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Apr
14
comment Capture the entire light field of a 3D scene and construct a virtual scene
Unless you also have a good light source darpa.mil/program/…
Mar
24
comment When thermal IR gets reflected from an object, does it change its wavelength (frequency)
Or if the particle it scatters off has high enough energy the reflected photon is blue shifted! Although philosophically - is it the same photon ?
Mar
19
comment A twin-like paradox, with no acceleration and no 3rd reference point. What would happen?
If they both have the same path, their clocks agree, no paradox. If you argue that either could consider that they were stationary and only the other moved then the fact that they felt acceleration prohibits this
Mar
19
comment A twin-like paradox, with no acceleration and no 3rd reference point. What would happen?
you can't change direction to meet again without acceeration
Mar
7
comment Would this be a practical way to convert tidal energy into electrical energy?
It's called a tidal barrage and is the most common tidal power. But it requires a convenient inlet/estuary with a large tidal range, it can get blocked with silt and causes environmental damage with changes in saanity
Mar
4
comment Would this be a practical way to convert tidal energy into electrical energy?
I was thinking primarily of a wave power device which only had to move the typical waveheight and not the potentially larger tidal range. Although the cost is going to be high if your platform has to accommodate a 10m tidal range
Mar
4
comment Would this be a practical way to convert tidal energy into electrical energy?
Take a look at the inks in the wave power wiki article
Feb
16
comment Charged particle/cosmic ray track on sunglasses
No, you scratched them but only noticed when you placed them at a certain angle to the light
Feb
15
comment Speed of satellite when it falls freely on the surface of the earth
The speed of the satelite gives you the height of the orbit.Then it is simply potential energy. Simple if you can assume gravity is constant, a bit more calculus if you need to consider the change in gravity with height.
Feb
7
comment Seasons of Earths Orbit
Distance from the sun doesn't cause seasons. see physics.stackexchange.com/questions/26785/…
Jan
27
comment Safety of Polonium Isotope source
Or in a form which it couldn't be absorbed, such as plated on an insoluable stainless steel disk. If it stays on the disk you can swallow it and have it come out the other end!
Jan
27
comment How is sun's atmosphere (corona) hotter than the surface itself?
@barrycarter that doesn't explain how heat flows from 6000k surface to several million K corona
Jan
21
comment Why are four-legged chairs so common?
@Yakk only in a platonic ideal. Any microscopic difference in length or flatness means it will rock. That's why tripods have 3 legs
Jan
20
comment Why are four-legged chairs so common?
Only a 3 legged chair can be placed exactly on a flat surface. A 4 legged chair can only ever sit perfectly on an curved surface - and even then only in a single orientation
Jan
6
comment Is an x-ray maser possible?
@ChrisWhite - the dupe is a bit technical.
Dec
29
comment Do magnetic fields exist beyond the gravity of a black hole?
No - the fields are outside the blackhole, just closer than have been observed previously
Dec
8
comment Question about Gravitational Deflection of Light
Yes - it's even possible for light to orbit a blackhole and for you to see the back of your own head
Nov
26
comment How the speed of light is constant in the universe if it decreases in water and glass and some other objects?
When I explain SR I like to say that ε₀μ₀ are constant and that 'c' follows from them. Because "speed of light" is confused with being able to see the effect in most SR explanations
Nov
26
comment How the speed of light is constant in the universe if it decreases in water and glass and some other objects?
Even without the defn of the second, isn't it more normal to think of time changing in a gravitational field rather than permeability/permittivity changing ?
Nov
24
comment Is there any aspect of an explosion resulting from a nuclear weapon test that cannot be simulated using super computers?
@KyleKanos - yes but some pedant was going to come along and claim that there are effects which can't be modeled because of QM