Category Archives: — By the Physicist

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

Posted on October 29, 2012 by The Physicist

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 | 12 Comments

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

Posted on October 24, 2012 by The Physicist

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 | 14 Comments

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

Posted on October 20, 2012 by The Physicist

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 | 11 Comments

Q: Does opening a refrigerator cool down the room?

Posted on October 15, 2012 by The Physicist

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 | 32 Comments

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

Posted on October 10, 2012 by The Physicist

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 | 11 Comments

Q: Why are the days still longer than nights, until a few days after the fall equinox?

Posted on September 29, 2012 by The Physicist

Physicist: The issue here is the equinoxes are the two days of the year when the length of the day should be exactly as long as the night.  And yet you’ll find that on the equinox the day is always … Continue reading →

Posted in -- By the Physicist, Astronomy, Physics | 2 Comments