Let's discuss the speed of light!

• Phunkie wrote on 2010-10-08 21:03
  I thought up of an interesting scenario.
  
  We all know that the speed of light is the upper limit of how fast an object can travel. (Let's ignore tachyons and other theoretical particles which may travel faster than light.)
  
  Imagine an infinitely deep hole on Earth. Fall into it and you'll keep falling forever.
  
  With an acceleration due to gravity of 9.81 m*s^-2, your speed will eventually approach the speed of light. It will take some time of course.
  
  But I stated that nothing can exceed the speed of light. On top of that, any object with mass can never travel at the speed of light, c.
  
  Question is, what happens to a mass that falls infinitely with a certain acceleration?
• Shirayuki wrote on 2010-10-08 21:05
  Wouldn't it disintegrate far before it would reach the speed of light? D;
  
  (considering the hole was on earth)
• Okitaru wrote on 2010-10-08 21:13
  Well, isn't there a cap to objects how far they can go from falling acceleration already, what was it called... I dunno, I didn't study it so I don't remember the muchless complicated name...
  So...
  I'll be leaving...
• Mrlucky77 wrote on 2010-10-08 21:19
  Speed of light = C.
  
  
  PROBLEM SOLVED.
  
  WITH WATERMARKS.
  
  

  [Image: http://www.personalizeaza.ro/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/p/r/problem-solved-tricou-personalizat.jpg]

  
  
  
  Also, it could be possible I guess, with the ASHPD (Portal gun).
  
  
  
  Wait, nevermind.
  
  

  Quote from Chuugoku;179417:

  Well, isn't there a cap to objects how far they can go from falling acceleration already, what was it called... I dunno, I didn't study it so I don't remember the muchless complicated name...
  So...
  I'll be leaving...

  
  
  
  It's called Terminal Velocity.
  
  
  [video=youtube;P_bTsdmjgvs]http://www.youtube.com/watch?v=P_bTsdmjgvs[/video]
• Phunkie wrote on 2010-10-08 21:23
  Assume that there's no fluid through which this mass is falling.
  
  It's vacuum.
• Mrlucky77 wrote on 2010-10-08 21:28
  Hmm, so an object is flying through space... It COULD be possible. You know those food chains that show big fish eating smaller fish which are eating smaller fish etc etc etc?
  
  Well, replace those with ships (SO MANY SHIPS) and make each shoot out eachother, so that each successive ship is faster than the previous.
  
  Refer to Godfellas - Wikipedia, the free encyclopedia where Bender is faster than the Planet Express, because he is shot out of it with high force while the PE ship is going at fulll speed.
• Virtue wrote on 2010-10-08 21:30

  Quote from Phunkie;179431:

  Assume that there's no fluid through which this mass is falling.
  
  It's vacuum.

  As far as I know there's no perfect vacuum so the object will still reach its terminal velocity and then stop gaining speed.
• Phunkie wrote on 2010-10-08 21:32

  Quote from Virtue;179438:

  As far as I know there's no perfect vacuum so the object will still reach its terminal velocity and then stop gaining speed.

  
  
  Assume a perfect vaccuum, just like the speed of light is 3x10^8 m/s in empty space.
  
  What happens to the mass of the object? That's what I wanna know.
• spazzyorbit wrote on 2010-10-08 21:49
  Quantum physics dont allow perfect vacuums to exist.
• Virtue wrote on 2010-10-08 21:54

  Quote from Phunkie;179442:

  Assume a perfect vaccuum, just like the speed of light is 3x10^8 m/s in empty space.
  
  What happens to the mass of the object? That's what I wanna know.

  Then the object will go 0,9c, then 0,99c, then 0,999c... and as we all know, 0.9... = 1, so eventually it must go the speed of light, as there is no difference between point-nine repeating and one. But it never goes past it. And the mass'll become infinite and it becomes a black hole that swallows earth.
  
  Aside from that, to fall infinitely towards something, you have to be an infinite distance away, if you consider the formula F=(G*m(1)*m(2))/r², you'd realize that if you have an infinite distance, the force would equal zero, so what you're suggesting is impossible. So an infinitely deep hole on earth is impossible.
• Justified wrote on 2010-10-08 21:57
  If the hole/space was infinitely deep, then the distance between the falling body and the object causing gravity would be infinitely long. Thus, the gravitational force would be infinitely small, and there would be little to no acceleration.
  
  The need for a vacuum takes a back seat to that.
  
  Edit : FFFFUUUUUUU Ninja'd.
• Phunkie wrote on 2010-10-08 22:01

  Quote from Virtue;179457:

  Then the object will go 0,9c, then 0,99c, then 0,999c... and as we all know, 0.9... = 1, so eventually it must go the speed of light, as there is no difference between point-nine repeating and one. But it never goes past it. And the mass'll become infinite and it becomes a black hole that swallows earth.
  
  Aside from that, to fall infinitely towards something, you have to be an infinite distance away, if you consider the formula F=(G*m(1)*m(2))/r², you'd realize that if you have an infinite distance, the force would equal zero, so what you're suggesting is impossible. So an infinitely deep hole on earth is impossible.

  
  
  Sounds good!
• Okitaru wrote on 2010-10-08 22:09
  Well gee forgetting that makes me feel ridiculous :v
  Can I go emo corner now?
• EndlessDreams wrote on 2010-10-08 23:32
  How is there an infinitely deep hole in the Earth anyways? What does that even mean in real life?
  
  If you fall into one, Pikachu will kill you before you know what happens.
• Zid wrote on 2010-10-09 15:58
  Has to be a perfect vacuum, first of all.
  
  Second, if the hole is infinite, that would mean there is no other object "on the other side" to impose gravity on the "falling" object, thus there would be no force/acceleration on the "falling" object to change its velocity. Unless, somehow, there's a self-contained acceleration system on the said object (like a rocket or something). If said self-contained acceleration system has enough fuel or whatever, then potentially, the object itself might reach the speed of light.