Special or General, I LIKE Gravity

So, I'm listening to Einstein's Relativity and the Quantum Revolution (one of The Great Courses I talked about a couple weeks ago) and we're in the heart of it now.

I followed the logic quite well through Special Relativity (SR). I think I could even explain it if someone asked and had a while to listen.

The most recent three lectures have been about General Relativity (GR), however, and the mind boggles somewhat when trying to grasp the consequences. Perhaps someday I will undertake the challenge of taking a full course on GR, though I think I'd need to refresh myself on some math, first. After all, Einstein had to learn the math before he could complete GR. (At least he didn't have to invent the math, like Newton did...)

The funny thing to me is that Relativity (both SR and GR) are very easily expressed, and the words we'd use don't imply relativism, in the philosophical sense. I mean, at the core:

• Special Relativity says "The Laws of Physics are the same in any situation^[1] where motion is constant."
• General Relativity removes the phrase "where motion is constant." Hence, "The Laws of Physics are the same in any situation.^[1]"

So, that doesn't sound very "relative" does it?


The strangeness comes in the implications. Time is not a constant. Distance is not a constant. Gravity, as we all learn it in school (and as Newton thought of it), doesn't really exist -- it's the way we describe the bending of space-time.

This last bit is the hardest part for me to get past so far (even harder than a person aging more slowly when traveling near the speed of light, because I can believe that GR accounts for that.) I like gravity! Gravity makes sense to me.

But, over time, the longer I think about it, the more comfortable I'm getting.

The next lecture is the lecture on Black Holes that hooked me on this course in the first place. I can't wait!


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^[1] They say in any "frame of reference" which is more accurate, but honestly, I think physicists try to make things sound more complicated than they have to at times.