Since the sun has a gravitational pull, why and how do the planets orbit around it and not just get pulled in?

Answer 1

Everything that's orbiting the sun has reached just the right tangential velocity so that when it gets pulled back towards the sun, it has just enough velocity to not get pulled any closer.

The ones that don't have enough tangential velocity are (sometimes slowly) falling towards the sun.

Please see the source for a better illustration.

Answer 2

Since the sun is also rotating about its axis, a body near the sun's surface will experience two forces.One is the gravitational force which tries to pull the object towards its centre and another is the centrifugal force or outward-moving force(created due to the rotation) which tries to push the object away from the centre.Near the sun's surface,the gravitational force is more than the centifugal force and the object will be pulled towards it.
But the gravitational force decreases inversely as the square of the distance of the object from the centre of the sun.At great heights,therefore an object like a planet experiences weightlessness when the low gravitational force is offset by the action of the centrifugal force and hence the sun is not able to pull the planet.
The revolution of the planet must have originated at the time they formed from rotating gaseous nebula.As there is no resistance to the motion of the planet around the sun in the space, it continues to revolve around the sun.

Answer 3

Because the planets all have orbital velocity, which effectively means the planets are in a free-fall around the sun as the outward velocity of the planets offsets the pull of the sun. Same thing happens when we put something into orbit around Earth. It's not floating.... the object, whether it's a satellite or the space shuttle, has a speed of about 5 miles/sec, which obviously calls for it to be above the Earth's atmosphere, lest wind resistance begin to slow it down (see Skylab). This matches the pull of Earth's gravity when there is no air resistance. That's how things stay in orbit and not plummet back down to Earth. Same principle for all things that sustain an orbit around a larger body.

Answer 4

Imagine a ball rolling off a table - it will travel a little distance horizontally before it hits the ground. Now imagine that the table is a bit higher or the ball is moving a bit faster, and the ball will travel a bit further before hitting the ground. Now imagine that the table is a thousand miles high, and the ball is travelling at several thousand miles an hour. The horizontal distance travelled by the ball before hitting the ground will be greater than the radius of the earth. That is, it will never hit the ground, but go into orbit instead. The same effect prevents the earth from ploughing into the sun.

Answer 5

If you have a moving body travelling in the field of a central conservative force like gravity or electromagnetism then its trajectory will be a conic section..ie a circle, ellipse, parabola or hyperbola. To show this equate the gravitational (or conservative force) to the rate of change of momentum of the body. The solution is one of the pedal equations for a conic section. Only certain orbits (f(v,r)) result in a collision with the central mass. The solar system, although it displays small scale chaotic behaviour can be shown always to follow the envelope of a strange attractor and will ultimately return to equlibrium. This assumes no external perturbing forces and that the solar mass does not change catastrophically (ie flaring into a red giant) I think Laplace proved this mathematically in the late 18th Cent.
And although Laplace did not take into account special relativity, I think it even applies to the situation where the planets mass changes due to its speed and hence the grav force. All that happens is that the planet orbits precess...

Answer 6

There are two things involved --
1. the sun's gravity is trying to pull the planets into it;
2. the planets all try to move through space in a straight line

Each of those two factors effectively cancel each other and the result is the planets move around the sun.

Answer 7

It is their forward motion which keeps them from being pulled in: centrifugal force, if you like. They are in a constant state of free fall, but moving forward at a speed which keeps them from getting any closer.

Imagine shooting a bullet parallel to the ground. It will curve downward and hit the ground at some distance from you. But the earth curved down just a little bit. Now you shoot a much faster bullet. It falls, too, but the earth has curved away from its path a little more this time. Now imagine shooting a bullet so fast that the ground curves away from it at the same rate it falls. It would never hit the ground unless it slowed down. This would be impossible in our atmosphere, but not in space where the resistance to forward motion is nil. That's what the planets are doing as they orbit the sun.

Answer 8

They are constantly being pulled in.
But they are travelling exactly fast enough perpendicular to the source of gravity to miss the sun and stay at the same distance.
Its difficult to explain.
Its the same thing that happens to astronauts. People think that gravity stops at the edge of the atmosphere. It doesnt. The curved earths surface falls away at the exact same rate they fall. To manage this you need to be travelling fast.
Theoretically its possible to be weightless a few inches off the ground if you could travel at 17000mph in the atmosphere.
Astronauts dont float, they fall with style.

Answer 9

Because (very simply) the sun's gravitational pull is counterbalanced by the Earth's natural inclination to move in a straight line as predicted by Newton.

It's kind of like if someone had hold of your arm and was trying to pull you towards them and you were trying to get away, you'd end up moving in a circle around them.

Answer 10

The planets are being pulled towards the Sun continually and in approx a billion years or a million years (I think) the planets, one by one, will be burned up by the Sun and disintegrate. The Sun in time will lose its heat and die also.