mimefan599 Posted March 25, 2006 Posted March 25, 2006 If a luminous source that is a digital system, meaning it can be on or off, say a lightbulb, is turned on, but at the exact same moment is launched away from your vision at the speed of light, what would one see. I belive that observer would not see anything. The light would not have had enough time to travel to his/her retina (is it retina? im no optometrist) because the source of the light is being shot away from that persons vision as quickly as the light can travel, therefore the light emited from the lightbulb would not travel away, because those opposite rays would double the speed of light. What do you think?
THoR Posted March 25, 2006 Posted March 25, 2006 If a luminous source that is a digital system, meaning it can be on or off, say a lightbulb, is turned on, but at the exact same moment is launched away from your vision at the speed of light, what would one see. I belive that observer would not see anything. The light would not have had enough time to travel to his/her retina (is it retina? im no optometrist) because the source of the light is being shot away from that persons vision as quickly as the light can travel, therefore the light emited from the lightbulb would not travel away, because those opposite rays would double the speed of light. What do you think? Wouldn't it 'Red Shift' into radio wavelength?
THoR Posted March 25, 2006 Posted March 25, 2006 Depends on the length of the eletrical cord Nah - better to use a candle. In space, the wind wouldn't blow it out.
5614 Posted March 25, 2006 Posted March 25, 2006 Firstly it couldn't travel away from you at the speed of light. As the candle or light source has mass it cannot travel at the speed of light. However if it had a velocity near the speed of light then you would see the light red shift... well, you wouldn't actually see it red shifting, but you know what I mean, I hope!
Dark Photon Posted March 25, 2006 Posted March 25, 2006 Nah - better to use a candle. In space, the wind wouldn't blow it out. in space the candle woudnt burn at all, so a light bulb is more efficient the light woudnt suffer great doppler effect to the lower end of the specrum, however you would still see it as the photons are still emmited. however if the photon was attached to the bulb by some variation of string, under normal circumstances which would pull the bulb, then the bulbs action would be counterd. but since upon emmition the photons are independant of the bulb, thier actions cannot cancel out as they are not acting on the same entity/medium.
Daecon Posted March 26, 2006 Posted March 26, 2006 I would imagine that the individual photons would be red-shifted to infinity. Or as close to infinity as a single quantumn of energy can get. Which wouldn't actually be infinite but imagine a photon with an amplitude or frequency of zero. Or something. Imagine a spaceship observing the light being emitted by a pulsar, then think about what it would look like if the space between the ship and the pulsar started to expand at the speed of light. Would that be a better analogy?
Sisyphus Posted March 26, 2006 Posted March 26, 2006 It would be redshifted to infinity. Of course, that's impossible, but so is a light source travelling at the speed of light, so paradox avoided.
Daecon Posted March 26, 2006 Posted March 26, 2006 But what if space itself was expanding at exactly the rate of c?
Saryctos Posted March 27, 2006 Posted March 27, 2006 yes, you would see the light from your source. It would just be delayed as the light SOURCE is moving, not the light itself. I'm not exaclty sure what all this redshift talk is about... As for the scenario with space expanding; I believe that in this case you would not see the light since it never overcomes the speed of expansion.
5614 Posted March 27, 2006 Posted March 27, 2006 What do you mean "what if space itself was expanding at exactly the rate of c?"? When would space expand at c? Also the thing with c is that it is the same for all inertial observers, that is, you will see the light coming towards you at c not matter what.
wormholeman Posted April 11, 2006 Posted April 11, 2006 If a luminous source that is a digital system, meaning it can be on or off, say a lightbulb, is turned on, but at the exact same moment is launched away from your vision at the speed of light, what would one see. I belive that observer would not see anything. The light would not have had enough time to travel to his/her retina (is it retina? im no optometrist) because the source of the light is being shot away from that persons vision as quickly as the light can travel, therefore the light emited from the lightbulb would not travel away, because those opposite rays would double the speed of light. What do you think? If that was possible, I believe your right.
mr d Posted April 11, 2006 Posted April 11, 2006 hello as the bulb is already emitting light at the speed of light, depending on size of source you would seeing a rapidly shrinking dot of light that would begin red shifting, doppler effect, rather quickly. why, light being emitted by your source would be in all directions, if the ray of light is moving away from the sources direction it would not be trapped by the momentum of the object , but continue to travel in the direction of emission. mr d
5614 Posted April 11, 2006 Posted April 11, 2006 If that was possible, I believe your right.It is incorrect because the speed of light is the same for all inertial observers. The light will come towards you at c no matter what speed the light source is moving away or towards you.
wormholeman Posted April 11, 2006 Posted April 11, 2006 It is incorrect because the speed of light is the same for all inertial observers. The light will come towards you at c no matter what speed the light source is moving away or towards you. Ohhhh cool! Ya I see what your saying.
mimefan599 Posted April 16, 2006 Author Posted April 16, 2006 but since upon emmition the photons are independant of the bulb, thier actions cannot cancel out as they are not acting on the same entity/medium. You don't get it, im saying exactly at the point in time whne the light bulb is turned on, with no passage of time in between these two events, is the bulb flung away. THe photons wouldn't have time to be independant because the exact moment that the photons are emmited the light source is travelling at the speed of the photons, i.e. light.
mimefan599 Posted April 16, 2006 Author Posted April 16, 2006 I suppose i was looking at light in a more particle fashion than a wave fashion or a quanta packet fashion.
5614 Posted April 16, 2006 Posted April 16, 2006 You don't get it, im saying exactly at the point in time whne the light bulb is turned on, with no passage of time in between these two events, is the bulb flung away. THe photons wouldn't have time to be independant because the exact moment that the photons are emmited the light source is travelling at the speed of the photons, i.e. light.Thinking of particles instead of a wave is no problem. It makes this question almost easier to think of and it works. Basically the problems with your situation is this: c = speed of light > The light bulb cannot move at c So for the rest of the question we assume it moves at 99.99999% of c > The bulb would still see the light moving away from it at c, ie. if you were the bulb and you were traveling at 99.9% of c and you emitted some light then that light would run away from you at c relative to you. Note that the photon does not violate the laws of physics, ie. nothing can move faster than c. From your view: The photon is travelling at c, nothing wrong. From someone standing stil watching you and the light: All sorts of relativistic effects start playing here such as length contraction and time dilation which all, you might say illogically, sum up to show that the light does not move faster than c.
wormholeman Posted April 16, 2006 Posted April 16, 2006 It is incorrect because the speed of light is the same for all inertial observers. The light will come towards you at c no matter what speed the light source is moving away or towards you. hmm, heres a thought. To think in this manner, obviosly when the light bulb is facing you the light from it would have to allways be reaching you, because in order for the light bulb to be put in front of you it has to stop, which makes the light allways hit your face. But, if the light bulb is facing you and suddenly it went at 186,000 mph away from you then the light would move away at 186,000 mph. I think that makes sence.
wormholeman Posted April 16, 2006 Posted April 16, 2006 I think this is a hypothetical question, regarding the lightbulb moving at c.
Apeofman Posted May 1, 2006 Posted May 1, 2006 I think this is a hypothetical question' date=' regardingthe lightbulb moving at c.[/quote'] I think your light bulb would gain so much mass that it's light would be trapped by it's gravitational field.
5614 Posted May 1, 2006 Posted May 1, 2006 hmm, heres a thought. To think in this manner, obviosly when the light bulb is facing you the light from it would have to allways be reaching you, because in order for the light bulb to be put in front of you it has to stop, which makes the light allways hit your face. But, if the light bulb is facing you and suddenly it went at 186,000 mph away from you then the light would move away at 186,000 mph.I don't know quite what you are trying to say but no matter what speed the light bulb is moving away or towards you the light will always come towards you at c. This is all a fundemental part of Special Relativity.
YT2095 Posted May 1, 2006 Posted May 1, 2006 I think your light bulb would gain so much mass that it's light would be trapped by it's gravitational field. [/indent'] leaving a perfectly Black "dot" where the light was, and then a Ripple effect around the images presented to the eye like a stone in a puddle of water, leaving all back as normal again but with a high electro-static charge.
Apeofman Posted May 1, 2006 Posted May 1, 2006 I don't know quite what you are trying to say but no matter what speed the light bulb is moving away or towards you the light will always come towards you at c. This is all a fundemental part of Special Relativity. Sorry my mistake, my thoughts were based on effects of The General Theory of Relativity. If i had been more attentive to redading the thread leading to worhole's question it would have been apparant that wormhole wanted an answer based on Special Relativity. In the Special Theory of Relativity, the velocity of the light itself is uninfluenced by the velocity or any other physical property of it's source. Any change of velocity between an observer and light source alters the wave length and hence frequency of the light with respect to that observer, not the observed/measured velocity.
Rocket Man Posted June 14, 2006 Posted June 14, 2006 i'm confused, how does doppler shifting work if light continues at c regardless of the velocity of the thing emitting it?
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