Pingback: Q: According to relativity, things get more massive the faster they move. If something were moving fast enough, would it become a black hole? Spaceman heading to star 10 light years away, as measured by Ground Control on Earth.
Speed attained is close to the that of light. Does the actual distance contract that the spaceman has to travel? So, does the period taken for the Spaceman to reach the 10 light year away star distance divided by speed , now take less time, than had been calculated prior to the journey due to the shorter distance now being experienced as a consequence of length contraction or does time dilation result in the actual journey time equalling the calculation prior to setting off?
Paul Quinn Length contraction and time dilation are two sides of the same coin. The space man would say that the distance was shorter and that his watch ran normally length contraction. I can understand that we observe things and things will look different to different people based on movement and their location. And I love the maths to work out what length an object will appear as. But just because of the order of events may be screw-if and B fore A, to me does not change the facts that the pole is still shorter than the barn.
In fact I noticed you talk about the pole being longer then in your next paragraph after you say its real we jump into being shorter with length contraction. SO to me you used an example to prove the opposite. And why is it real. If I pressed Pause on the universe at that exact moment as the pole vaulter and the rod stayed in place and I walked around it. I do not believe it would be longer than the barn. But was only being observed longer than the barn.
I had this story. If a space ship at light speed travelled 25 light years to earth. It wold take 25 years for the light of that event to arrive and at the ship being 24 lights years out, would take 24 light years to arrive and so on.
So when it gets to earth, assuming you could see it all. The light from all events would arrive all at once. Well truth is the ship is still the same length, but all we are seeing is the effect of light bringing the image to us out of event. Maths can be used to work out length dilation based on an observation, but I think it is being used the wrong way around.
Objects look longer at speed, and we use their speed and reverse engineer the length to work out the actual length of the object. But I could be wrong and everyone contradicts the way I see it, but I am yet to be convinced.
Can you help. The effect you described at the end, with a ship approaching at the speed of light, is a strictly visual effect. Pingback: Q: In relativity, length contracts at high speeds. Is it distance or space or is there even a difference? In the pole vaulter example, I can see why the pole vaulter views the pole as longer than the barn because they are approaching the front of the pole and moving away from the back of the pole.
In the train track example the observer who was stationary relative to the lightning strikes saw them happen at the exact same time not one before the other. Conor The briefly shut barn doors take the place of the lightning strikes, not the ends of the pole passing through the doors.
The farmer sees them simultaneously closed for a moment, with the pole vaulter inside. The pole vaulter sees the door in front of him briefly closed first, then a little later the door behind him closed. Notify me of follow-up comments by email. Notify me of new posts by email.
There's a book! It's a collection of over fifty of my favorite articles, revised and updated. It's interesting. This interval is the quantity of interest, since proper time itself is fixed only up to an arbitrary additive constant, namely the setting of the clock at some event along the world line.
The standard instruments used nowadays to measure a length are — ruler, meter scale, measuring tape, vernier caliper, and screw gauge. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Physics What is the cause of length contraction? Ben Davis July 4, What is the cause of length contraction? Does light undergo length contraction?
How does length change with speed? Why do objects shrink as they approach the speed of light? At what speed do relativistic effects occur? But, like emigrants of centuries past, they would leave the Earth they know forever.
Even if they returned, thousands to millions of years would have passed on the Earth, obliterating most of what now exists. There is also a more serious practical obstacle to traveling at such velocities; immensely greater energies than classical physics predicts would be needed to achieve such high velocities. This will be discussed in Relatavistic Energy.
The distance to the grocery shop does not seem to depend on whether we are moving or not. Examining the equation , we see that at low velocities the lengths are nearly equal, the classical expectation. But length contraction is real, if not commonly experienced. For example, a charged particle, like an electron, traveling at relativistic velocity has electric field lines that are compressed along the direction of motion as seen by a stationary observer. As the electron passes a detector, such as a coil of wire, its field interacts much more briefly, an effect observed at particle accelerators such as the 3 km long Stanford Linear Accelerator SLAC.
In fact, to an electron traveling down the beam pipe at SLAC, the accelerator and the Earth are all moving by and are length contracted. The relativistic effect is so great than the accelerator is only 0. It is actually easier to get the electron beam down the pipe, since the beam does not have to be as precisely aimed to get down a short pipe as it would down one 3 km long. This, again, is an experimental verification of the Special Theory of Relativity.
To an Earth-bound observer, the distance it travels is 2. To whom does an object seem greater in length, an observer moving with the object or an observer moving relative to the object? Relativistic effects such as time dilation and length contraction are present for cars and airplanes.
Why do these effects seem strange to us? Suppose an astronaut is moving relative to the Earth at a significant fraction of the speed of light. A spaceship, m long as seen on board, moves by the Earth at. What is its length as measured by an Earth-bound observer? How fast would a 6. Base your calculation on its velocity relative to the Earth and the time it lives proper time. Thus, the distances in parts a and b are related when. Thus, the two times are related when. An astronaut measures the length of her spaceship to be A spaceship is heading directly toward the Earth at a velocity of.
The astronaut on board claims that he can send a canister toward the Earth at relative to the Earth. Skip to content Special Relativity. Learning Objectives Describe proper length.
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