Speed of Light
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- johndiggity0
here's the answer:
http://www.madsci.org/posts/arch…
- vsc0
hi, sorry to intrude. i think the light source would be visible but there would be no lighting effect or beam.
- Soler0
interesting johndiggity,
although that experiment is assuming that the flashlight is moving at HALF the speed of light, not the speed of light.
- johndiggity0
the flashlight will never reach the speed of light because it has mass. it can only come infinitely close to reaching it. that's the point.
- ********0
johndiggity is right
- tparsons0
right
- johndiggity0
ok, everyone can go about their business now.
- lnu0
I'm glad we got that sorted out.
- Soler0
whew
- mrsparkle0
You could see the light from the flashlight and here's why:
This is explained by playing with the equation E=mc2.
As the speed of the flashlight aproaches the speed of light, the mass of the flashlight becomes greater until it's mass of the flashlight becomes infinite and therefore an infinite amount of energy would be needed to propel the flashlight with infinite mass at such a speed.
Therefore the flashlight can't travel at the speed of light.
Therefore you would be able to see the light no matter what direction it's pointing or when you turned it on.
Sorry if this wrecks any Star Trek fantasies that you've been having.
- mrsparkle0
i wish it didn't take me that long to type that.
nice work JD
- lnu0
I'm sorry but wouldn't the close to infinite mass of the flashlight suck up the light like a black hole?
- mrsparkle0
no, because the mass would never actually become infinite, just get close.
But good theory though.
- airey0
what if someone snuck in and stole the flashlight before the experiment began?
- ********0
Speed of Light
Question:
A flashlight is travelling at the speed of light, in a vacuum. It's turned on.Is the light visible?
Soler
(Jun 14 05, 15:08)
------------------------no, this is where relativity is challenged
- bk_shankz0
When it comes to comparing distances, as well as times, measured in frames moving at high speeds with respect to one another, things get more complicated. Lorentz transforms and a new form of Pythagoras theorem involving time needs to be developed, and phenomena like length contraction and frame-dependent simultaneity need to be understood. Although we don't have time to treat these here, one of the complications is that relative velocities can no longer be calculated by simple addition. In fact, only in this way is it possible for light in a vacuum to travel at the speed of light relative to all observers, even if the observers are traveling at high speeds with respect to each other.
There is a simple way to keep track of these effects. Note from above that proper-velocity w can be written in terms of coordinate velocity as w = ?v = v/Sqrt[1-(v/c)2]. If one object is moving rightward with coordinate speed v1 in the frame in which you measure distances, and a second object is moving leftward toward the first with speed v2 in that same frame, then the proper-velocity of the first object in the frame of the second is w12 = ?1?2(v1+v2). In other words, when calculating relative proper velocities, the coordinate velocities add while the gamma values have to be multiplied. This expression then allows one to calculate the relative speeds and energies attainable when throwing objects (like elementary particles) at each other at relativistic speeds from opposite directions.
What is the relative proper-velocity, in lightyears per traveler year, of two 70 GeV electrons in head-on collision trajectories? This may be the "relative-speed record" for objects accelerated by man.
My old stomping grounds.
- ********0
actually the answer is unknown, it alludes to time travel crap theory
- bk_shankz0
I don't think the example is that far odd from reality. In a particle accelerator particles approach the spped of light and emit a photon which travels at the speed of light. Im pretty sure the light is visible.
- spifflink0
according to relativity, you actually can't push something like that up to the speed of light. as the object approaches the speed of light, it converts mass into energy, until it reached almost infinite mass, making this whole thing pretty much impossible by any foreseeable means.
- NegativeSpace0
pwnd