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location Princeton, NJ
age 26
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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.


May
23
comment Are there reasons for the discrepancies in absolute temp units - Kelvin vs. kelvins vs. degrees Kelvin?
You've cited three standards already - do you want us to cite more standards? Or do you just want input from actual working scientists on what is acceptable?
May
23
comment Is it possible that black holes are also neutron stars, but so dark that we cannot see them?
@auxsvr The latter. Under the former definition, nothing is infinite, and in fact supermassive black holes have surprisingly low densities.
May
22
comment Is it possible that black holes are also neutron stars, but so dark that we cannot see them?
@Peter In a very real sense, what happens on the inside of a black hole is not subject to scientific inquiry, at least as far as classical general relativity is concerned. No measurement you can make, not even in theory, can distinguish between different hypotheses. All that matters is the total mass of the black hole. GR cares no more about the density of matter in a BH than it cares about how many angels are dancing inside the event horizon.
May
22
comment Momentum of Light Question
$(60\ \mathrm{J})/(3\times10^8\ \mathrm{m/s}) = 2\times10^{-7}\ \mathrm{m/s}$
May
22
comment How does one refute a Machian mechanism for inertial emergence?
(3) In all this, you haven't given the definitions of "Machian" or "principle of equivalence" that you are working with. You admit that there are different definitions of the former, and there are at least three versions of the latter. In fact, the utter disarray of the Wikipedia article is a testament to how no two physicists agree on the wording of the equivalence principle, and why all science is done with the mathematical statement of all metrics being locally diagonalizable.
May
22
comment How does one refute a Machian mechanism for inertial emergence?
This is a really long post and I must say I don't understand half of where you're going with it. Some comments, though: (1) Spacetime is always locally Minkowskian; no one would ever claim otherwise, and the only experiments that could in principle detect curvature are those that take place over extended regions. (2) We don't know the mass of the Sun by pushing on it with a calibrated spring; we know the mass by observing the Earth's orbit (again, over an extended region).
May
21
comment Photobombing without app used by Harley Davidson
I was always under the impression that all consumer cameras had IR filters explicitly for filtering out that light. I guess those filters are not as ubiquitous and/or sharp as I thought.
May
20
comment Why does Minkowski space provide an accurate description of flat spacetime?
Related: physics.stackexchange.com/q/112038
May
20
comment An error in Gravitation by Misner Thorne and Wheeler?
Just two errors? I find that unlikely.
May
20
comment Does cosmic censorship rule out stable toroidal black holes? How?
@AlanSE I just wrote up a somewhat lengthy review of toroidal horizons related to this question: physics.stackexchange.com/questions/92224/…. I don't know if you've already read those papers, but they show many ways you can't have tori, including topological (not cosmic) censorship.
May
19
comment How thick (in molecules) would a piece of paper be if it was folded to the moon?
0.001 cm times $2^{42}$ gets you 11% of the way to the Moon...
May
18
comment How are matrices used to represent quantities, and what is the meaning of a matrix?
I don't see anything wrong with this. To sum up for the OP: if you think of operators as matrices, the "mean" (which every other book I've seen calls "expectation value") is left-multiplication by a tacitly agreed-upon row vector and right-multiplication by the corresponding column vector.
May
17
comment Why isn't it $E \approx 27.642 \times mc^2$?
The answer has nothing to do with unit choices or "naturalness," as everyone seems to think. And in fact the lack of a constant in the formula for time dilation directly leads to the lack of a constant in $E=mc^2$. A good place to start is Einstein's (unfortunately rather terse) 1905 letter. If I find more time later (and if no one else has done it yet), I can write up Einstein's ideas in more modern parlance.
May
16
comment Which experiment gave scientists reason to believe nuclear fission/fusion produced energy?
@TimS. It had been known since 1905.
May
15
comment Different degrees of freedom with RGB, CMYK and Frequency
Related: Is it possible that there is a color our human eye can't see? (though you wouldn't necessarily guess from the title)
May
15
comment Question on the stability of the solar system
It is important to note that chaotic systems can still have bounded orbits; chaos does not preclude stability.
May
15
comment What limitations are there in measuring physical properties accurately?
32-bit IEEE 754 floats have, depending on how you count, 23 or 24 bits in the mantissa, and $2^{24} < 10^8$.
May
14
comment Could airport security possibly distinguish gold and silver coins from other coins?
But aren't airport X-ray machines just looking at Compton-backscattered photons? They aren't doing transmission spectroscopy, but are probably just seeing if anything looks particularly bright in backscattered light. And of course millimeter detectors are entirely different.
May
13
comment Astronomical Constant in Astronomical units?
I'm curious what implementation runs into trouble here. Even single-precision floats should comfortably hold $GM_\odot$, $r^2$, and their quotient in SI units. I only ask because many solar system simulations out there use unstable integration algorithms, and people sometimes blame floating-point precision for the inevitable problems that arise.
May
13
comment How quickly was the Earth rotating 250 million years ago?
I thought the meter was defined based on the length of a meridian, rather than the equator, not that it matters at all here.