Category Archives: Physics

Q: What is the evidence for the Big Bang?

Physicist: The very short answer is: all the galaxies in the universe are flying apart, so at some point in the distant past they must have been very close together.  It would have been so close and so dense that … Continue reading

Posted in -- By the Physicist, Astronomy, Physics | 13 Comments

Q: What is going on in a nuclear reactor, and what happens during a meltdown?

Physicist: Nuclear reactors are very 19th century in a way. The nuclear fuel is basically a bunch of very hot metal, and the more of it you get together in one place, the hotter it gets.  That heat is used … Continue reading

Posted in -- By the Physicist, Engineering, Particle Physics, Physics | 10 Comments

Q: Are all atoms radioactive?

The original question was: Some elementary particles spontaneously break apart at a given rate. Can the same be said about normally stable atoms and molecules? That is, even though they are stable, does their natural internal activity lead to a … Continue reading

Posted in -- By the Physicist, Particle Physics, Physics, Quantum Theory | 5 Comments

Q: Why does E=MC2 ?

Physicist: It’s a little surprising that this question didn’t come up earlier.  Unfortunately, there’s no intuitive way to understand why “the energy of the rest mass of an object is equal to the rest mass times the speed of light … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 82 Comments

Q: What are the equations of electromagnetism? What all do they describe to us?

Physicist: Electromagnetism and all the involved math are surprisingly visual sciences.  Understanding Maxwell’s equations (the equations of electromagnetism) involves pictures aplenty. In these equations and are physical constants that dictate how strong the electric and magnetic forces are, but when … Continue reading

Posted in -- By the Physicist, Equations, Physics | 14 Comments

Q: How can quantum computers break encryption?

Physicist: What follows is the famous Shor algorithm, which can break any RSA encryption key. The problem: RSA, the most common form of public key encryption, is based on the fact that large numbers are hard to factor.  Without going … Continue reading

Posted in -- By the Physicist, Computer Science, Equations, Math, Number Theory, Physics, Probability, Quantum Theory | 19 Comments