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Bruninho
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If I shine a torch at the moon the light will after a time be seen on the surface. If I then swing the torch so as to move across the moon does the spot of light on the surface travel faster than c?
Yes, the spot can move faster than c. But as the spot moves from one side of the moon to the other, no information travels between those two points. (Astronauts on opposite sides of the moon cannot use the spot to communicate; the only potential for information transfer is between the light source and the moon, and that information would of course travel at speed c.)gonzo said:I was thinking a bit more about this, and can even the spot move faster than C? Wouldn't that imply that information can travel faster than C?
The travel time only introduces a delay in the time it takes the "spot" to reach the object; but that delay is a constant 10 years, so it doesn't affect the "sweep rate" of the spot.Think about a more extreme example. You shine a light 10 light years away in one direction, then flip around to shine on an object 10 light years away in the opposite direction. By the original example the "spot" has moved 20 lightyears in a very short time, but this neglects the travel time for the photons from the flashlight to the object.
gonzo said:I was thinking a bit more about this, and can even the spot move faster than C? Wouldn't that imply that information can travel faster than C?
"Shining a Torch at the Moon: Does Light Travel Faster than c?" is a thought experiment that explores the concept of the speed of light and whether it can be exceeded by other sources of light, such as a torch.
The speed of light (c) is a physical constant that represents the speed at which light travels in a vacuum. It is approximately 299,792,458 meters per second.
No, according to the laws of physics, nothing can travel faster than the speed of light. This is known as the universal speed limit and has been confirmed by numerous experiments and observations.
If light could travel faster than the speed of light (c), it would violate the laws of causality and create paradoxes in our understanding of time and space. Additionally, it would require an infinite amount of energy to accelerate an object to speeds faster than c.
While the thought experiment may seem far-fetched, it helps us to better understand the concept of the speed of light and its implications on our understanding of the universe. It also highlights the importance of scientific inquiry and experimentation in uncovering the mysteries of our world.