On 15 August 2000, The New York Times, celebrating the new century, published a list of 10 questions that they characterized as ones physicists would like to ask their colleagues in the year 2100 if they awoke from a hundred-year sleep.

1. Are there reasons why the fundamental dimensionless parameters have the values they do?

2. What role did quantum gravity play in the Big Bang?

3. What is the lifetime of the proton?

4. Is supersymmetry a broken symmetry of nature?

5. Why is spacetime apparently four-dimensional?

6. What is the value of the cosmological constant, and is it really constant?

7. Does M-theory describe nature?

8. What happens to information that falls into a black hole?

9. Why is gravity so weak?

10. Can we quantitatively understand quark and gluon confinement?

You will not be surprised to learn that the questions were assembled at a party celebrating the conclusion of a conference on superstring theory. The Times, however, characterized them as “Physics questions to ponder,” leaving me to ponder why they were so different in character from what I would be most eager to learn from my professional descendants at the end of a hundred-year nap.

The Times inspired me to put together my own list of the questions I'd put to a colleague in 2100. The criteria for inclusion on my list are (a) that I would love to know the answer, (b) that the questions should be likely to make sense to scientists in 2100 and not just to historians of science, and (c) that the questions should have a reasonable chance of not eliciting titters at my early 21st-century naivety. Probably you'll find my list just as parochial as I found the string theorists’ list. But here it is: