what keeps the earth in the solar system?

Question

What keeps the earth stationary in our solar system, gravitational pull? if it is gravity, how do comets escape that same pull? is the gravitational pull caused by the black hole at the center of our galaxy? and why doesn't the black hole suck the comets into it?

The differing opinions on this are great, thanks for answering.

Answer 1

K the milky way spins around a black hole continually. It wasn't always that way, as the black hole sucked more and more planets and matter, as well as stars, it had a drainage effect. Thus became the spinning of our galaxy.
Now, what keeps us going around the sun is in fact gravity. Now our Earth is just sitting there, and becasue of that the strong pull of the sun just gradually pulls the Earth around it. Comets on the other hand, move at faster speeds than planets. Imagine, somebody throws a ball by you. If it's going slow you can grab it easily. If it's going fast, it's harder to catch. There are different physics involved of course, but it is a good way to explain it.

Answer 2

According to Isaac Newton, in his 1687 treatise "Philosophiae Naturalis Principia Mathematica" The force applied by gravity is equal to a constant G multiplied by the mass of the first body, multiplied by the mass of the second body all divided by the square of the distance between the two bodies. Newton also demonstrated that the magnitude and direction of the force applied is equal to the mass of the body times its acceleration.

Thus the Earth is constantly accelerating towards the sun! You might ask why the Earth does not fall into the sun if this is the case! Well, if the Earth is travelling past the sun, and an acceleration is applied in the direction of the sun, this will cause the Earth to move in a spiral pattern towards the sun. This is what the Earth's orbit is! You may have already surmised from this explanation that the Sun should also be accelerating towards the Earth. Indeed this is the case, although since the mass of the sun is so large compared to that of the Earth, the accelaration of the sun caused by the Earth is very very small.

Albert Einstein likened the effect of gravity to a curvature of space time. What does that mean? Well if you imagine that space is a rubber sheet, if you put a heavy object on this sheet, such as the sun, the rubber sheet will form a depression where the sun is. Now imagine that you roll a marble along this sheet. The marble's path will be deflected by the depression in the sheet, the marble will experience an acceleration towards the mass. If you flick the marble just right, it will end up circling the rim of the depression - an orbit around the sun just like the Earth. If you flick the marble even faster, its path will still be deflected by the depression, but not enough to stop it from keeping on going off the other side of the rubber sheet. This is how comets, which are very fast moving, are able to escape the solar system. Many comets don't escape the solar system at all, but are just on very very long orbits.

The black hole in the center of our galaxy is what keeps our solar system orbiting in the galaxy. The center of the galaxy is very very far away. So far that it takes 30,000 years for the light from our sun to reach it. Nothing in the solar system even comes remotely close to travelling as fast as the light from our sun, so there is no danger of comets falling into the black hole. The Earth is what keeps the moon orbiting the Earth.

Answer 3

Objects in simple orbits follow paths that match conic sections, that is a circle, an ellipse, a parabola, or a hyperbola. These paths can be viewed as all being of the same type of geometry; just as an circle is simply an ellipse with eccentricity 0 the other two are simply extensions of the same idea.

The path something follows depends on it's velocity and trajectory; moving too fast or not close enough to the central body, and it will escape along a parabaloid path; slower than that it will trace an ellipse.

Some comets do stay in the solar system; Halley's returns to the center where we can see it every 76 years, for instance. Others have much longer return times, many thousands of years.

In short, comets are subject to the exact same forces earth is, but follow highly eccentric orbits.

Answer 4

The Earth isn't really stationary - it orbits the Sun. The Sun's gravity keeps us in place.

Most comets don't escape the solar system, they just have really long orbits so we never see them again. Some do, if they are on a hyperbolic orbit - when they swing past the Sun they pick up enough additional velocity to escape from the Solar system.

We are all orbiting the black hole believed to be at the centre of the galaxy. Although this is attracting us, our velocity is sufficient to stop us falling into it. We're just in orbit and will continue until either the black hole increases in sufficient mass to overcome our tangential velocity, or we are affected by another body which directs us inwards or outwards.

Answer 5

Yes, the gravity of the sun has always kept the current planets in their orbits. Comets can escape the solar system because their orbits are eccentric enough that they can never be "caught" or pulled back in orbit. Instead, they fly out of our solar system, and they probably do get gobbled up by the giant black hole in the center of our galaxy.

Answer 6

Comets are usually small & fast.

Gravity affects them, but their orbit is only slightly changed. Eventually, it does change their orbit enough to cause them to crash.

The black hole in the center of our galaxy is very far away in relation to the comets. It's like saying, why am I not sucked off earth straight into a black hole?

Black holes are very powerful, but good news is, their power greatly decreases with distance. Good thing they are so far away!

Answer 7

the sun's gravity. The bigger the mass and the closer the more force it exerts on something so the sun has a lot of mass and has its own gravity, so it holds our solar system together. That is why the sun is in its orbit held there by the galaxy's gravity. Newton's 2nd law of motion I think.

Answer 8

It's orbit keeps it in place; and comets, and meteors are flying past us all the time, however, we've been shielded by our own moon, and the rest of the planets. Jupiter, and Saturn have been taking a lot of the hits. I saw this on Discovery.

Answer 9

Incase you people didnt already know, there is not evidence of a black hole in the center of the solar system. all they know is that there is a dense cloud of matter, which could be many other things besides a black hole.

Answer 10

The gravational pull of the sun.