Monthly Archives: October 2012

Q: How accurately do we need to know π? Is there a reason to know it out to billions of digits?

Physicist: For essentially every imaginable purpose, knowing that π ≈ 3.14159 is more than good enough.  After all, every additional digit you have yields ten times the accuracy.  So if you know π out to twenty digits, that’s not 20 … Continue reading

Posted in -- By the Physicist, Math | 8 Comments

My bad: If fusion in the Sun suddenly stopped, what would happen?

Physicist: A commenter from the original post was kind enough to point out a massively bone-headed mistake.  My bad.  In the calculation to figure out how long it would take the Sun to cool I had used Fourier’s law of … Continue reading

Posted in -- By the Physicist, Mistake | 11 Comments

Q: If fusion in the Sun suddenly stopped, what would happen?

Physicist: Almost nothing.  We’d have plenty time to pack our bags and leave. Assume that the cause of the fusion-stopping doesn’t matter, maybe the Weak force suddenly changed, or maybe the Vorgons used the Tax Uthat on the Sun, or … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 8 Comments

Q: Does opening a refrigerator cool down the room?

Physicist: Briefly yes, or no, not at all.  If you think of the room as including the inside of the refrigerator, then opening the door does nothing.  Otherwise, it does almost nothing.  But ultimately, if you leave the door open … Continue reading

Posted in -- By the Physicist, Engineering, Entropy/Information, Physics | 17 Comments

Q: What is the probability of an outcome after it’s already happened?

Physicist: There are a lot of subtleties to this.  Reading the question, your gut reaction should be “Duh, it’s 100%!  Wait, is this really a question?”. And yet, there are many times in which you may find yourself estimating probabilities … Continue reading

Posted in -- By the Physicist, Philosophical, Probability, Quantum Theory | 8 Comments

Q: How do you answer a question scientifically?

Mathematician: Suppose you’re interested in answering a simple question: how effective is aspirin at relieving headaches? If you want to have conviction in the answer, you’ll need to think surprisingly carefully about how you approach this question. A first idea … Continue reading

Posted in -- By the Mathematician, Math, Philosophical, Probability | 2 Comments