Satellites- like Galileo gps navigation satellites - orbit earth explain how gravity makes this happen?

Answer 1

Here is an answer that might seem childish or facetious at first, but I've had some good luck

getting the idea across with this explanation, and I urge you to try it out.

You have several baseballs, and you're going to exercise your pitching power. One at a time,

you'll take each Baseball, throw it perfectly horizontally, and see how far it goes before it hits

the ground.

You toss the first ball easily, and it hits the ground a few meters in front of you.

You toss the next one with more speed, and it goes a few meters farther than the first one went.

You toss the next one with even more speed, and it goes even farther before it hits the ground.

The faster the ball leaves your hand, the farther it goes before it meets the surface. Gravity takes

some time to pull it down, and the faster it goes horizontally, the farther it can go during that time.

Now, remember that the earth isn't flat. It's a sphere. If you start out horizontally and keep going

in a straight line, the sphere (earth) curves down and away from you.

Same is true for the baseball ... You throw it horizontally. As it flies away from you, gravity pulls it

down, always toward the center of the earth. But because the earth is a sphere, the earth's surface

also curves down from level, as the level gets farther from you.

If you throw the baseball fast enough, the earth curves down and away from it just as fast as gravity

pulls it toward the center of the earth. So it keeps falling, but the surface falls away just as fast ! The

baseball never falls fast enough to hit the ground, because gravity doesn't pull it down hard enough.

It just keeps falling all the way around the earth, never catching the ground.

If the ball it has to plow through the air, then it loses its sideways speed, and eventually it does fall

to the ground. That's why there are no artificial satellites that just barely skim the ground ... they

have to stay out of the atmosphere, or else they'll run out of steam. But on the moon, where there's

no air to slow down an artificial satellite, it can stay in an orbit that's just high enough to clear the

mountain tops.

Answer 2

Gravity is the force that attracts objects with mass towards each other. Satellites like the Galileo GPS navigation satellites orbit Earth because they are in a state of free fall towards the planet, balanced by their tangential velocity. This delicate balance between the satellite's forward motion and Earth's gravitational pull allows the satellite to continuously fall around Earth in a stable orbit.