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bio website lightandmatter.com
location Fullerton, California
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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.


Nov
19
comment Gravitational Redshift and Length Contraction
Length contraction doesn't have anything to do with the metric.
Nov
19
comment Is it possible to prove that units can be manipulated algebraically?
Re the final paragraph, Leibniz notation is designed to make it manifest that when you differentiate or integrate, the dimensional validity of the equation remains valid at every step. For example, in $\int v dt$, the units work out to be distance if you take $dt$ to have units of time.
Nov
19
comment No-hair theorems for naked singularities?
@zibadawatimmy: He's saying that if you take the Kerr–Newman metric and put in the mass and charge of an electron, you get a naked singularity. That doesn't mean that an electron is a naked singularity.
Nov
18
comment What's the escape velocity of Naked Singularities?
In the non-naked $Q=0.4$ case, is it really meaningful to talk about escape velocities at $r<0.2r_s$? For example, a ray of light from this region can't actually escape to infinity, can it? Wouldn't it would rise outward but fall back in before reaching the inner horizon?
Nov
18
comment What's the escape velocity of Naked Singularities?
If I'm understanding the analysis correctly, doesn't this mean that for this type of naked singularity, this analysis fails to determine an escape velocity from the singularity, which I assume is at $r=0$?
Nov
18
comment Why are the dineutron and diproton unbound?
If you want to salvage your old text for a new question, you can look at the edit history by clicking on "edited x minutes ago."
Nov
18
comment Why are the dineutron and diproton unbound?
OK, sorry if I messed up what you wanted. However, I think that would be better if it was separate from the question of why the dineutron and diproton are unbound. How about asking your quantitative question about $U(r)$ as a separate question? But actually the answer is not going to be well defined, for the reasons described in my answer to the qualitative question.
Nov
18
revised Why are the dineutron and diproton unbound?
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Nov
18
answered Why are the dineutron and diproton unbound?
Nov
18
revised Why are the dineutron and diproton unbound?
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Nov
18
comment Why are the dineutron and diproton unbound?
This seemed like two separate questions, and one of the questions was a duplicate of this one: physics.stackexchange.com/questions/78107/… Therefore I've taken the liberty of editing out that part to focus on the other part. Hope that's OK with you.
Nov
18
answered Why inversion of wave for rope fixed at one end?
Nov
18
answered Can time be calculated without actually involving any matter?
Nov
18
comment Is the observable universe growing or shrinking?
In a matter-dominated universe, more objects are always coming inside the horizon, but in a universe dominated by dark energy it's the other way around. Our universe is transitioning from matter-dominated to dark-energy-dominated, so at some point things will stop coming in and start going out, but I think that hasn't happened yet.
Nov
18
revised Are Wormholes predicted by the theory of general relativity?
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Nov
18
revised Are Wormholes predicted by the theory of general relativity?
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Nov
18
revised Are Wormholes predicted by the theory of general relativity?
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Nov
18
answered How to theoretically define a concrete operation to perform in order to measure the length of an object?
Nov
18
revised How to theoretically define a concrete operation to perform in order to measure the length of an object?
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Nov
18
comment No-hair theorems for naked singularities?
@zibadawatimmy: Jerry Schirmer is correct. You're interpreting his statement incorrectly.