I'd like to learn more about gravity. I once heard Carl Sagen say it is the weakest force, and yet we can't get away from it. He proved his point by picking up a rock, yet that didn't break gravity, it just transferred mass from the ground to his hand. It fills all of space, even astronauts in orbit are bound not only to the earth, but to the sun, the Milkey Way, and the Great Attractor.
This hardly feels like a weak force.
It is actually a very weak force. For instance and to illustrate it, take a tiny magnet, Put it on the ground. The entire gravitational force of Earth keep this little piece of magnet on the ground. Take a second tiny magnet and approach it towards the first one. This second tiny magnet will attract the first one... It is stronger than the entire planet :)
The fact that we really feel gravity is that this force is not screened, in contrast to some other forces, and that its range is infinite. For more information, maybe could you have a look into this post I wrote 2 months ago. You can also directly ask me (or @williambanks) for more ^^
It is kind of strange when you think about it though @lemouth After all, that works lovely here on earth, but on a neutron star it probably wouldn't work and no amount of EM is going to pull something once it's past the event horizon of a blackhole regardless of how strong that EM field is.
Gravity has overcome every other force in that instance. For that matter though, do we even have a solid theory about how magnetars gain their immense magnetic fields?
My example indeed only works on Earth :) It was only an example.
We must be careful here as we are talking about two different things: gravitational interactions in general and gravitational effects that are the results of the interactions.
The magnitude of any resulting gravity effects is indeed given by the product of the strength of gravity and the involved masses.
I hope this clarifies ^^
PS: for the magnetars, I don't know, but I would check in this one.
I think @casandrarose is trying to point out that there is no way for us to get away from gravity. Sure, the magnets move toward each other, or the lower magnet moves up a few inches, but as they move, they are still bound to the earth, the sun, and the Milky Way. No one has ever been free from gravity.
I'd be curious to know what being truly free of gravity would do to how we measure time. Or how we could become free of gravity.
I agree :).
I was actually not referring to being free from gravity, but more only about beating gravity on some short scales. As I said, gravity is not screened and its range is infinite: we cannot escape it ^^