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Casey Miller
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Post any thoughts or ideas here.
Casey Miller said:Why does distance change as objects go closer to the speed of light?
nitsuj said:Because of the first postulate in SR.
The laws of Physics are the same for inertial observers.
AMoore94 said:Good question. My thought-experiment explanation of why time distorts as objects approach the spped of light:
Imagine a single particle of light bouncing back and forth between two points on a platform. The point of the viewer is a relatively motionless platform in space. As the platform with the point of light begins to move, the path of the particle of light becomes more and more horizontal. As the pythagorean theorem shows, the distance required to travel that triangular space is now longer than before, when the platform is stationary. And because the speed of light remains the same in all frames of reference, the time that is required for the light to travel that distance is more than before. Thus, the time distortion seen as anything approaches the speed of light.
This explains time distortion, but not space distortion, although I suspect that they are based on a similar thought process.
Casey Miller said:Yes. I underdstand the equation and how it is derived, but is there a theoretical or observable reason that it can be explained without an equation?
Casey Miller said:Okay, now Albert also talks about how anything can be refrenced as at absolute rest compared to other things. Such as a cup on a table. Everything moves around this cup. But now let's place the cup in the air 100 meters above the table. We still hold true the fact that the cup is at absolute rest, and we let go. Albert states that instead of saying gravity has effected the cup, he states the Earth accelerates at upward at 9.8 m/s.
But then we have an explinaton that anything that has a push or pull cannot be at rest and then is therefore in motion and not in absolute rest. How does he institute this possibility of a explainable counter-effect of gravity?
nitsuj said:Be careful with feeling you understand it and how it was derived.
I suggest thinking about what speed really means. From there consider how there is a maximum speed, and that all inertial observers measure it to be the same.
distance / time
whether staying at rest relative to me or if you travel at 0.5c relative to me, you will always have the same proper time. your time measurement appears the same to you. To me, your proper time appears dilated (slow). I know that your calculation of the value of c will be the same as me. I have to conclude that in addition to your proper time being dilated, your measurement of distance is effected as well.
An easy way to visualize it is to imagine you are piloting a disco ball ship in space at some speed close to c relative to me.
you emit a "pulse" of light in all directions around you.
Because c is constant, your perspective will be that the light around you is all equal distance away from you (as in your ship is right in the middle of the light pulse circle) despite the fact that you are moving towards the light pulse infornt of you and away from the light pulse behind you.
However because c is constant, my perspective is the light you are traveling towards is less distance to you then the light you are traveling away from.
Casey Miller said:I agree. Also, do you know anything about what is said about the size of the universe? I was reading about how it is tied to the average density in the universe?
An inertial frame of reference is a coordinate system in which Newton's first law of motion holds true - an object will remain at rest or in constant motion unless acted upon by an external force.
In an inertial frame, objects follow Newton's laws of motion without the need for any additional forces. In a non-inertial frame, objects may appear to move in ways that do not follow Newton's laws due to the presence of external forces such as gravity or acceleration.
The principle of relativity states that the laws of physics are the same in all inertial frames of reference. This means that measurements of motion and forces will be consistent across all inertial frames.
Einstein's theory of relativity builds upon the principle of relativity by extending it to all frames of reference, including non-inertial frames. It also introduces the concept of spacetime and how it is affected by mass and energy.
Inertial frames of reference provide a standardized and consistent way to measure and analyze motion and forces. This allows for more accurate and reliable results in scientific experiments and research.