Monthly Archives: January 2012

Q: Why does gravity make some things orbit and some things fall?

Physicist: This subtlety was one of the great insights of Newton; that the “falling apples” force and the “circling planets” force are one and the same. Whether gravity pulls an object into orbit or just “makes it fall” depends on … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 11 Comments

Q: Do you need faith to believe in science?

Mathematician: This question could mean a few different things, depending on what is meant by the word “faith.” Let’s start with the dictionary definitions. 1. Strong belief in God or in the doctrines of a religion, based on spiritual apprehension rather than … Continue reading

Posted in -- By the Mathematician, -- By the Physicist, Philosophical, Skepticism | 27 Comments

Q: What keeps spinning tops upright?

Physicist: That’s a really tricky question to answer without falling back on angular momentum.  So, without getting into that: Gyroscopes, tops, and everything that spins are seriously contrarian dudes.  If you try to rotate them in a direction that they’re … Continue reading

Posted in -- By the Physicist, Physics | 6 Comments

Q: Do time and distance exist in a completely empty universe?

Physicist: This is a classic philosophical question! For a while, it was generally assumed that without matter distance and time would still exist.  After all: why not?  Time is time and space is space, and the material things in them … Continue reading

Posted in -- By the Physicist, Philosophical, Relativity | 19 Comments

Q: Why is it that photographs of wire mesh things, like window screens and grates, have waves in them?

Physicist: There are two major effects that generate waves in pictures. The first is called “aliasing”, and it’s caused by “under-sampling”.  It shows up every now and again when you’re using a digital camera, or when you’re trying to express … Continue reading

Posted in -- By the Physicist, Math | 3 Comments

Q: How does quantum physics affect electron configurations and spectral lines?

The original question was: I recently got a book about all the chemical elements and noticed how some have a lot of lines of spectra and others hardly any.  I was wondering what exactly causes the lines of spectra to … Continue reading

Posted in -- By the Physicist, Physics, Quantum Theory | 10 Comments