25,991 reputation
162134
bio website lightandmatter.com
location Fullerton, California
age
visits member for 3 years, 4 months
seen 2 days ago

I teach physics at Fullerton College, a community college in Southern California. I have an undergrad degree in math and physics from Berkeley and a PhD in physics from Yale. Back when I was doing research, my field was experimental low-energy nuclear physics.


20h
awarded  Good Question
23h
awarded  Enlightened
1d
awarded  Nice Answer
2d
awarded  Nice Answer
2d
awarded  Nice Answer
Nov
22
comment Would a wormhole in space look like anything at all?
@GreenAsJade: Intense radiation inside the wormhole is a standard prediction. I don't know enough about QFT on a curved background to be able to give you a clear explanation.
Nov
21
comment Would a wormhole in space look like anything at all?
What you're saying makes sense to me. I would also probably expect a wormhole to emit a lot of nasty ionizing radiation, since that's what's normally expected to destroy objects passing through.
Nov
21
revised Poynting vector plane wave
spelling
Nov
21
comment Definition of the quality $(Q)$ factor?
Why the downvote?
Nov
21
comment How far has a 13.7 billion year old photon travelled
@PetTaxi: The proper length is zero, because the photon's path is lightlike. If you want to define the photon's "odometer," you can't do it in the photon's frame, because a photon doesn't have a rest frame. The 13.7 byr is measured on a clock that's at rest relative to the Hubble flow. The 13.7 blyr is measured on a chain of rulers, each at rest relative to the Hubble flow.
Nov
21
answered Definition of the quality $(Q)$ factor?
Nov
21
comment How to relate the height from which a object can fall with the young modulus of that object?
possible duplicate of The maximum height to wich the center of gravity of the person can perform the fall without breaking the femur bone?
Nov
21
revised The maximum height to wich the center of gravity of the person can perform the fall without breaking the femur bone?
redo homework-and-exercises tag, which OP took out
Nov
21
comment Do consciousnesses get “scattered” across the many worlds of the MWI?
MWI doesn't really have branching. physics.stackexchange.com/questions/32501/… . MWI just says there's a wavefunction, and it evolves unitarily. Branching may be an appropriate, approximate description in some cases.
Nov
21
revised The maximum height to wich the center of gravity of the person can perform the fall without breaking the femur bone?
edited tags
Nov
21
comment What is wrong with the Bohr model?
It predicts that the hydrogen atom is flat rather than spherical. It predicts the wrong angular momenta, e.g., $L=1\hbar$ for the ground state rather than the correct $L=0$.
Nov
21
comment How to theoretically define a concrete operation to perform in order to measure the length of an object?
@bobie: does your post answer the OP question? Yes, it does. See the paragraph beginning with "Einstein synchronization..."
Nov
21
comment How to theoretically define a concrete operation to perform in order to measure the length of an object?
@user12262 and bobie: You might benefit from reading the linked article on operationalism.
Nov
21
awarded  Necromancer
Nov
21
comment Why is the energy of particles in accelerators much higher than the energy of the particles they are trying to find?
The multiplicity of charged hadrons produced in pp collisions at the LHC seems to be $\sim100$: dspace.mit.edu/handle/1721.1/68876 . If you're producing on the order of a hundred particles, maybe it makes sense that you have to put in on the order of a hundred times the energy of the particle you're hoping to create.