Can you prove what gravity is, a wave or particle? What is the attractive force made of scientifically?

Question

I think was told in college physics that gravity is a hypothesis or theory and as not been proved to exist. Is this true?
Are there other things in science like this?

Answer 1

We don't really know. We can define what it is as a field of influence, because we know how it operates in the universe. And some scientists think that it is made up of particles called gravitons which travel at the speed of light. However, if we are to be honest, we do not know what gravity "is" in any fundamental way - we only know how it behaves.



Here is what we do know...



Gravity is a force of attraction that exists between any two masses, any two bodies, any two particles. Gravity is not just the attraction between objects and the Earth. It is an attraction that exists between all objects, everywhere in the universe. Sir Isaac Newton (1642 -- 1727) discovered that a force is required to change the speed or direction of movement of an object. He also realized that the force called "gravity" must make an apple fall from a tree, or humans and animals live on the surface of our spinning planet without being flung off. Furthermore, he deduced that gravity forces exist between all objects.



Newton's "law" of gravity is a mathematical description of the way bodies are observed to attract one another, based on many scientific experiments and observations.

Answer 2

The word "theory" in science has a very specific meaning. It doesn't mean "guess" or "wild conjecture" or "baseless speculation".



A theory is a robust model that give a general picture of how a large group of somethings work. This model has to be verified by multiple lines of evidence to rightfully claim the title of "theory". Its an idea that not only has something to say about the way the world works, but the things it says are testable and those test show that the idea has merit.



Gravity, itself, obviously exists. The fact that we don't float away leads to this conclusion.



Now the interesting part is that physics has two really, really good fundamental theories. One is Quantum Field Theory, which does an incredibly good job of predicting and describing the nature of the atomic and subatomic world.



The other is General Relativity, which does a really good job of explaining not only how gravity works, but the funny phenomena like the gravitational bending of light and the way the binary pulsars emit gravity waves. General Relativity has been verified by every test anyone so far has imagined and tried and has passed with flying colors.



The trouble is, these two incredibly good theories have never been successfully combined. So we know there is a bigger theory out there that incorporates both ideas, just nobody knows what that idea will be precisely.



Roughly speaking, the basic idea of General Relativity is that gravity is a bending of space-time caused by matter and energy.



Now, if these ideas excite your imagination, I recommend starting with Richard Feynman's book QED: A Strange Theory of Light and Matter. It doesn't talk about gravity at all, but it will introduce you to the ideas of quantum electrodynamics, the first quantum field theory to be produced.

Answer 3

Neither.



Gravity is one of the fundamental forces, of which there are four. These are: (from weakest to strongest) gravitation, the weak nuclear force, electromagnetism, and the strong nuclear force. These four forces govern all interactions between matter and energy in the universe, and the space in which they influence each other is known as a "field". (gravitational field, electromagnetic field, etc.) For example, when one object collides with another, it isn't actually the objects touching each other; it is the strong nuclear force, which prevents particles from passing through other particles. (Although it is the strongest of the four, it only has noticeable effects at extremely close distances.)

If it weren't for the strong nuclear force, particles such as protons and neutrons(hadrons) would pass right through each other instead of bouncing off.

The strong nuclear force is also responsible for nuclear fusion: when two particles are forced closely enough that this force is overcome, it results in them annihilating each other and releasing energy. (Their mass is converted into energy. Matter is actually energy itself; just very concentrated.)



So gravitation, the weakest of the four, is responsible for gravity. (The difference being that gravity applies only to the attractive force of the earth, whereas gravitation is the attractive force between ALL matter.)

The reason we only observe the gravity of large objects such as the earth or sun is because gravitation is incredibly weak; so it's only noticeable when there are enough particles together for their collective gravity to have a significant effect on other nearby matter(i.e., meteors, the moon, us).



Gravitation is also responsible for the fusion reactions in stars.

When enough particles combine for their collective gravitational force to be greater than the strong nuclear force keeping them apart, the particles will be pulled into each other, becoming energy. Their gravity will remain, so the reaction will continue. Incredible amounts of energy will be constantly released until there are no more particles left to continue the reaction. This is known as a star.



This explanation is very basic; the study of the strong nuclear force and its interactions is called Quantum Chromodynamics, and it is one of the most complicated fields of study known to man.



I hope that answers your question; thank you for taking the time to read this.





P.S. - For a more detailed explanation, go to Wikipedia and look up "Fundamental Forces".

P.P.S - In the answer written by the gentleman above, gravity waves are briefly mentioned. In case you were wondering what that is, it is a brief fluctuation in a gravitational field that propagates like a wave.

Answer 4

it particularly is not. It in basic terms looks that way. Nicolas has the perfect concept. The regulation of gravity is incorrect!!! we've prevalent this for some time now, yet we nonetheless use it to describe the way products behave by using fact it particularly is sturdy sufficient for ninety 9% of the issues every person is coping with. Technically you may say gravity is a repulsive stress the place area pushes lots jointly.