How does the earth maintain its orbit?

Question

Why doesn't gravity pull it in to the sun

Answer 1

Excellent question. The suns gravity holds us in orbit yet the force of the sun's gravity is not so powerful that it pulls us in. Actually the opposite is prevailing we are escaping little by little and one day the solar system will be no more and the earth will go flying off as I guess some sort of space debris. Keep on paying your taxes and your credit bills though, its not going to be for a few billion years.

Answer 2

It's a result of the Sun's gravitational pull on the planet. You may know that an object traveling in a circle is always accelerating towards the center of the circle, and the acceleration is equal to v^2 / r, where v is velocity and r is the radius of the circle. This is called centripetal acceleration. Acceleration can only be caused by a force, and F = ma, where F is force, m is mass, and a is acceleration. So F = ma = mv^2 / r. An oribiting body travels at a particular velocity and a distance from its primary such that the gravitational force between the satellite (in this case, Earth) and the primary (in this case, the Sun) is equal to the centripetal force. The force of gravity is GMm / r^2, where G is the gravitational constant, M is the mass of the primary, m is the mass of the satellite, and r is the distance between them.

So the main equation governing an orbit is GMm / r^2 = mv^2 / r ==> GM / r = v^2 ==> v = sqrt(GM / r), and therefore the orbital velocity of a satellite depends only on the mass of the primary and the satellite's distance from it, with no dependence on the mass of the satellite. Any object orbiting at the same position would have to do so at the same speed.

Gravity doesn't pull the Earth into the Sun because the Earth's motion is such that the Sun's pull keeps the planet moving in an almost circular orbit instead; a circle is the path of an object that is constantly pulled towards the center while already in motion.

Answer 3

It is coasting on momentum left over from its formation billions of years ago. It would coast along in a straight line out into the universe if the gravity of the Sun didn't keep pulling it back. The Earth is moving sideways to the direction to the Sun so fast that before the Sun has time to pull it down, it has gone millions of miles to one side. But all that time that the Sun was pulling Earth to one side caused Earth to curve to that side instead of going off in a straight line. Now the Earth ends up to the side of the Sun but going in a different direction. This just goes on forever to make an orbit. Basically, the Earth IS always falling into the Sun, but it keeps missing to one side because of its high sideways speed.

Answer 4

Put very, very simply there are two forces at work. The sun's huge gravitational effect is pulling the Earth towards it - but at the same time, as Newton's Law of Motion tells us, the Earth is attempting to follow a straight path through space (as anything will unless it is impeded).

So the sun is pulling it in, while the Earth is sort of attempting to escape and this keeps us on a steady orbit.

Answer 5

It would if its orbital speed around the sun were to be reduced by very much.

The gravity tending to pull us towards the sun is balanced by the earth's tendency to fly away from the sun just as a ball on a piece of string can be made to circle your head by spinning it around but If the string breaks it flies off at a tangent.

Similarly, if you reduce the speed you are spinning it at it will start to fall towards your body.

Answer 6

Gravity

Answer 7

The sun is a larger mass then any other object in the solar system, so naturally everything lighter in mass will congregate around that mass. But whats to keep them from getting sucked in? well, as the earth is spinning, its like spinning a unwound yo-yo over your head. you can feel the yo-yo trying to break away from your hand. in this case it is very similar, with the relationship of the earth and sun, except the sun is pulling back with equal force. so everything is blanced, but the earth still rotates.

hope this helps you out!
=]

Answer 8

The gravitational attraction of the sun. The orbit does alter over time, but by a very small amount.

Answer 9

the sun's gravitional pull maintains earth in its orbit

Answer 10

Gravity and momentum. Gravity pulls it in, momentum pushes it out. Tie a ball to the end of a rope and swing it around to get a feel for whats going on.