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1 point

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11th Aug 2021

If you're curious, there are a lot of introductory special relativity books that are mostly accessible that cover this in particular and similar "paradoxes"

I learned from this guy, https://www.amazon.com/Special-Relativity-T-M-Helliwell/dp/1891389610, though not using this book. Most of the examples were of relativistic rhinoceri

1 point

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17th Mar 2021

I'm going to make a only tangentially related suggestion, because general relativity is exceedingly hard to simplify down to anything at all without an extreme amount of math.

Take some time and learn special relativity first with some actual detail. Special relativity at its core relies on geometry and algebra (the algebra will likely be tricky but not completely beyond your grasp at your age) and will set up the framework to answer some of your questions about time and light. It won't address gravity - that's what general relativity brings in - but it should be a lot more approachable to you at 14.

You might find this textbook a good starting point as well. It's designed for a first-year college student but it's really easier than that, I think, and assumes very very little prior knowledge, at least for the first few chapters (1-7) which are really the relevant ones to starting to answer your broad questions anyway. The later ones will expect a lot more from you.

The short answer is this, and this is basically from that book summarized (since that's the textbook I first learned from): Relativity (either special or general) relies on one core rule, that the speed of light must be a constant. Any changes to distances light travels (either based on the motion of observers/objects or the bending of space itself due to mass) must therefore be balanced by adjustments to time elapsed, such that the speed of light remains constant no matter what.

In our "normal" physics, we assume that time is the thing that stays the same for all, and any adjustments to distances are balanced by corresponding changes to velocities to keep time the same for everyone (this is the Galilean velocity transformation). Basically, all relativity does is change that fundamental rule and then logical deduction gets you to the surprising conclusions inescapably.

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