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Fowler
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If a photon travels at the speed of light it will appear as if it's time has stopped. But if it's time has stopped how can it move?
Fowler said:If a photon travels at the speed of light it will appear as if it's time has stopped. But if it's time has stopped how can it move?
pervect said:The underlying idea being disucssed is the idea that "time stops". But what does this mean? I believe that the usual (and incorrect) picture of "time stopping" that motivates the OP's question is the notion that clocks slow down and eventually stop when compared to the imagined notion of "universal time", a notion of a sort of time that everyone agrees on and that pervades the universe. But the real issue is that there is no such universal time that pervades the universe. Sinceit doesn't (and can't exist in the context of Special relativity, being incosistent with the theory) , it's impossible to compare clocks against it!
It's speed is defined by a clock at rest, which isn't slowed down.Fowler said:But if it's time has stopped how can it move?
bcrowell said:Not reasoning correctly about Lorentz transformations.
DaleSpam said:In relativity the fact that the spacetime interval between two events is 0 does not imply that the two events are the same. This is a difference between Minkowski geometry and Euclidean geometry.
Your original question asked how can light move if time is stopped for it. Obviously, coordinate time is not stopped in our reference frame and our proper time is not stopped either, so you are clearly asking about something else. There is no reference frame for light, so you cannot be asking about the coordinate time of the light. So that leaves the proper time of the light. Proper time is equal to the spacetime interval along a timelike path. Light travels along a lightlike path, so the spacetime interval along a light path should not be called proper time, but nevertheless the interval itself is well defined and is 0 along the path of light.Fowler said:So this seems that this has been the least disagreed on answer, and if I'm understanding it correctly you mean:
Just because something is not moving along the spacetime axis it does not mean it cannot move though the first 3 dimensions.
In Euclidean geometry, the locus of points which are a fixed distance from the origin is a sphere. Different distances correspond to spheres with different radii. The locus of points which are 0 distance from the origin is a degenerate "sphere" which is the single point located at the origin.Fowler said:But then how come light isn't just everywhere always then?
Jorgelff said:How a photon "see" the world around it?
Fowler said:If a photon travels at the speed of light it will appear as if it's time has stopped. But if it's time has stopped how can it move?
Jorgelff said:How a photon "see" the world around it?
The concept of time is based on the movement of objects through space. However, light does not experience time in the same way that objects with mass do. According to Einstein's theory of relativity, the speed of light remains constant regardless of the observer's frame of reference. This means that for light, time does not pass at all.
No, the speed of light is limited to approximately 299,792,458 meters per second in a vacuum. While it appears that light does not experience time, it still must travel through space at a fixed speed. This is known as the speed of causality, and it is a fundamental principle of the universe.
Light travels through space as electromagnetic waves. These waves do not require a medium to travel through, unlike sound waves which require a medium such as air. The properties of these waves, such as wavelength and frequency, determine the color and energy of the light.
Yes, according to Einstein's theory of general relativity, gravity can bend the path of light. This is known as gravitational lensing, and it has been observed in space by the bending of light around massive objects such as galaxies and black holes.
While light does not experience time, it still takes time for light to travel through space. However, the distances between stars and galaxies are so vast that the time it takes for light to reach us is negligible in comparison. For example, it takes light from the sun about 8 minutes to reach Earth, but it takes light from the nearest star, Proxima Centauri, about 4.2 years to reach us.