23,087 reputation
44989
bio website
location Princeton, NJ
age 25
visits member for 2 years, 4 months
seen 5 hours ago

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.


Dec
2
comment Projection operators in a direct product space
This is a common mistake in terminology: the direct product $\times$ is more akin to the direct sum $\oplus$; what you have is the tensor product $\otimes$. One important difference is that $\dim(A\oplus B)=\dim(A)+\dim(B)$, while $\dim(A\otimes B)=\dim(A)\dim(B)$. Unfortunately $2+2=2\cdot2$, so it's easier to get confused in this particular case.
Dec
2
comment How can a black hole zap a galaxy into existence?
This answer is just fine. Black holes are certainly not necessary for star formation (look at all the globular clusters and dwarf galaxies in the universe).
Dec
1
comment Is there a relation between music chords and visible light palette
I might be inclined to argue that pitch is many-dimensional. Color is a three-dimensional space because we have 3 types of cones in our eyes that respond (sort of) independently. But the cochlea frequency-analyzes sound into about as many components as there are bundles of stereocilia. The space of pure sinusoidal tones is 1D, but the space of "sounds" is very much richer.
Dec
1
comment How does a bowl of hot water move by itself?
Or your table is slanted...
Dec
1
comment Does information paradox in the Many Worlds interpretation cause a problem?
Asking for physical analysis of time travel, which is fundamentally at odds with one of the most core principles of physics (causality), is like asking for a mathematical analysis of positive real numbers less than 0. Surely as a philosopher you should appreciate that starting with inherently self-contradictory scenarios cannot lead to any fruitful analysis.
Nov
30
comment Is $F = G\dfrac{{m_1}{m_2}}{r^2}$ really true?
@innisfree You've clearly done more thorough research than me :) Feel free to put everything into an answer so you can get some upvotes.
Nov
30
comment Is $F = G\dfrac{{m_1}{m_2}}{r^2}$ really true?
Cherry picking can be subconscious too. I only used the term because it's clearly what Keyser implied between the lines. In that paper they have a plot where they show the fit to data used by Fischbach, but they restore the Eötvös-Pekár-Fekete data discarded by Fischbach, showing there is no actual trend if the full dataset is used.
Nov
30
comment Possible solutions to the crown problem of Archimedes
Without doing your assignment for you, I'm going to introduce you to two excellent resources far better than raw Google: Google Scholar, and the references section at the end of every Wikipedia article (to be used in conjunction with the inline citations in the article).
Nov
30
comment Would there be forces acting on a body as it traverses space near a wormhole?
Well if there's a typical black hole at both ends you'll have a hard time getting out, won't you? In any event, I can imagine, at least mathematically, a geometrically flat spacetime (no gravity at all) that is topologically multiply connected (essentially, having wormholes).
Nov
30
comment In the Pound-Rebka experiment, does light lose energy?
I'm not too sure what the question is. Are you asking if the idea of continuously changing frequencies due to a continuously varying gravitational field, as hinted at in the first paragraph, should be discarded given the second paragraph? Or am I completely off the mark?
Nov
30
comment Why is a thought experiment a valid way to prove anything?
No. Many consequences of relativity follow from thought experiments. But the axioms do not. Things like time dilation logically, necessarily follow from the axioms of relativity, as illustrated by thought experiments, so if you believe in the axioms you must believe in all their consequences. Because all the consequences we've enumerated have been verified many times over in experiment, we generally believe the axioms, but we aren't logically required to believe in them.
Nov
30
comment Why is a thought experiment a valid way to prove anything?
No, you're missing the whole point. The thought experiment is never supposed to deliver absolute truth. It provides a way of going from (possibly flawed) theory $T$ to observable consequence $R$. Problems with $R$ imply problems with $T$ (think logical contrapositive), and that's the whole point. The experiment provides a way to test the validity of $T$ by producing a testable $R$.
Nov
30
comment Why is a thought experiment a valid way to prove anything?
The thought experiment doesn't prove $R$ in some sense of absolute truth, it only proves that $R$ follows from $S$ and $T$. You are always free to doubt that $R$ holds in the real world, but you have to simultaneously doubt that $T$ and/or $S$ accurately describe the world.
Nov
28
comment Calculating the age of the Universe at temperature 1 MeV
Dear close voters: This is not a duplicate. The issue is the implicit limit of integration, which is nowhere mentioned in the referenced question -- it, like most sources, never draws attention to the fact that we are tacitly defining $t = 0$ to be when $a = 0$.
Nov
28
comment Maxwell's Inspiration to think about fields
Note there is a new History of Science and Math site that this sort of question would probably do well on.
Nov
28
comment Cosmic Calendar
I'm going to hazard a guess that this is one of those "If the history of the universe were compressed to a year" assignments or something. If that's true, then I fear you've missed the point of the assignment. In any event, there is not enough information to answer, since "cosmic time" is not a term outside this assignment. Moreover, this probably runs afoul of our homework policy.
Nov
28
comment Home experiment with airfoils and Reynold's number
"turbulence builds up and increases as time goes on" -- but how fast does it build up, and at what point does it saturate? If you're picturing airplanes losing efficiency or shaking apart because they've been flying at a constant speed for too long, you might want to revisit the relevant timescales in the problem. This will also help guide your experiment, since if the things you want to measure only happen on, say, millisecond timescales, you'll need to measure the system at a high sampling rate.
Nov
28
comment Are atoms made of protons, electrons and neutrinos?
Something to ponder: nuclei with too many protons are unstable to positron emission, wherein a proton "turns into" a neutron, a positron, and a neutrino. Do you see where this might lead to an infinite recursion of infinitely many particles if things really consisted of their decay products?
Nov
27
comment SciFi Stasis Field and the Quantum Zeno Effect
The rate at which you need to measure a system can be enormous: physics.stackexchange.com/questions/33232/… Now someone needs to extrapolate to a macroscopic system and apply a little bit of quantum information theory.
Nov
27
comment Temperature coefficient of resistivity (resistance) in function of temperature
Hi Mike Johnson, and welcome to Physics Stackexchange! In case you're not familiar with latex-style formatting, a basic intro can be found here. Far more thorough coverage is given here.