WHAT IS GRAVITy???

Question

Ok I know roughly what gravity is, but can you please tell me what it is in a UNDERSTANDABLE detail. (I am an eager yet young student and Im still in high school.

Also if there is only one thing in the Universe, and nothing else, would there still be gravity? Forgetting about the forces inside that object, would there be gravity or not.

Finally can u please explain the "big yawn" or expanse of the Universe to me in a nutshell, in easy language relating to gravity, forces...

Sources will be great! THanks!

Answer 1

Gravity is the distortion of space time by mass.

Here's how it works.

Picture a large rubber sheet. Put a bowling ball in the middle of the sheet.

The sheet is space-time, which is normally flat. Drop a mass into it, and you get a distortion (the bowling ball causes a depression in the sheet), or gravity - the distortion collects other mass and affects light (because 'straight lines' are not really straight.

There would still be gravity in the universe even if there was only one mass - because that mass would distory space-time, causing gravity.

The universe is nothing more than a VERY, VERY large rubber sheet, with all of the masses in it causing those dimples. The larger the mass, the deeper the dimple - black holes cause the deepest ones, where nothing can escape.

Answer 2

Gravity, in a nutshell, is a force; one of the four fundamental forces of our universe, which include: gravity, electro-magnetic (e.g., light and radio waves), and the strong and weak atomic forces that hold nucleii together.

Of the four forces, gravity is the weakest and most pervasive. It keeps you on Earth and the galaxies from flying apart (due to dark matter). If gravity were not the weakest, then when you jump from a ten-story building, you'd crash right through that sidewalk. But the concrete, made up of atoms possessing the other three forces, will actually stop your plumment with a splat. They are stronger than gravity.

Now there are several theories on what gravity is, the real source of that force. One says that it is a subatomic messenger particle called a graviton (string theory). One says it's a bend in space itself (relativity). Another says its just mass pulling somehow on another mass (Newton's gravity). The real enigma with gravity is why the source of gravity (whatever it might be) never seems to deplete?

None of these theories is satisfactory; which is why physicists continue to search for the "real" cause of that force we call gravity. One thing is certain, though, the gravitational force always appears wherever there is inertial mass, the m in E = mc^2.

Thus, if you have just one thing of mass m in the entire known universe, there will be a gravitational field to exert a force on another mass if ever one should show up. But Newton's Law says it does take two to tango; without that second mass, there would be no force of gravity even though there would be a force field.

The "universe" is really two universes: the one we see and all other. The one we see measures back about 14 billion years to the big bang. At that primordial time, all forces were one and the same. In fact, many BB proponents believe there might have been more forces, some of which reached into higher dimensions than the four of today's known universe. But as the universe cooled, the four forces dropped out, like water freezing as the termperature goes down, to exist as the individual forces in our known universe.

We have no clue what lies on the other side of the 14 billion year limit, our cosmological horizon. We speculate that the physics (and therefore the four forces) will be the same as what we have in the known universe. But that's just a WAG because there is no way to validate this guess.

Answer 3

Ok, in an UNDERSTANDABLE detail, gravity is a force, BUT WAIT! All forces must also come in particles, (as stated in the concept of the widely known "wave-particle duality"), so gravity must also be a particle. Many physicist call this undiscovered (at least so far,) particle the graviton. Not that creative of a name, but still ok. So anyway, this graviton can be absorbed and emmitted by all objects with mass to attrace gravitons of other objects. By doing so, the gravitons will accellerate and collide, creating energy, (the force of gravity). Gravity/gravitons make up one of the four fundamental forces (one of the most important forces of nature) of nature. Since gravitons are forces with energy, they add energy to the objects that absorb them, so a bigger object will have more energy object than a smaller one.

This can also be proved with E=mc^2(how?). (Well, the equation says that the mass (m=mass) times the speed of light(c) squared, equals the energy of the object.) Well since the speed of light is 300,000 kilometers per second, squaring that would mean

90,000,000,000*the kilograms in an object = the amount of energy that object has. So much for gravity. One of Einstein's relativity theories (i can't remember which one) says that If there is more motion of an object, then it's time will move slower. (or something close to that.). So if you live 10 billion years on the roof of a sky scraper, you will age faster that living 10 billion years on the ground because there is more gravity closer to the earth. (not that you could live 10 billion years because it is impossible, and in 5 billion years the sun will burn out).

This property of gravity is that gravitons can alter time and space so that the speed of light looks the same to anyone at any point of view. (pretty cool knowing that gravity can warp space eh?). Anyway, Back to the question.

YES YES YES, there would still be gravity because without gravity, that object would not be alble to pull itself together. Gravity also holds objects together. So without gravity, the object couldn't exist

Answer 4

Hi. What it is and what it does are two different things. What it is is also not precisely known. One view is that its force bends the space around it, causing anything that passes through that space to be deflected, even though it continues in a straight line like a photon. Another view is that particles are exchanged between massive objects and this causes the attraction (but without explaining the space curvature). The 'single thing' question is the 'tree falling in the forest' type of question. I guess that answer is "Who cares". The current expansion of the visible universe is possibly the left over momentum from the explosion (or whatever) 13-14 billion years ago.

Answer 5

Gravity is the force from an objects mass pulling onto an object that has a much smaller mass. the earth has gravity from its mass that pulls the moon into orbit around the earth. The reason why we fall back to earth weh we jump is because the earths core generates a force that pulls us towards it, but since there is a crust blocking us from the core, we fall onto it.
if there was only one thing in the universe, gravity would exist, but there would be nothing for that thing to use its gravity to pulls things toward it.
i think you mean the big bang....and its wayyyy too complicated to explain here. but in short: two unimaginably big bodys collided and cause a massive explosion which combined nuclear material to make rocks and on one of those rocks, a cell which divided and divided (keeps going) to create life