How does gravity work in space

The metrics is a tensor which describes the difference between one meter in the x direction and one meter in the y direction, or one meter near the sun and one meter far away. These differences are coded in the form of coefficients which you stick into the equation describing a straight line et voila, the equation now describes a curved line. In reality, things are more complicated, Because the sun cannot affect the earth at a distance but through the exchange of energy and momentum, that exchange being made by the emission and reception of gravitational waves, of, in quantum language, of gravitons.

How does gravity work in space? Mar 23, The same as anywhere else. Explanation: Every particle in the universe has a bit of gravity.

Jul 21, Gravitation curves space-time. Explanation: Peter gave you the classical answer. Image credit: NASA. Anything that has mass also has gravity. Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass.

All its mass makes a combined gravitational pull on all the mass in your body. That's what gives you weight. And if you were on a planet with less mass than Earth, you would weigh less than you do here. You exert the same gravitational force on Earth that it does on you. Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. The gravitational pull of the moon pulls the seas towards it, causing the ocean tides.

The reason gravity pulls you toward the ground is that all objects with mass, like our Earth, actually bend and curve the fabric of the universe, called spacetime. That curvature is what you feel as gravity. Spacetime is exactly what it sounds like: the three dimensions of space — length, width and height — combined with the fourth dimension — time.

Using some very brilliant math, Einstein was the first person to realize that the laws of physics work in a universe where space and time are merged together. What this means is that space and time are connected — if you move really fast through space, time slows down for you compared to someone who is moving slowly.

This is why astronauts — who are moving very fast in space — age a tiny bit more slowly than people on Earth. Remember, gravity is the idea that objects in the universe are attracted to each other because spacetime is bent and curved. When Einstein came up with general relativity, he showed that all stuff in the universe can curve spacetime — in physics terms that stuff is mass and energy.

Since your brain usually thinks about the world in three dimensions, it is really hard to think about the four dimensions of spacetime as a single idea. It was part of his famous General Theory of Relativity, and it offered a very different explanation from Newton's Law of Universal Gravitation. Einstein didn't believe gravity was a force at all; he said it was a distortion in the shape of space-time, otherwise known as "the fourth dimension" see How Special Relativity Works to learn about space-time.

Basic physics states that if there are no external forces at work, an object will always travel in the straightest possible line. Accordingly, without an external force, two objects travelling along parallel paths will always remain parallel. They will never meet. But the fact is, they do meet.

Particles that start off on parallel paths sometimes end up colliding. Newton's theory says this can occur because of gravity, a force attracting those objects to one another or to a single, third object.

Einstein also says this occurs due to gravity -- but in his theory, gravity is not a force. It's a curve in space-time. According to Einstein, those objects are still travelling along the straightest possible line, but due to a distortion in space-time, the straightest possible line is now along a spherical path. So two objects that were moving along a flat plane are now moving along a spherical plane.

And two straight paths along that sphere end in a single point. Still more-recent theories of gravity express the phenomenon in terms of particles and waves. One view states that particles called gravitons cause objects to be attracted to one another.

Gravitons have never actually been observed, though. And neither have gravitational waves , sometimes called gravitational radiation, which supposedly are generated when an object is accelerated by an external force [source: Scientific American]. Gravitons or no gravitons, we know that what goes up must come down.

Perhaps someday, we'll know exactly why. But until then, we can be satisfied just knowing that planet Earth won't go hurtling into the sun anytime soon.