Astronomy?

In honor of the discovery of a new planet in our solar system, here are some jokes:

1. What does an astronomer use to hold up his pants?
2. Where does an astronomer go for a higher education?
3. Did you hear the joke about astronomy?
4. How do you keep astronomers clean?

Answer the questions in the comments if you think you are clever enough... I'll acknowledge the correct answers as posted or post the correct answers tomorrow pm in the comments.

Some miscellaneous facts:

• Some time during the 300's BCE, Aristotle of Greece created an Earth-centered model of the universe that used 56 concentric spheres. The earth, sun, moon, and planets occupied different spheres. The outermost sphere was where the stars were located. The model of the universe where the Earth rotated around the Sun was first developed by Aristarchus of Greece around 300 BCE.
• Around the year 150, Ptolemy of Greece perfected a view of the universe with Earth at it's center. Ptolemly's Earth-centered universe was accepted for nearly 1500 years.
• In the early 1500's, Nicolas Copernicus of Poland developed a model of the universe where the Sun was the center of the universe
• Galileo was jailed in the 1600's for supporting Copernicus' idea that Earth was not the center of the universe and actually rotated around the Sun.
• Astronomers in China, Egypt, and Mesopotamia tracked the movements of the sun, moon, and planets more than 3,000 years ago.
• Stars appear to twinkle because the moving atmosphere of our planet causes the light from the star to be bend slightly.