40,219 reputation
355127
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 6 months
seen 4 hours ago

Experimental nuclear and particle physicist. These days I'm teaching, but I've spent a lot of time on nucleon structure in fixed target electron scattering and neutrino oscillations using reactors and beam sources.

Been reading Zemansky & Dittman's book on thermodynamics recently. Quote: ``The concept of temperature is rich in interpretations and levels of abstraction.'' Nice.


May
13
comment Is there evidence to support that the Earth has a molten core?
@user I would assume the answer is strongly frequency dependent. And perhaps amplitude dependent as well.
May
13
comment What minimum energy is required to create tracks in a cloud chamber?
Sorry, yom. That wasn't meant to be a criticism, but a minor clarification of a good enough answer that I didn't need to add a separate response.
May
13
comment What minimum energy is required to create tracks in a cloud chamber?
"beware that a cloud chamber won't observe gamma radiation." Well, unless the photon Compton scatters or pair produces (or does both repeatedly resulting in a shower).
May
13
comment Is electrons ability to produce mechanical motion considered the only reason for it to be material particle?
I still do not follow "If electron can be said to stay in place of neutron". There is no relationship between a neutron and an electron. Electrons are leptons and fundamental, neutrons are baryons and are made of quarks.
May
13
comment Time dilation. Why?
Have you browsed the dozens of other time dilation questions on the site? How are they failing to meet your needs?
May
13
comment Why don't we build helicopter based space shuttles?
Viscosity is certainly an important component in designing a lifting surface but the fundamental problem for a propeller driven system in space would be the simply lack of any reaction mass to use. Hellicopters use lift which is the reaction from pushing air the other way. Nothing to push on means no lift. That's why rockets carry their own reaction mass along.
May
13
comment Is Jefimenko's assertion regarding E and B fields a physical fact?
Related: physics.stackexchange.com/q/181277
May
13
comment What is the rigorous definition for current in a closed circuit?
For most purposes when talking about circuits you should be reasoning about current and potential, not about charge. The exception is capacitors, for which you need to know the charge in order to know the potential drop, and for those this application natural because you want to know the amount of charge added to or removed from a single side of the capacitor. If it helps think of the rule as being $\Delta q_C = \int I \,\mathrm{d}t$.
May
13
comment Is electrons ability to produce mechanical motion considered the only reason for it to be material particle?
What? That comment makes no sense.
May
13
comment How do I calculate the heat lost or gained by surroundings?
To expand on @David Zs comment, there is nothing that the site moderators are going to do. You can contact Stack Exchange (link below) and ask to have your account dissociated from this post. There is a process, but I am not sure what it looks like.
May
13
revised Is electrons ability to produce mechanical motion considered the only reason for it to be material particle?
Can't prove this. I'm sure I was told so, but...
May
13
answered Is electrons ability to produce mechanical motion considered the only reason for it to be material particle?
May
13
comment How does radiation degrade mechanical parts and electronic devices?
I have always assumed that silicon and germanium electronics are sensitive to local aberrations in the lattice structure. That is, after all, how semiconductor doping works.
May
12
comment Is there evidence to support that the Earth has a molten core?
Hmm ... good point. Not sure that I have the answer. The p-wave propagation tells us about the speed of sound in that layer, which casts some light on the density. I think that Sebastian is closer than I am there: the magnetic properties of the deep Earth combined with the density may be the strongest route but I am now officially outside of my area of competence.
May
12
comment If atoms are mostly empty space, why doesn't light pass through everything?
"Atoms are mostly empty space" This sits right near the top of my list of "Unhelpful Science Factoids That Aren't Really So". It depends on a half-assed understanding of the Bohr model which is wrong in a lot of ways, but is still taught because it is a easy stepping stone toward a real understand of atoms. However, as the de facto single thing that non-scientists "know" about atoms it is just awful and is wrong, wrong, wrong!
May
12
comment Is there evidence to support that the Earth has a molten core?
Though it is clear evidence of high temperatures underground, I'm not sure that the presence of modest quantities of molten rock in the the otherwise solid upper mantle and crust is a strong argument for large quantities of molten iron much deeper in the Earth.
May
12
comment Is there evidence to support that the Earth has a molten core?
Nice and more complete than my quickie answer.
May
12
comment Is there evidence to support that the Earth has a molten core?
Finally, I will more this question to Earth Science if you'd like, but I read it as on-topic on Physics if you would rather it stayed here.
May
12
comment Is there evidence to support that the Earth has a molten core?
Here's a hint: asking "is there evidence" for things that have been established scientific fact for decades could be interpreted as suggesting that people are making this stuff up as the go along. Much better to ask what the evidence is.
May
12
answered Is there evidence to support that the Earth has a molten core?