Monthly Archives: December 2010

Q: Is Santa real?

Physicist: The existence of Santa Claus is an established fact, beyond debate.  I, like most people of my generation, have verified his existence experimentally by means of the “Cookie test”. The idea that millions of people, the world over, could … Continue reading

Posted in -- By the Physicist, April Fools, Paranoia, Physics | 13 Comments

Q: Why isn’t the shortest day of the year also the day with the earliest sunset?

The original question was: Hopefully you can help me to explain this mystery. I live in the northern hemisphere, in the U.S. I notice that winter solstice is the day with the shortest period of sunlight BUT it is not … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 17 Comments

Q: Why does “curved space-time” cause gravity?: A better answer.

Physicist: The original post is here. The curvature of space alone has almost no effect on the movement of objects until they are moving really fast.  With the exception of only the most extreme cases (black holes), space is very, … Continue reading

Posted in -- By the Physicist, Mistake, Physics, Relativity | 71 Comments

Q: According to relativity, two moving observers always see the other moving through time slower. Isn’t that a contradiction? Doesn’t one have to be faster?

Physicist: They definitely both experience time dilation.  That is to say, they both see the other person moving through time slower (you will always see your own clock running normally, in all circumstances).  The short resolution to the “paradox” is: … Continue reading

Posted in -- By the Physicist, Philosophical, Physics, Relativity | 36 Comments

Q: What does 0^0 (zero raised to the zeroth power) equal? Why do mathematicians and high school teachers disagree?

Clever student:   I know! =   = = = . Now we just plug in x=0, and we see that zero to the zero is one! Cleverer student:   No, you’re wrong! You’re not allowed to divide by zero, … Continue reading

Posted in -- By the Mathematician, Math, Philosophical | 1,158 Comments

Q: Can you do the double slit experiment with a cat cannon?

Physicist: It helps to first get an idea of how the double slit experiment is done.  The double slit experiment works for any particle, but in what follows I’ll use light to avoid confusion. Shine light on two slits separated … Continue reading

Posted in -- By the Physicist, Physics, Quantum Theory | 22 Comments