What causes the earth to stay in orbit around the sun?

Answer 1

Gravitational attraction, by the Sun.

Answer 2

There is a mutual gravitational attraction between the Earth and the Sun that keeps it part of the solar system.

Two intricately balanced forces, gravity and momentum, keep the Earth in a stable elliptical orbit. Although Earth is being pulled toward the Sun, its motion relative to the Sun carries it in closed loop around the Sun. Outer space is mostly empty, so there is almost no friction to slow it down, and the Sun's great mass exerts much more of a pull on Earth than the other planets (although these do shape each other's orbits).

Answer 3

The earth has speed that tries to send it flying away in a straight line. It's the force of gravity ... the mutual attraction that draws the earth and sun toward each other ... that bends the earth's path into a closed orbit.

Answer 4

First of all, the Sun does NOT move around the Earth; the Earth moves around the Sun. The _appearance_ that the Sun moves is a trick of perspective. The Earth is spinning like a carousel, and we people riding on it are watching the buildings... I'm sorry, the SUN ... go spinning by. But it's the carousel, or the Earth, doing the turning.

Second, the force that keeps the Earth spinning is its rotational inertia. It _IS_ spinning, and it cannot just STOP spinning unless some force were to slow it down. When you spin a top on the floor, the friction of the floor and the air's friction on the surface of the top cause it so slow down. But there's nothing in space to slow the Earth down!

Answer 5

Every characteristic there is to observe about planetary orbits ... their shape,

distance from the sun, speed in orbit, period of revolution, etc. ... as well as

the paths of comets and asteroids, all follow directly from Newton's formula for

the law of gravity.

You can take that deceptively simple statement, massage it with some calculus

and geometry, and out come equations of motion that almost exactly match the

motions of the planets that we've been seeing with our own eyes for thousands

of years, and measuring with our instruments for centuries.

This is how we're able to fling a package into space from the Earth ... at just the

right time and with just the right speed and direction ... and have it follow a part

of a solar orbit that meets up with Mars six months later.

Answer 6

Every planet moves in accordance with two fundamental physical principles; gravity, and inertia. Each planet is moving, "falling" toward the Sun, but because they are moving sideways, never actually falling TO the Sun. It's a delicate balance.

From our perspective on the Earth's surface, all of the planets "wander" around the sky. In fact, the word "planet" comes from the Greek word for "wanderer"!

Answer 7

This can be explained in several ways; for example:

• There is hardly anything to slow it down. Check Newton's First Law.
• Conservation of rotational momentum. Once again, this relates to the fact that it would require a force to actually slow it down.

Edit: I would answer it like this : There is just one force acting on the Earth

and that is gravity. This force always acts in the direction towards the Sun.

Also the Earth has orbital velocity, tangential to its orbit at any instant. Mathematics shows how these two things combine to produce

the Earth's stable orbit. It's not too difficult, especially if you simplify

things and think of the Earth's orbit as being circular. But you need to be able

to do mathematics called "calculus".

Answer 8

The Earth does not move around the Sun at constant distance and speed. It would if it followed a circular orbit, but instead the orbit is an ellipse, with the Sun at one of the focii of the ellipse. As the Earth falls slightly closer to the Sun it speeds up slightly, as it 'overshoots' and drifts away it slows down again. Isaac newton worked out the equations for this motion when he came up with the theory of gravity in 1687.

Why though does the Earth orbit the Sun, or the Moon the Earth? Gravity is a force of attraction between any two bodies which have mass. If the Earth were placed stationary above the Sun, the force of attraction would pull the Earth and Sun together, and the Earth being less massive it is easier to move so we would swiftly fall into the Sun - just as Newton's apple in the story falls from the tree to Earth. However, the Earth is travelling at speed (very nearly) perpendicular to this pull, and in the absence of gravity would shoot off into space. So, over any small time the amount we fall towards the sun is (very nearly) cancelled out by the distance we would have travelled away from the Sun if we'd kept on going in a straight line. The result is a (very nearly) circular path.

Answer 9

Gravity keeps the Earth and all the other objects in our solar system moving around the sun. The sun moves around the galaxy, and stays in orbit due to the gravitational pull from either what is in the center of the galaxy or all of the other stars in the galaxy, or possibly both.

Answer 10

It's current velocity.

It is hard to describe in words, however. basically the Gravity of the Sun is always pulling us (the Earth) towards it. But we are traveling so fast, that if we look at it in several snap shots and pretend that our current orbit is a circle it can be described somewhat.

If there was no gravity, you picture Earth just moving in a straight line going from the edge of the circle away from it like the stem on the letter "d" (but if the round part on the "d" was more of a "o" then a "c").

Well, as the earth runs from this circle, the gravity of the sun pulls the earth back, but it only pulls the earth back to the surface of the orbit, before the earth starts running away again. This process repeats and repeats over and over, with the earth trying to run away and the sun pulling it back, causing it to spin in a circle.

If the earth isn't running fast enough, then the sun can pull it a little closer every time, and eventually gobble it up. If the earth is running too fast, then the sun doesn't quite pull the earth back before the earth runs again and eventually the earth will run away. We just happen to be at the write speed to not get sucked in and not run away.