RE: I simply can not get my head around gravity.
I don't have a scientific background. But if it helps:
Newton's laws don't tell us what gravity is. They just describe what gravity does. And they only do that in very limited situations.
Say you need to pick someone out of a lineup. There's five guys, and one girl. All I need to tell you to pick the girl is, simply, 'the suspect is a girl.' There.
I haven't told you everything about her. Just enough to describe her for our particular situation. That's Newton's laws...actually, that's nearly all scientific theories. They work very well for specific situations, but there's always some extreme situation in which the laws break down. And that's usually a sign that you need an updated set of laws.
To further the analogy, if the lineup is all female, telling you 'the suspect is a girl' just isn't going to cut it. Now you need descriptors - hair color, eye color, height, weight, ethnicity, etc. You need things to get more detailed and complicated.
Gravity is one of those 'more detailed and complicated' situations.
The best explanation, as far as I know, came from Einstein. He described gravity as a disturbance in the fabric of space. Which makes some sense - gravity acts at a great distance. Other forces do not. It acts proportional to mass - i.e., if an object is more dense and bigger, it attracts other objects with greater strength.
Picture a golf ball and a bowling ball on a bed. They will both indent the covers, but the bowling ball will also indent the mattress. Now picture a marble rolling next to either the golf or the bowling ball. The marble's path will be altered slightly by the golf ball's indentation, and much more by the bowling ball's indentation.
It's hard to picture a 3-dimensional fabric of space, but the math to describe the bed and gravity is nearly the same.
Thank you for your answer.
I have seen the explanations for the "madras" example, but i believe they describe 2 different forces.
And i have also read/seen many many descriptions from people who try to explain Einstein`s theories, but it have become clear to me that most of them have misunderstood him.
That is why there for example is many people who actually believe that Einstein said we could travel in time, almost like Doctor who, because they did not understand that it was one of the effects of light he was talking about.
So to avoid all those misunderstood explanations for Einstein`s theories, i have decided to read his original writings my self.
But those who believe they can just start to read those papers, and understand what he actually said, have probably never tried to do that.
To be able to read those and actually understand what he said, one need a lot of background knowledge.
One of the first things i discovered that i fully need to understand before i can understand his writings, was electrodynamics.
But to be able to understand electrodynamics again, it is necessary to understand Algebra, calculus and classical mechanics..
So that is what i am reading my self up on now, to be able to go on reading his papers.
And my guess is that when i fully understand this things, i probably will have to learn even more things to understand his next chapter.. lol
But i know it will be worth it in the end.
But for now, i have learned that it is a must to fully understand Algebra, Calculus, Classical mechanics and electrodynamics just to be able to understand the first chapter.. ;)
Simplified explanations on Einstein or Bohr`s paper work are almost doomed to be both wrong and misunderstood.