Two atoms were walking across a road when one of them said, "I think I lost an electron!" "Really!" the other replied, "Are you sure?" "Yes, I 'm absolutely positive."

Murphy's Ten Laws for String Theorists:

(1) If you fix a mistake in a mathematical superstring calculation, another one will show up somewhere else.

(2) If your results are based on the work of others, then one such work will turn out to be wrong. (3) The longer your article, the more likely your computer hard disk drive will fail while you are typing the references.

(4) The better your research result, the more likely it will be rejected by the referee of a journal; on the other hand, if your work is wrong but not obviously so, it will be accepted for publication right away.

(5) If a result seems to good to be true, it is unless you are one of the top ten string theorists in the world. (By the way, these theorists refer to their results as "string miracles".)

(6) Your most startling string-theoretic theorem will turn out to be valid in only two spatial dimensions or less.

(7) When giving a string seminar, nobody will follow anything you say after the first minute, but, if miraculously someone does, then that person will point out a flaw in your reasoning half-way through your talk and what will be worse is that your grant review officer will happen to be in the audience.

(8) For years, nobody will ever notice the fudge factors in your calculations, but when you come up for tenure they will surface like fish being tossed fresh breadcrumbs.

(9) If you are a graduate student working on string theory, then the field will be dead by the time you get your Ph.D.; Even worse, if you start over with a new thesis topic, the new field will also be dead by the time you get your Ph.D.

(10) If you discover an interesting string model, then it will predict at least one low-energy, observable particle not seen in Nature.

In summary, anything in string theory that theoretically can go wrong will go wrong, but if nothing does go theoretically wrong, then experimentally it is ruled out.

Have you heard that entropy isn't what it used to be?

Q: Where does bad light end up?

A: In a prism.

Q: How many theoretical physicists specializing in general relativity does it take to change a light bulb?

A: Two. One to hold the bulb and one to rotate the universe.

Q: What is the simplest way to observe the optical Doppler effect?

A: Go out at and look at cars. The lights of the ones approaching you are white, while the lights of the ones moving away from you are red.

Q: What did one uranium-238 nucleus say to the other?

A: "Gotta split!"

There is a sign in Munich that says, "Heisenberg might have slept here."

Ten little known facts about relativity:

(1) Nothing in the known universe travels faster than a bad check.

(2) Energy equals milk chocolate square (attributed to Albert E. Hersey)

(3) Delivery of Christmas gifts by Santa to the children of the world is now accomplished by riding Rudolf the red-shift reindeer.

(4) The general relativity theory of gravitation is responsible for people falling in love.

(5) The speed of an IRS tax refund is constant.

(6) Anger is neither created nor conserved but only changed from one form to another.

(7) The speed of time is one second per second, which is also called the fundamental unity.

(8) Death and taxes are the same for all constantly moving observers.

(9) Moving midgets are shortened.

(10) Divorce and alimony are equivalent but the latter is multiplied by an enormous factor.