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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.


Nov
27
comment Why does rotation simulate gravity if motion is relative?
Some historical background: Einstein was inspired by Mach's philosophy (which is not to say general relativity is necessarily 100% Machian), which in turn mirrored much of what Leibniz believed. Newton and Leibniz vehemently disagreed on a number of things (not just calculus), one of which is whether a notion of space exists independent of the matter in the universe. To counter Leibniz's "everything's relative" stance, Newton put forth his bucket thought experiment, which, as far as I know, none of his contemporaries had a good response to.
Nov
26
comment Formation of supermassive black holes
I'd add that we can adjust parameters for various models for the growth and mergers of these black holes, and this can lead to either underpredicting or overpredicting their abundance. So it's not a situation of "we can't explain where they come from" but rather "there are many ideas that work, we're not sure which most accurately depicts reality."
Nov
25
comment How does the second law of thermodynamics follow from low entropy of early universe?
@Sofia You've highlighted the usual story that gets told, which is what this post is (rightly) questioning. The common story is "entropy was very low in the early universe, so it has generally increased." But that has essentially nothing to do with with a glass shattering when I drop it. And certainly if the universe were to start contracting I would still expect my glass to shatter, not to reassemble itself.
Nov
25
comment Fluid dynamics - immiscible liquids
That discussion can be found in many threads on meta. In particular check out Bite-sizing homework. I think it's fair to say we struggle with trying to filter out people trying to get us to do their work for them (we're not interested, and it only hurts the students, and it's unfair to everyone else in the class), but at the same time be useful as a resource for students whose questions are inspired by their homework (as good homework tends to inspire further questions).
Nov
25
comment Fluid dynamics - immiscible liquids
The close votes so far are all in reference to the homework policy. I actually think this isn't necessarily in violation of the policy, but I could see arguments either way. Know that many veterans of this site have grown weary with the flood of homework, and we see too many "but I even showed all my work, why not tell me where I'm wrong?" complaints (missing the fact that there must be a concept there too), so questions that look vaguely like "<problem> <work> <what went wrong?>" provoke a negative reaction.
Nov
24
comment Is it possible to make laser beams visible midair without smoke?
Since ultimately you want a screen-like display, not just a visible laser, I'll only leave this as a comment. Even in clean air a visible laser (green works well) will backscatter off particles, making the beam visible particularly from behind. I use a 35 mW green laser for astronomy demonstrations all the time. At night the beam can be seen hundreds of feet into the air. At the same time it's worth pointing out that, as cool as they are, lasers are not always the best technology for the job.
Nov
24
comment From a particle's point of view is his temperature absolute zero
I'm going to vote to reopen on the basis that the Lorentz scalar nature of $T$ is a red herring -- as Ben Crowell points out, the fundamental problem is a statistical one in that $T$ isn't defined for one particle. The proposed duplicate still deals with bulk collections of particles.
Nov
24
comment What does this depiction of a black hole in the movie Interstellar mean?
My instinctive reaction as someone who simulates black hole accretion is to be rather skeptical about the scientific novelty. Ray tracing has been done before; it's not that hard to trace geodesics even in Kerr spacetime. The real action is simulating the dynamics of the disk and the formation of a jet.
Nov
5
comment Topological implications of symbolic represenation of the relativity
Just my 2 cents: People should have stopped using $i$ in relativity in 1916, since it doesn't work in GR. But some people still use 98-year-old ideas today, so an answer is providable here. (That answer being essentially "there is nothing good that comes from using $i$, and it doesn't even work in general.") Thus I voted (with no strong feelings) to keep open.
Nov
4
comment Difficulties in understanding basic energy equation in quantum mechanics
While the question may be based on a mistake, it is asked in good faith and is certainly answerable, so I don't see why it is off topic.
Nov
3
comment Where do Newton's laws come from?
possible duplicate of What in Newtons three laws of motion original to himself and not a paraphrasing of his predecssors See also History of interpretation of Newton's first law, How did Newton discover his second law?, How did Newton discover his third law of motion?
Nov
3
comment Manager for results of physical simulations
You know, as projects scale up the work required to set up the software pipeline becomes comparable to the work needed to write the simulation code/design the telescope/build the particle collider. And alas these are usually quite specialized; I'm not aware of any "pipeline infrastructures" out there.
Nov
2
comment How do control rods work?
In case the terminology isn't clear to someone not in the field, I'd add that "thermal" means having a Maxwellian distribution of speeds, usually with a temperature of something room temperature. That is, the gas of free neutrons approaches thermodynamic equilibrium with everything else in the reactor, in this case by slowing down ("thermal" does not always mean "hot").
Nov
2
comment Measuring small amounts of lift in a wind tunnel
For the record, I think off-topic by way of engineering is meant to exclude "what is the most cost-effective way to manufacture this?" questions, not "how do I perform a physical measurement?" questions.
Oct
29
comment Calculating vector to aim for moving asteroid (3D asteroid game)
@Bradley My (4) is just a way of writing your statement "our ship can shoot bullets, the speed of which is known" -- I write that known speed as $v$, and in my notation the vector $\dot{\mathbf{A}} = (\dot{A}_x, \dot{A}_y, \dot{A}_z)$ is just the velocity vector for the bullet. $\lVert \dot{\mathbf{A}} \rVert = v$ is the fundamental constraint equation, but this is easier to write by squaring both sides.
Oct
28
comment What mechanism is responsible for the creation of these dunes on Comet 67P/Churyumov-Gerasimenko?
Note to potential answerers who assume, like I originally did, that this is sand: It was pointed out to me that we have observed other bodies to consist of larger rock fragments (think fist-sized stones, I'll see if I can dig up a reference), and at this resolution that would look the same as sand. So these may be large pebble dunes rather than sand dunes.
Oct
28
comment Is any energy required to deflect an asteroid, with force always perpendicular to its trajectory?
I'm confused. You talk about straight lines and lack of gravity, then you talk about centripetal forces. Which is it?
Oct
28
comment What's so special about the speed of light?
@WetSavannaAnimal I haven't completely settled on my opinion, perhaps because I've only taught at the pre- or post-SR level. I do love the abstract approach like in your answer, especially since I think the main alternative of teaching relativity via "paradoxes" is counterproductive (and often just a form of showing off to the unlearned - "Look how weird physics is, but I understand it!"). On the other hand, there are all those useful thought experiments that rely on bouncing light back and forth between mirrors.
Oct
27
comment What's so special about the speed of light?
I actually think it is not a duplicate, despite the identical title.
Oct
23
comment Center-of-mass frame for massless particles
And this is why various authors say "center-of-momentum frame" instead, where conveniently/confusingly it has the same acronym.