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location Princeton, NJ
age 25
visits member for 2 years, 2 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).


16h
reviewed Reviewed entropy of a long molecule chain with respect to its length
16h
reviewed Close Which moves faster in a time $t$: $A$ or $B$?
1d
answered Really quick question about the order of operations in the Lorentz force
2d
comment How Earth protected from the gamma rays generated by Sun?
@sugunan Space suits are not capable of stopping gamma rays. Nothing can stop gamma rays except by being very thick.
2d
reviewed Close Self-replication of gravitons in string theory
2d
reviewed Reject suggested edit on What causes a Phase-Transition?
2d
comment How Earth protected from the gamma rays generated by Sun?
Minor correction to your logic: Many high-energy photons (in the regime where their interaction with matter is dominated by Compton scattering off electrons) basically only care about the column density along their path. And the full atmosphere has the same column density as 1 meter of lead (or 10 meters of water). That is, we only like dense materials because they make shielding more compact.
2d
comment How Earth protected from the gamma rays generated by Sun?
@HDE226868 actually that page has a good image, since the Sun does produce some gamma rays. Its corona is millions of kelvin, so there is a (small) source other than the core.
2d
comment How Earth protected from the gamma rays generated by Sun?
I think what NASA was trying to say (not too clearly) is that charged cosmic rays (not gamma rays of course) hit the upper atmosphere all the time, and this then produces gamma rays, so you want to point your gamma ray telescope away from Earth to avoid contamination.
Oct
18
comment Verifying radiation measurement smart phone applications
"highpass-filters every individual pixel and all three color channel": just to be sure, you're not filtering each image independently, right? When a cosmic ray, for instance, strikes a CCD, the most common outcome is a hot pixel. The only hot pixels you should remove are those that persist from one image to another. Also, I don't know the details of consumer cameras, but I've heard and fully believe they do similar filtering before saving the data (because no one wants grainy images reminiscent of 1990s-era digital cameras).
Oct
17
comment Upside down images on the surface of the water
Are you unclear as to why there is a reflection, or are you unclear as to why the reflection is upside-down?
Oct
16
comment Why do the big nuts always remain at top? The Brazil-nut Effect
Fun fact: this same effect has been proposed to occur in asteroids, many of which are basically rubble piles. Just looking at the surface might mislead you as to the size of the typical rock in an asteroid.
Oct
15
comment What does the “size of the universe” mean if the Universe is infinite?
@Goodies The observable universe can be made arbitrarily small as you go back closer to the big bang, but see the last few sentences I added. If you scale your coordinates with the expansion of space, there is just as much volume then as now. The "point" you envision is the whole observable universe, not a part of it.
Oct
15
answered What does the “size of the universe” mean if the Universe is infinite?
Oct
14
comment What experiments compete with BICEP 2, and when are their results expected?
There is also Spider.
Oct
14
comment How did Newton establish his famous third law of motion?
Re "We can prove 2nd law using calculus": see physics.stackexchange.com/questions/2644/…
Oct
14
revised What's wrong with my derivation for the spring constant?
tex and grammar
Oct
14
reviewed Edit suggested edit on How to calculate scalar neutron flux
Oct
14
revised How to calculate scalar neutron flux
Adding variables in latex and some minor style corrections
Oct
12
reviewed Close Physics - Waves (Help!)