when his flying saucer landed in a stud farm? Take me to your breeder !

Where do Martians drink beer ?At a mars bar !

Two aliens landed in the remote countryside and went walking from the flying saucer along a narrow lane. The first thing they saw was a red pillar box. `Take us to your leader,’ said the first alien.`Don’t waste time talking to him. Can’t you see he’s only a child?’ said the second alien.