Why doesn't sun's gravity pull Earth into itself?

Question

Why doesn't sun's gravity pull Earth into itself?

Answer 1

inertia, we are moving too fast.

Although, the earth is actually slowly falling into the sun, so eventually we will fall in.

Answer 2

Like I asked my physics teacher when I first understood orbits "So the orbiting the Earth is like falling... but missing?"

My physics teacher found this amusing because one would think a falling object is certain to hit the ground. Try dropping a hammer... 9 times out of 9.00000000001 it will hit the ground.

Circular orbits like the path of the space station are possible because it has just enough tangential velocity (velocity in a direction perpendicular to the pull of gravity) to miss the planet. Think about shooting a gun in space directly above Earth. The bullet wouldn't fall straight down, it would arc to the ground. Now increase the velocity of the bullet, the bullet's arc will get bigger and the bullet will travel farther before hitting the ground. Now increase the velocity so the bullet only just misses the Earth. It should start getting pulled around the Earth. It doesn't have enough velocity to escape Earths gravity but it does have enough to avoid hitting the surface.

Earth follows these same lines when orbiting the Sun. During the Earth's formation it found that perfect speed for its particular distance from the sun and has been orbiting ever since.

Answer 3

Because Earth also has a force moving it tangent to the curve.  So the Sun's gravity does pull Earth toward it, but it's counteracted by this tangential force, making it orbit in a path like a circle (actually an ellipse).

In a way, it's like the Earth is constantly falling toward the Sun, but missing.  That's the same way the space shuttle orbits the Earth.

Answer 4

because the earth is not nearly close enough to be subjected to THAT strong a force of gravity.  the planets in our solar system are under a pull of gravity that, combined with the velocity of the planets, allows them to stay in orbit with the sun without really getting closer to it.  get much closer than mercury though and the gravitational force would probably pull you into it.

Answer 5

How do you think the Sun's gravity would pull Earth into itself? The Sun's gravity makes our planet orbit it, these are the physics called 'orbit'.

Answer 6

Actually, the answer is very simple. Inertia.

Inertia is the tendancy of an object to resist motion. The more matter, the more inertia.

Earth has so much mass that its inertia is great enough to prevent itself from being pulled into the sun.

Now, objects with little inertia, like an asteroid, are constantly being pulled into the sun because they don't have enough mass to have enough inertia to stop themselves from being pulled in.

Think of it this way, which has more mass, a bowling ball, or a marble? Obviously a bowling ball. Which is harder to move, a bowling ball or a marble?

Answer 7

The sun is pullling the Earth into itself.  But the Earth is also moving laterally at the same speed.  The end result is a (nearly) circular orbit.

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Answer 8

Gosh, either people get too techy or they get it wrong..

All orbiting bodies, whether satellites round the Earth , moons around a planet, planets around the sun, or stars around other stars, do so because the momentum of their forward velocity is balanced by the gravitational pull of the parent object.

Basically the Earth is bowling along at nearly 20 miles per second, trying to go in a straight line that would take it away from orbit, but the sun at the same time is trying to pull it in.  The two forces balance.

If you could stop a satellite in it’s tracks, it would fall to Earth – simple as that.  

When an atronaut is orbiting the Earth, all he has to do to re-enter the atmosphere is to fire the retro rockets to slow down, and the capsule loses some forward momentum, the Earth’s gravity takes over and the capsule begins to spiral into the atmosphere.