Carson: Gravity, where does it come from?

[Ljube]

Exactly. Nobody knows where gravity comes from.

[Ljube]

Yes, we know far more about the properties of gravity than what generates it. Ditto for electricity I think. I remember pushing my science teacher in High School about this very issue. The teacher was made quite uncomfortable. It's all about the difference between science and technology, with the latter more focused on how it works, than why it works.

That's true. I graduated electrical engineering and we don't know where electricity comes from and we know where gravity comes from even less.

However, we know that electricity and gravity both exist. We're not entirely sure how they work, but we are pretty sure that in most cases we can approximate their work using mathematical formulae.

Bottom line, Carson is right. And nobody who knows anything about gravity or electricity can claim otherwise.

[Ljube]

It hasn't been unified with quantum mechanics, but we do know where it comes from.

That's a rather big caveat. Either there has to be something gravity "comes from" consistent with quantum mechanics (and which has not yet been discovered), or our current understanding of quantum mechanics and/or general relativity must be incorrect. The latter is very unlikely, so it's fair to say that it isn't known "where gravity comes from."

But at most that will result in tweaks to the theory, which do not obviate its accuracy or its explanation at non-microscopic scales. We may get a grander understanding of gravity, but it's not going to blow out of the water the basic explanation for why the apple falls from the tree. Before Einstein, that really was a mystery.

Actually, before Einstein most scientists would not have thought gravity to be a mystery. Scientists in the 1800's would say that gravity comes from pairs of masses interacting at a distance according to Newton's law of universal gravitation. In much the same way they would say that electrical forces came from two charged objects interacting at a distance. (Inter)Action at a distance was a well accepted principle by then.

The mystery to theorists in the 1800's was how to prove the mass in Newton's law of gravitation was the same as the mass in Newton's 2nd law of motion (F = ma). Einstein solved that with general relativity by applying the equivalence principle that an accelerated frame of reference was indistinguishable from being in a gravitational field.

Wasn't it a mystery why masses had this property that they could interact at a distance?

It is still a mystery.

[Ljube]

The inverse-square relationship applies to both.

Yes. The inverse square relationship is the kind of clue one needs when trying to create a Unified Field Theory. I believe that we will be able to accomplish that one day.

In the meantime, we'll have to get by with the kinds of half-baked theories, such as Newton's and Einstein's, which work most of the times, but are not universal.