We know what gravity does but do we know what it is other than one of the four forces?

Question

1.gravity, 2.electromagnetism and the 3.stong and 4.week forces

oops, strong. If you don't know either say so or move on.

Answer 1

Nope, we do not.

There is one theory and one hypothesis. The theory is that warped space in the presence of mass causes the energy differentials that in turn cause the acceleration g into the mass.

One of the fundamental laws of nature is that nature is very lazy; it will always try to do whatever takes the least amount of energy. So when space is curved and lower energy levels occur near the mass that curved it, other mass, free to move about, "falls" into those lower energy wells. And, voila, we call that gravity.

This is deserving of the nom de plume "theory" because bent space has actually been observered around massive galaxies. So there are falsifiable observations validating the theory that bent space exists. [Black holes are also bent space, really bent. And they have enormous gravity at their event horizons.]

But, and this is a big BUT, which came first...the chicken or the egg? Did bent space cause the force we call gravity or did gravity cause bent space? If bent space causes gravity, what causes bent space? If gravity causes bent space, then something else must be gravity...not the bent space.

And that "something else" brings us to the hypothesis...gravitons. Gravitons are the messengers that carry the force of gravity (attraction) message to and among all inertial mass. This is just a hypothesis because, to date, there have been no falsifiable experiments or observations to validate this guess.

But on the face of it gravitons make sense because the other three forces (strong and weak atomic, electro-magnetic) have their messengers particles, which have been observed. The W and Z particles carry the strong and weak atomic forces, and photons carry the EM force. So why not a graviton to carry the force of gravity?

Some currently popular theories (that are really hypotheses because no experiments or observations have validated them) predict gravitons. These include quantum gravity and string/M theories. So there are mathematics to support these hypotheses even if none has been validated.

Bottom line, we have some guesses, both validated and not, but no real understanding of what gravity is. Time and improved experimental technology may give us the answer in the near future...or not.

Answer 2

Great question! But the answer is quite detailed and lengthy. Try Leonard Susskind's book 'The Cosmic Landscape'. He writes in depth about how gravity works.

Answer 3

*giggles at Steve* Touche

Gravity is created by any mass. It's just a property of matter.

Answer 4

PLEASE..... Let me know what the other three 'forces' are; Earth, fire, water????