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I am a graduate student studying astrophysics at Princeton. I received my bachelor's in physics and mathematics from Caltech (2011).

My primary interest is in general relativistic magnetohydrodynamics simulations of black hole accretion.


Oct
31
comment Example for bias in experiments due to “social pressure”
This could easily describe the Hubble constant as measured by Hubble himself (way off initially, since his data was pure noise), or the electron charge as measured by Millikan (he was slightly off but considerably underestimated his uncertainties), or probably a ton of other examples.
Oct
31
comment Gravity and Larmor effect
Before introducing gravity, one should first ask "Does a constantly accelerating charged particle emit em radiation or not?" in flat spacetime. As you can read there, it is not clear that the Larmor formula even applies, and one has to be extremely careful about defining what it means to radiate.
Oct
31
comment Elliptical orbits passing 2 points
This question appears to be off-topic because it is about pure math (finding the solutions, try math.stackexchange.com), symbolic manipulation (simplifying the solutions, try mathematica.stackexchange.com, or stackoverflow.com for a different language), and numerical efficiency (coding the solutions, try scicomp.stackexchange.com), but not physics.
Oct
31
comment Do primordial background neutrinos orbit in dark matter halos?
How timely. This paper, Neutrino clustering around spherical dark matter halos, was put on the Arxiv just a week ago. I think the short answer is "there is a small but nonvanishing amount of neutrinos." Perhaps someone can use this or some other paper as a launching-off point for a complete answer.
Oct
31
comment What is the depth in meters of the pond?
@akusaja A basic overview is here. A more thorough guide covering many more features is here.
Oct
30
comment current in wire + special relativity = magnetism
First question: Yes. Second question: You have to be consistent which frame you are in, and you have to specify which frame has the neutral wire. In the test-charge-stationary frame in Case 3, I assume there is a current but the wire is neutral, as is often the case in laboratory setups. You can't assume the wire is neutral in some other frame - that would be a contradiction. If you want to change to another frame, you have to do 3 things: find the new speed of the test charge, find the charge of the wire, and find the current in the wire. Then apply Lorentz.
Oct
29
comment Does someone falling into a black hole see the end of the universe?
I have a small but important objection to this argument (cc @John Rennie): If our coordinates inadvertently expanded a point (in 1+1D) to a line, then hitting different parts of the line doesn't mean the trajectories don't converge. Consider maps of Earth that expand the North Pole to a horizontal line - you wouldn't say someone at (90 N, 20 E) is disconnected from someone at (90 N, 130 W), even though the diagram implies it. Similarly, the point where my worldline intersects $u=v$ looks disjoint from where some null ray intersects this line, but you need to prove that they are distinct.
Oct
29
comment Divergence of series
@ShaonaBose We're actually somewhat confused why math.SE rejected the question, too. I suggest posting a new question there (make no mistake, this is a math question, not a physics one, regardless of what context it appeared in), maybe expanding a little on what you've tried or tinkered with. At the very least, if it's closed again they'll have to give a reason and you can work with them to get the question up to their standards.
Oct
29
comment Integrating Radial Vector Fields
This is all well and good, so +1, but do you think the OP was really supposed to just examine the parity of $\vec{r}$ and $\rho$ over a spherically symmetric domain? Unless I'm mistaken, the answer needs no integration at all, right?
Oct
26
comment How accurate are Mayan astronomical “ephemerides”?
The Sun's path across the sky is pretty much the same during this equinox and an equinox 1000 years ago - it doesn't take any sophisticated knowledge to have the same rough shadows appear year after year.
Oct
23
comment Dipping a Dyson Ring below the event horizon
As I've noted here, defining event horizons in terms of escape velocity is actually wrong, but people do it anyway because it coincidentally gets the right answer. The event horizon is defined topologically, as the surface inside of which nothing can ever escape "to infinity."
Oct
18
comment Why the center of our galaxy doesn't absorb us?
Spiral arms are density waves, not streams of matter being sucked into the center. See for instance How do spiral arms form? and How can a spiral galaxy exist?
Oct
17
comment The example of relativity of simultaneity given by Einstein
@user1688944 I'm not sure I catch your meaning. In 1D, if two events are simultaneous for one observer, they are necessarily not simultaneous for anyone moving with respect to that observer. But in more dimensions you can get around this by moving relative to the first observer but orthogonal to the line connecting the two events.
Oct
17
comment Ionization Energy and Bohr
@Anonymous Exactly. There are $n = 1$ electrons, but usually they're not the ones we're trying to remove.
Oct
15
comment Historical reason behind using $ν$ instead of $f$ to stand for frequency in the equation $E=hν$?
Interesting fact: Both de Broglie in his 1925 thesis (pdf) and Planck in his 1900 paper where he gives his eponymous relation (pdf) use $\nu$ for frequency, despite both French and German using words that begin with "f." Actually, Planck doesn't use the word "Frequenz" at all as far as I can tell, preferring instead "Schwingungszahl" or "Spectralbezirk."
Oct
15
comment Historical reason behind using $ν$ instead of $f$ to stand for frequency in the equation $E=hν$?
Moreover, 99% of the time in physics $\omega = 2\pi \nu$. The difference is just whether one is dealing with radians or cycles.
Oct
14
comment The example of relativity of simultaneity given by Einstein
@user1688944 Basically yes. If you see two flashes simultaneously, you know each flash's distance from you (in your frame) equals $c$ times the time elapsed since it went off (in your frame). Nonzero relative velocity generically implies a disagreement on elapsed time, and thus a disagreement on distances. However, at least in 1D, this would lead to a contradiction if the observers were forced to see both flashes at the same point in spacetime, as the symmetry of the situation means boosts to other frames should keep the distances equal as they change.
Oct
14
comment What are the demographics of stars visible to the naked eye?
The overall scaling @Kitchi refers to is discussed here, and in particular this answer cites a source for the 6000 (though that source could stand to be clearer on their methods).
Oct
11
comment How does electricity 'decide' on it's pathway?
Also related: physics.stackexchange.com/q/28311
Oct
10
comment Why can't Iron fusion occur in stars?
Related: What elements can be created in the fusion process of different types of suns? The full answer to this question, though, will need a good deal of stellar structure to explain.