21,419 reputation
44785
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location Princeton, NJ
age 25
visits member for 2 years, 4 months
seen 26 mins 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.


2h
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."
14h
comment Andromeda/Milky Way collision: How, and how accurately, can a galaxy's lateral velocity be measured?
I don't think there's anything wrong with making this the accepted answer. Just think of some curious person who stumbles on this question after wondering the same thing, skims the top answer, and goes away thinking all we have is indirect evidence, when the truth is that we really can make these sorts of measurements.
22h
comment How does low entropy in the distant past translate into the observed entropy increases?
@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.
1d
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).
1d
answered On which basis we think there is something more than just super dense matter in black holes?
1d
answered Is there a binary black hole system in the middle of the galaxy?
1d
awarded  Nice Answer
1d
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.
1d
reviewed Leave Open Fluid dynamics - immiscible liquids
1d
reviewed Close What are the hypothetic cases when entropy of a closed system may decrease?
1d
reviewed Close Why need for 96kHz, 192kHz audio?
1d
reviewed Close Calculate the attenuation constant on a lossy transmission line
1d
answered Why are Black Holes always referred to as 'Holes"
2d
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.
2d
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.
2d
reviewed Reviewed Why aren't purely Dirac neutrinos ruled out?
2d
reviewed Leave Closed $E=mc^2$ is incomplete?
2d
reviewed Reopen Forces and acceleration on rotating objects?
2d
reviewed Leave Open Electromagnetic field or direct interactions between charged particles?
2d
reviewed Close $E=mc^2$ what is unique about the speed of light?