Brent D. Nelson: PhysLink.com Expert

   Brent D. Nelson
Brent D. Nelson
M.A. Physics
Physics Ph.D. Student
UC Berkeley, CA 		Questions answered
to date:
30
Biography Brent Nelson was born in San Jose in 1971 and has received his B.A. in physics and in economics from UC Berkeley in Dec. of 1993. After working for a litigation consulting firm for a couple of years he returned to graduate school in 1995. He is now entering his fifth year and is nearly finished with his physics Ph.D.

He is currently working on elementary-particle theory topics. In particular he is interested in the phenomenology of string theory, supergravity models and cosmological issues such as inflation, dark matter and baryogenesis.

You can get more information about his research by visiting his research group web site.

Published Answers All answers by Brent Nelson published at PhysLink.com up to date are listed here:
  1. Why does increased pressure lower the melting point of ice? Can we use the First Law of Thermodynamics to explain?

  2. Please can you (briefly) tell me how the concept of 'non locality', or what Einstein referred to as 'spooky action at a distance' was arrived at?

  3. What is a quark?

  4. What is the string theory? Who came up with it / discovered it?

  5. I have found a photo of a famous scientist by the last name of Cronin. For what was he famous?

  6. Why is there no color spectrum at the sub-atomic level? Or is there?

  7. What is the significance of the number 137 in physics?

  8. Why isn't the electron considered a black hole? It does have mass and its radius is infinitely small, isn't it?

  9. I heard from a friend recently that a new 'type' of matter has been detected at CERN: neutralinos. Is that true?

  10. What is meant when one says that the temperature of the cosmic background radiation is 3K?

  11. By what method is the size (or volume) of the universe at the moment of the big bang (or shortly thereafter) determined? Related to this, how is the size of a black hole determined?

  12. On the atomic level, there is some free space between the electrons and nucleus of atoms (and between the protons and neutrons in the nucleus itself). What 'material' fills these spaces? Dark matter?

  13. Does the universe have a total angular momentum?

  14. Is there any experimental data supporting the existence of gravitons? If there is, how fast do these wave/particles travel? Are they similar to photons?

  15. If there is anti-matter, couldn't there be anti-energy?

  16. I heard that 'bosons' are particles made from a quark and an anti-quark. Is this true? If it is, then how come they do not to annihilate each other?

  17. What is singularity and why do all laws of physics break down at singularity?

  18. What is cosmic radiation? Is it dangerous?

  19. How can something have a negative mass, and what does that mean?

  20. Say you have a twin, and you go off into space, traveling near the speed of light, when you return, will your twin have aged more?

  21. The Second Law of Thermodynamics states that the universe tends toward high entropy. If so, what happens when there is nothing left to be disordered? How can matter be constant?

  22. What are Feynman diagrams? Could you give good bibliography about QED?

  23. Since oppositely charged particles attract, and gravity is a phenomenon common to all particles, how come the electron is not 'sucked' into the nucleus?

  24. What does the term 'strangeness' refer to?

  25. How does a boomerang work?

  26. Where are the Pioneer and Voyager space probes? Are they still operating? Is anybody listening to them?

  27. Have gluons actually been detected, and if they have, how?

  28. Could someone please explain to me the difference between a Type 1 Nova, and a Supernova?

  29. From what I understand, Planck time is the amount of time it takes a photon to move Planck length, but what is Planck length and what is it based on?

  30. Foods can be sterlised by passing gamma radiation through it. Why is it still safe to eat? Won't it become radioactive?