Category Archives: Particle Physics

Q: What are Feynman diagrams, how are they used (theoretically & practically), and are there alternative/competing diagrams to Feynman’s?

Physicist: Feynman diagrams are primarily a way to keep track of what you’re doing.  Physicists aren’t geniuses or anything, and they get distracted pretty easily. When you’re trying to calculate the probability of a particular particle interaction you’ll find yourself … Continue reading

Posted in -- By the Physicist, Combinatorics, Equations, Particle Physics, Physics, Quantum Theory | 11 Comments

Q: Why can’t you have an atom made entirely out of neutrons?

Physicist: The short answer is; you probably can, but not for long. If you’ve taken a little chemistry you probably know that the electrons in an atom “stack up” in energy levels.  The more electrons you add, the higher the … Continue reading

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

Q: Why does energy have to be positive (and real)?

The original question was: I was reading an article about tachyons in Wikipedia and stumbled upon this sentence: “Because the total energy must be real then the numerator [mc^2] must also be imaginary”.  I’m confused by the fact that in … Continue reading

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

Q: If gravity is the reaction matter has on space, in that it warps space, why do physicist’s look for a gravity particle? Wouldn’t gravity be just a bi-product of what matter does to space?

Physicist: Isn’t that weird? The name “quantum mechanics” comes from the fact that, at its most base, quantum mechanics requires all particles and energies to come in discrete (one might say “quantized”) packets.  At some point a bunch of physicists … Continue reading

Posted in -- By the Physicist, Particle Physics, Physics, Quantum Theory | 12 Comments

Q: Do virtual particles violate the laws that energy can be created or destroyed? Have virtual particles ever been observed? In any other instance can energy ever be destroyed or created?

Physicist: Almost. There’s a version of the uncertainty principle that says that the amount of energy and the amount of time involved in an event can’t both be certain.  You can think of this version of the uncertainty principle as … Continue reading

Posted in -- By the Physicist, Particle Physics, Physics, Quantum Theory | 6 Comments

Q: Is it true that all matter is simply condensed energy?

The complete question was: Is it true that all matter is simply condensed energy? Does that mean that the Big Bang was pure energy and coalesced into matter? Physicist: Pretty much.  If you can get enough energy into one place … Continue reading

Posted in -- By the Physicist, Particle Physics, Physics, Quantum Theory | 33 Comments