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  • Posted by unitedlc 4 years, 10 months ago
    I always thought the fastest thing in the universe was thought. You know, you think about something so quickly. Then I thought, no, its a blink. Your eye just blinks, and its done. But then I thought, no it's electricity. You flip the switch and all the lights come on instantly.

    But alas, I came to the conclusion the fastest thing in the universe is diarrhea. The other night I was lying in bed. I felt something in my stomach. Before I could think, blink, or flip on the light, I shit all over myself.

    Diarrhea is the fastest thing.
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  • Posted by $ blarman 4 years, 10 months ago
    That's pretty fascinating. Does lead one to wonder, however, if the speed of light is not necessarily a constant what derived conclusions may be in jeopardy...
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    • Posted by 4 years, 10 months ago
      Interesting observation, Blarman! When the speed of light can be slowed down from 670,616,629 mph to zero, what else in physics can be changed so drastically?
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      • Posted by Riftsrunner 4 years, 10 months ago
        The light isn't really slowed down, it is just being bounced around between the atoms. A photon of light takes as much as 1 million years to travel from the core of our sun to its surface due to the bouncing around it encounters on it way out. However, once it reached the surface it speeds off in a straight line that only take 8 minutes to reach the Earth's orbit. So they are exciting the sodium vapor and then sort of locking it into a matrix where photons enter the the vapor and keep getting bounced around until they eventually find their way to the other side. If they were actually slowing it down, it would continue at this arrested speed once it emerged from the other side, but it 'resumes' it's natural mean path and shoots off at speed.
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        • Posted by Steven-Wells 4 years, 10 months ago
          I am in complete agreement with you, R—just adding some more physics.

          The speed of light in vacuum, c, is constant and the top speed limit. Light in a physical medium slows down in proportion to the material’s refractive index n (its optical “density”), which is why it gets bent as it passes through. Light entering a pane of glass at an angle gets bent toward the normal on entering the glass by effectively slowing it down as it bounces around (still at speed c) from atom to atom within the glass with a refractive index n=1.46.
          (Definition: the normal is the perpendicular to the surface. It’s from where we measure angles of incidence, reflection, and refraction.)
          On exiting the other side of the glass pane, it bends back away from the normal to be parallel to its path into the glass, and it continues at speed c with nothing impeding it. Or close to c. Vacuum has a refractive index n=1, air has n=1.0003.
          Water (n=1.33) has a lower refractive index than glass, so the light isn’t bent as much at the surface or slowed as much by bouncing around between water molecules. Diamond is extremely dense optically, n=2.4

          If you ever looked inside a water-cooled nuclear reactor (I have done so) you’d see a blue-green glow called Cherenkov radiation. It comes from nuclear particles that are traveling faster within the water than light travels (in its effective bouncing speed). It is the optical equivalent of a sonic boom, from an object traveling faster than light (or sound) than the speed of light (or sound) in the dense medium. Again, outside of a dense material (air, water, glass, diamond), light goes at speed c, faster than any material object can travel.
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