On Sun, Oct 28, 2018 at 8:12 AM <agrayson2...@gmail.com> wrote:
> > *the Eastern mystics could very well be right that the external world > is illusory.* Mystics love to say stuff like that because they think it sounds deep, but I don't think it is because they never explain how the illusion works, they don't even know what they mean by "illusory"; they can't say how things would be different if the external world were NOT illusory. > In my view, what's primary is space which somehow produces restrictions > on directions of motion, The idea of change is meaningful only if its specified over what dimensions the change is occuring. Motion is a change in the position in space with respect to time, you can't have motion without both space and time. That's why Hermann Minkowski, Einstein's mathematics teacher and the discoverer of Spacetime, said "*space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality*". >* Inverse square is a good approximation for weak field gravity. Why not > posit universes with inverse cube, and so on as possible universes?* Actually string theory does posit something like that and uses it to explain why gravity is so much weaker than electromagnetism or the nuclear forces. It says there are 10 spatial dimensions but unlike the 3 we are familiar with 7 are tightly curled up so if you moved along one of those dimensions a microscopic distance you'd end up in the same place. It says gravity radiates into those other dimensions and so weakens by a inverse 9th power when things become close. Unfortunately string theory doesn't specify exactly how curled up those dimensions are, it doesn't say how close is close and there is no evidence any of this is true. We know experimentally that the inverse square law is true for distances greater than 1 mm but at distances less than that it's too hard to measure gravity to know what's going on. However we might find evidence those other dimensions exist from particle accelerators. If those 7 additional spatial dimensions are small by human standards but much much larger than the Planck Length then when 2 protons are forced to get so close that the distance approaches the size of those small dimensions then gravity would no longer be a inverse r^2 law but a inverse r^9 law; push the two particles just a little bit closer and the gravitational force between them becomes enormously stronger. And then you have a shot at making a Black Hole. The idea is that at these very small sizes gravity would be just as strong as the other forces of nature, only at larger sizes is gravity so much weaker than the other forces because it leaks out into the other 7 dimensions and gets diluted. The other forces don't go into these other dimensions and so don't get diluted. But as I said nobody knows if any of this is true. Such a sub microscopic Black Hole would not be dangerous because the smaller the Black Hole the hotter it is and so it would evaporate away by Hawking radiation in about a billionth of a billionth of a second. But if we made one it would be easy to detect by its decay products, and if our accelerator was smaller than the galaxy we'd know there must be extra dimensions and they are larger than the Planck Length or we wouldn't have been able to make a Black Hole. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
