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location Princeton, NJ
age 24
visits member for 1 year, 8 months
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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).


Mar
14
comment Why is lightning more rare during snow storms than rain storms?
Related: physics.stackexchange.com/questions/4006/…
Mar
13
comment How can a singularity in a black hole rotate if it's just a point?
I have to disagree with this providing an answer to the OP's concerns. While true that the Kerr singularity is a "ring" in some convenient coordinate system, at best this just picks out a direction. If the OP is unwilling to accept angular momentum as intrinsic to spacetime, then a hoop is no better than a point: which way does it rotate? The point vs. ring distinction is a red herring here. Besides, classical mechanics self-consistently has point particles with nonzero angular momentum.
Mar
11
comment What makes some laser beams visible and other laser beams invisible?
I use green for pointing out stars in the sky; violet does indeed appear too dim, and blue lasers are expensive enough that I haven't tried.
Mar
10
comment How does isotropy of free space imply $L(v^2)$ for a free particle?
I don't have the book on me, but does he need to exclude this case? As in, any function of $v^2$ is equally a function of $|\mathbf{v}|$ and vice versa. In other words, are you implying that he really needs to show $L \propto v^2$ (modulo a constant) for some future result?
Mar
9
comment How was this dot identified as a mystery planet originally (Pluto in this case)?
@PeterMortensen Assuming circular, coplanar orbits, then I think measuring just the position of the planet and the rate of change of that angle (i.e. using just two images) gives you enough information to find its distance. But eccentricity adds another parameter, so you need more observations. Of course, most of Pluto's motion on sky is actually due to us moving, so in the limit that it can be taken to be still, you can again approximate its distance with just two measurements.
Mar
8
comment Zeno’s Paradox of the Arrow
That depends on your definition of "in motion." The sensible definition says velocity is nonzero if and only if the object is in motion. Zeno's definition of "in motion" isn't defined for a single instant.
Mar
8
comment Initial conditions of the origin of the universe
Gravity and matter were always there. The only thing that happened at age 300,000 is that matter changed from plasma to gas, thus becoming transparent to light.
Mar
7
comment What is the most stable nuclide of an isobar?
Note that this is precisely the ambiguity that results in both Fe-56 (mass) and Ni-62 (binding energy) as being quoted as the most stable isotopes.
Mar
4
comment What is the theoretical wattage output of a Tokamak fusion reactor?
Here's a deeper question for you to ponder: How does the power generation per unit mass compare for a fusion reactor (or fusion bomb) versus the Sun? I think you might be surprised.
Mar
4
comment Solving actual weight lifted
Related? physics.stackexchange.com/q/52701
Mar
1
comment What will be the relative speed of a photon in a light ray to another photon of opposite direction light ray?
possible duplicate of Double light speed
Feb
28
comment Toroidal Planets
Citations of the 1974 paper include some interesting finds, like this.
Feb
28
comment Best Sets of Physics Lecture Notes and Articles
Repeat after me: THIS IS NOT QUORA
Feb
28
comment Silicon-based life
Brought up long ago on meta: meta.physics.stackexchange.com/questions/2804/…; my own opinion is that this is hypothetical biology, not astrobiology (the latter being about how life as we know it can exist in specific extraterrestrial environments).
Feb
28
comment twin paradox inferring cosmic speed limit
Re: the first sentence: "Einstein considered this to be a natural consequence of special relativity, not a paradox as some suggested." (Wikipedia) That is, special relativity implies the correct interpretation of the "paradox," not the other way around.
Feb
27
comment Can we solve California's drought crisis by pointing parabolic mirrors at the ocean?
Is there any reason this should be more efficient than, say, tried-and-true desalination plants? I'm reasonably certain most of California's utilities (and transportation) shortcomings are the result of human ineptitude more than location.
Feb
26
comment Maximum permissible speed while going down a ramp
@Awesome The positive -> negative fix has been made; apologies John if we inadvertently broke your post.
Feb
26
comment How fast is the Earth-Sun distance changing
Yes! Thank you! I feared no one would ever post an answer. Also, welcome to the site!
Feb
25
comment why does the CMB change so slowly
Note that at $z$ of 1000, 1 light year is a few milliarcseconds across.
Feb
24
comment Sun's Right Ascension appears to be wrong in my Stellarium
This would be great if you could give a sentence or two explaining how the Sun's RA varies over the course of the year.