Reddit mentions of Why Does E=mc2? (And Why Should We Care?)

What you've said is mostly close enough that the difference doesn't matter much to a layperson. However this bit:

> Light does not pass through time (which doesn't make sense to me, but I read that somewhere) which is why it is always moving through space at the speed of light.

Is a bit off while also being a very interesting topic. I imagine the source of this statement is related to the fact that photons will always travel at the speed of light, relative to all observers. In other words, if I were to travel towards you at 0.5c, then shine a light towards you, the light would travel away from me at c while simultaneously (from your point of view) approach you at c, not 1.5c.

In essence, if you assume it to be true that the light moves away from me at c, and towards you at c, the only way to reconcile the two statements is that we experience time differently.

This incidentally is a really good starting point for learning about General Relativity (I heartily recommend the book Why Does E = mc² (and Why Should We Care?) if you find this interesting as it does a way better job of explaining it than I could).

One good example from that book is a thought experiment where you have two observers. One observer is on a train. He has with him an extremely precise clock that simply bounces photons from one plate (bottom) to another (top). For this observer, the photons are going completely vertically as long as the train is NOT accelerating. It critically does not matter whether the train is moving relative to the ground or not, only whether it's accelerating or not. However, to the observer on a platform as the train goes by, the position of the photon as it bounces off the bottom plate, is not directly below the point at which it hits the top plate. It's very close, as the train is not traveling at relativistic speeds, but it's definitely not directly above (picture it as a right angled triangle where the light just traveled the hypotenuse).

This means that even in something traveling relatively slowly, the light has traveled further for the observer on the platform, than for the observer on the train, despite being exactly the same photon traveling at exactly the same speed (c). How much further the light traveled depends on the relative speed. One of the interesting things about this though is that the time dilation effect is actually real and measurable even at relatively slow—certainly achievable—speeds. In fact, it actually effects things we use every day. Flights for example are fast enough that it's measurable, but more interestingly, GPS would not work for more than a few days at a time if the satellites we put in orbit for it to function did not take this effect in to consideration!

Personally, I love learning about quantum mechanics and relativity.

Stuff like this: https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g if you want to watch cool animated explanations of advanced science.

* Almost forgot Fermilab: https://www.youtube.com/user/fermilab

Stuff like this if you want to read laymen textbooks to wrap your head around QM and relativity: (Altho get the paper versions, because they have diagrams and illustrations and stuff illegible on the ebooks):

https://www.amazon.com/Six-Not-So-Easy-Pieces-Einstein-s-Relativity/dp/0465025269/ref=tmm_pap_swatch_0

https://www.amazon.com/QED-Strange-Princeton-Science-Library/dp/0691164096/ref=tmm_pap_swatch_0

https://www.amazon.com/Quantum-Universe-Anything-That-Happen/dp/0306821443/ref=sr_1_1_twi_pap_1

https://www.amazon.com/Why-Does-mc2-Should-Care/dp/0306818760/ref=sr_1_1_twi_pap_2

All of those are mind-bogglingly cool, as well as being actual real science!

Okay. I will remain silent about applications to vectors, but I respectfully disagree. The Pythagorean theorem has a plethora of uses outside of right triangles. For instance, it has important usage in area - and disappointing uselessness in higher dimensions, per Fermat's Last Theorem.

• Oh wait, did I say uselessness in higher dimension? I forgot about its various applications to distance. And that's just in Euclidean geometry - the formula's Minkowski cousin directly implies Einstein's famous mass-energy equivalence expressed in the equation E=mc^2.
  
  I tried writing an essay / short book on all these things, but it was just too much. The links do a good enough job. I recommend everyone read them (and Cox's book, if you're okay with dumbed-down popsci tutorials).

Try this book Why Does E=mc2? (And Why Should We Care?). It does a great job of explaining the concepts in a way that doesn't require a formal education. There is a little math for people who like math, but it isn't necessary to understand.

Brian Cox writes some good books like this. The only one I can think of off the top of my head is Why does E=MC2

But following the links of related titles will probably help you a lot.

The elegant universe is also a really good book... somebody else mentioned it, just want to say that I support that thought. :)

Why Does E=mc2? (And Why Should We Care?)

I just read Why Does E=mc2?: (And Why Should We Care?) by Brian Cox. Can't say I fully understood it all (only an amateur physics buff) but found it very interesting.

Also, Why Does E=MC^2.

I can't speak to your question, but for sure try reading "QED" by Richard Feynman. It doesn't cover the nuclear forces at all, and sadly omits polarization of light, but it is definitely accessible to the HS physics level, and has no scary math.

In fact, his explanation of why he doesn't need scary math to explain QED is as brilliant as anything else he has ever explained!

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Also, I can recommend "Why does E=mc^2 ?" -- will look up author in a bit. The history of science is short, clear, and engaging (to me).


Edit:
http://www.amazon.com/Why-Does-mc2-Should-Care/dp/0306818760