Jerry Schirmer

Austin, TX

Age: 34

I am a Ph.D. general relativist working as a software engineer. I like to still go and do physics as a hobby, and to keep up my skill and knowledge.

6h
answered Why does gravity enact force?
7h
answered Density distribution of black hole while cycling energy?
7h
comment Gravity - Force or Result?
@CuriousOne: not everyone thinks that gravtons exist? Who doesn't think that gravitational waves should have quanta in some fundamental theory? There's no known way to couple classical degrees of freedom to quantum degrees of freedom, and the black hole entropy stuff is screaming that there needs to be some sort of quantization of gravity.
1d
comment Why do we believe in a "force" driven universe?
They're likely to be harsher on physicsoverflow, but feel free to give it a try. It's a much slower place over there.
1d
comment Why do we believe in a "force" driven universe?
@AlistairRiddoch: we're not invested in these paradigms, so much as they work, and they explain a ton of unexpected things. In each instance, they're actually simpler than what came before, as you can really easily see formulating electrodynamics with and without special relativity, for instance.
1d
answered Why do we believe in a "force" driven universe?
1d
comment Understanding fields and their correlation to forces
@Key: fundamentally, all magnetic forces are due to the Lorentz force on moving charges. Even ferromagnets have their roots in the spinning of charged electrons.
Oct
16
comment How much energy does a photon need to form a black hole?
@CountIblis: LQG quantizes area at the planck scale, so I would assume that you lose Lorentz invariance at similar length scales.
Oct
16
comment How much energy does a photon need to form a black hole?
@21joanna12: there is no answer in LQG yet. The theory, as it currently exists, is a theory of gravity alone. There is no matter content in it, and thus, no concept of "a photon" in a full, quantum sense.
Oct
16
answered How much energy does a photon need to form a black hole?
Oct
15
comment Bose Einstein condensates and gravity
For instance, it is pretty trivial to create a recollapsing cosmology containing only radiation.
Oct
15
comment Bose Einstein condensates and gravity
@LucaMingarelli: light has a nonzero stress-energy tensor, and therefore, a nonzero gravitational field.
Oct
13
answered Kaluza suggested metric
Oct
13
comment Why does Venus rotate the opposite direction as other planets?
Almost all bodies lie on the plane of the ecliptic, any collision was likely with another body also on the ecliptic, so a collision is unlikely to change the orientation of any planet, only the amount of spin.
Oct
10
comment Modifying Newtonian gravity to fit observed precession of Mercury's orbit
@DeinFreund: If you're going to model the precession of Mercury, you can look into the Post-Newtonian formalism. It's basically a trick to approximate GR in a weak-field limit. For solar system stuff, you really only need the first couple of terms.
Oct
10
comment Modifying Newtonian gravity to fit observed precession of Mercury's orbit
@KyleKanos: MOND would be an acceleration-dependent effect.
Oct
10
comment Modifying Newtonian gravity to fit observed precession of Mercury's orbit
Are you trying to add general relativistic effects to Newtonian theory, or are you trying to empircally model the motions of the planets? Are you only considering the effects of the sun, or are you also considering planet-planet effects?
Oct
9
comment Storing a Planet-sized Chunk of Metal Inside a Star
In an ordinary star, only the Hydrogen will fuse--the pressures and temperatures for helium fusion are much higher than those for hydrogen fusion, and this will not happen, for the most part, until the hydrogen in the core is exhausted. Of course, for anything heavier than iron, fusion will be endothermic, and will not happen spontaneously.
Oct
9
comment What's the meaning when Kerr-Newman metric's mass is zero?
@CuriousOne: it's easy enough to study the zero mass Nordstrom spacetime. I have no idea about how the central singularity behaves in that case.
Oct
8
comment jumping into water
I thought that the main reason that breaking the water in front of you was that it broke the surface tension, not that it spaced out your deceleration over a greater distance. Hence why olympic pools will release air bubbles from the bottom ahead of high divers.
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