From 3.5 billion Reddit comments

1 point

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11th Aug 2017

Looks good.

What textbook are you using? Is your instructor taking a geometrical approach to special relativity or are they going for the algebraic approach (ie, have you spent a lot of time with space-time diagrams or not?). If you aren't using it I highly recommend Spacetime Physics, and if you can't spring $80 for a textbook I'm sure a resourceful person could easily find a pdf somewhere.

1 point

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17th Apr 2016

You're welcome.

If you're really looking to dip your toes into special relativity, I strongly recommend Taylor and Wheeler's <em>Spacetime Physics</em>. The writing style is a little idiosyncratic, but it's a brilliant book for beginners. As far as I'm concerned it has no rivals in that department.

1 point

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26th Jul 2018

I like this textbook. It takes a friendly and fairly whimsical approach. However it is still a textbook, and it expects you to do the maths and attempt the exercises. I'm not sure about a good pop-sci book unfortunately.

Edit: The old edition is available as a pdf on Taylor's website, because it looks like the new one gets pretty expensive on Amazon.

1 point

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4th Dec 2017

This is basic undergrad coursework. It's not really debatable. I'd recommend this textbook if you're really still confused about this sort of thing.

1 point

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21st Mar 2017

I have been recommended Spacetime Physics by Taylor by my colleague. Apparently it is very accessible to undergraduates (in terms of mathematics). I have another book but it is packed up and honestly I haven't touched it since my senior year.

Edit: A quick Google search found my text. https://play.google.com/store/books/details?id=GgRRt7AbdwQC&source=productsearch&utm_source=HA_Desktop_US&utm_medium=SEM&utm_campaign=PLA&pcampaignid=MKTAD0930BO1&gclid=CJisjNvW5tICFYyjNwodJcwBOQ&gclsrc=ds

1 point

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22nd Feb 2017

You always move through time at the same rate, 1 second per second. What changes in special relativity is that we stop being able to agree on time measurements with other observers who are moving with respect to us. You can't just slap time on as an extra axis like you would with Z when moving from 2D to 3D. The very rules of geometry change when you switch from space and time to spacetime, and they do so in such a way that even though different people disagree on the amount of time that passed and the distance between things they can always agree on special quantities that are 'invariant' and we can use those invariant measurements to bridge the measurements of two observers.

In 2D when you want to know the distance between two points you can find the x position and the y position of each point and use basic trigonometry to find the distance. a^2 + b^2 = c^2 . Let's say you want to know all the points exactly one unit away from the point (0,0), you just set c = 1 and find values of a and b that still fulfill that relation. You will find that neither a nor b can be greater than 1 or less than -1 by itself, or the point will not be 1 unit away. This is relatively easy because we can freely add together the values of a and b. But what if we measured a in meters and b in miles and we didn't know how to convert those units? We could never do this basic geometric exercise, we could still refer to a given point but we could not find all the combinations where c = 1.

That is the basic problem with just tacking time on as another axis. Time is measured in seconds, and that as a unit is not compatible with meters. So we need a conversion factor in order to measure time in units of meters, it turns out the speed of light is exactly that conversion factor we need and that has some fun consequences that I don't have the time to go into. If you are interested in special relativity I highly recommend finding a copy of Spacetime Physics by Taylor and Wheeler, if you followed my argument above and have some very basic physics you should have relatively no problem with the first few chapters which should help you understand relativity much better.

0 points

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28th Oct 2019

> I am very familiar with classical mechanics but not relativity at all

In that case, this is an excellent (and modern) introduction to special relativity:

Spacetime Physics: Introduction to Special Relativity

https://www.amazon.co.uk/dp/0716723271/

An older but equally excellent introduction is by Einstein himself, and it’s in the public domain so you can find it for free,

Relativity: The Special and the General Theory

(paid) https://www.amazon.co.uk/dp/B00R86QABW/

(free) http://www.gutenberg.org/ebooks/5001

Finally, if you allow me to make a plug for myself, I’ve written a few posts here on Reddit that give the gist of the ideas behind both theories. They start here:

https://www.reddit.com/r/Physics/comments/dnexh8/question_about_gravity/f5ab0w1/

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