Recent content by mun

No one deliberately PICKED a scenario to ensure no one in this forum won't have an answer for. That's the scenario I came up with because that's what I have in hand from an old Christmas shower light. Whether it could be reduced to a simple toy example using 1D gratings is a separate issue. This...

I'm asking because I don't have the equipment or gratings. And in the current climate, parts can be hard to come by. Also I'm asking purely out of curiosity and thought this would have been experimented many times and an established answer exists. For experimenters that have the resources...

Indeed, it's not a typical diffraction grating. This isn't the type with N lines per mm, but rather I believe this is based on FFTs. Still, these are diffraction gratings. The grating pattern looks something like this: My question is mainly will each beam detracted by the first grating be...

Hi I have a basic question about the effect of transmitting a laser beam through multiple diffraction gratings. Suppose a diffraction grating was used to produce many spots as follows: Would adding a second grating of the same pattern result in more spots/maximas? If so, would the resulting...

Actually, some speak about the rotational velocity of stars: http://astro.berkeley.edu/~mwhite/darkmatter/rotcurve.html "To make a rotation curve one calculates the rotational velocity of e.g. stars along the length of a galaxy by measuring their Doppler shifts..." I thought a rotation...

Hi Thanks for the reply. So how is the rotational velocity of a galaxy related to the orbital speed of the constituent stars? It's probably not as simple as being related by a factor of a constant. What are the dependent factors here? Thanks

Hi Is "orbital velocity" supposed to be the same as "rotational velocity"? it seems that a "rotation curve" is supposed to plot the rotational velocity of a star, but then some articles e.g. http://en.wikipedia.org/wiki/Galaxy_rotation_problem claim "orbital speed" is plotted. The equation...

Hi Is "orbital velocity" supposed to be the same as "rotational velocity"? it seems that a "rotation curve" is supposed to plot the rotational velocity of a star, but then some articles e.g. http://en.wikipedia.org/wiki/Galaxy_rotation_problem claim "orbital speed" is plotted. The equation...

Hi, If one were to formalise physics, what would be the appropriate logic to use? Is FOL already sufficient, since the mathematics involved are first-order, e.g., sets, differentials. Or, is a more expressive logic needed?