imallett
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 Mar 17 comment Why do beams of light (from torches or other directed sources) not extend to infinity? I agree that scattering is probably the main culprit here. But, the geometry of this is such that the infinitely long beam projects to a finite length on your visual field. So yes, it does extend to effective infinity, but as it does so, it appears to move across the sky less and less. Jan 29 comment Can the Earth leave orbit if the population of humans and other live forms increases? Clue: what happens to corpses? Sep 18 accepted Sellmeier Refractive Index of Standard Air Sep 6 comment Alongside a light ray (in another medium) The problem is the OP's confusion about what is meant by "speed" of light. So you should compare this to the group velocity. Sep 1 comment Why can we see through rain? At HPG 2015 (this year) there was a keynote about how they are developing adaptive headlights that try to miss individual raindrops. Earlier work. Aug 15 comment Can a Skydiver Land On a Large Slide and Survive? My favorite example of this principle is falling off a building by riding the elevator down. Apr 19 comment Object moving in a circular path without accelerating Pretty sure it does accelerate when it goes around the curve. Apr 18 comment What are the tidal effects of Io on Jupiter? @DavidHammen The answer on the linked page models the tidal forcing function, which as I literally just said is not what I am reporting here. If you fancy this answer incomplete, there's a wonderful little button labeled "edit" that I encourage you to use. Apr 18 comment What are the tidal effects of Io on Jupiter? @DavidHammen The tides are an extremely complicated function of the tidal forcing function, which itself is a function of the above difference in force. Since the OP was asking for intuition (see also the WorldBuilding Thread), this clarifies the effect. Apr 18 revised What are the tidal effects of Io on Jupiter? Fix time-pressured (I had to give a talk) mistakes. Apr 17 answered What are the tidal effects of Io on Jupiter? Apr 8 comment How can the contact point of rolling body have zero velocity? +1 This is the correct answer. The OP's confusion about "continuous motion" and "zero velocity" being contradictory is due to these concepts applying separately in different reference frames. The remedy is to show the trajectory a continuously moving point takes in the other reference frame. Mar 23 comment Is rocket propellant meaningfully a form of “space junk” Also note only a small fraction of possible orbits are used. Feb 5 comment Why do most formulas in physics have integer and rational exponents? For a real world example of this, many view $2\pi$ as a bletcherous fossil from the past. Jan 29 comment Will we ever be able to view the past? This powerful-machine-that-can-view-light-from-hundreds/thousands-of-years-ago existed in the 17th century. Today's machines can see up to 13.37 billion years ago! Jan 20 comment Don't heavier objects actually fall faster because they exert their own gravity? @JoeBlow (aside) I did calculations a while ago on the magnitude of suchlike. On the equator for a human, the acceleration of the Earth is on the order of $10^{-22}$. Jan 13 accepted Melting and Boiling Points of Odd Materials Jan 6 comment What does 1714 mean in hydraulics? @ChrisWhite question: is light-years/meter dimensionless? I see how it could be, since it's length/length--but, it seems weird to me since you aren't counting the fact that the units--the "dimensions"--you canceled are different. Radians, for example, are dimensionless--but degrees are not--for a similar reason. Dec 25 comment How can we take pictures of something billion of light years away? If Anna can throw a ball and make it stay in the air for 1 minute, then she's probably not a very slow thrower. Dec 24 awarded Yearling