Rushing all the time, Falling all the time

Everything in the sky is moving, and, at the same time, everything in the sky is falling. These two - inertial motion and the falling due to gravity - are in a delicate balance. And this balance is what keeps them in their paths.

The Moon, hovering over the Earth, is being slightly tugged by it, about fifteen feet every hour. This tug is the result of the Earthıs gravity. If that were the end of the story, the Moon would quickly fall down on our heads. But the Moon is also rushing around the Earth at two thousand miles an hour. Again, if that were all that was happening, the Moon would soon be lost to sight, receding from the Earth at - fifteen feet an hour.

And so, there is a balance. The straight line motion - the motion we all experience when we try to turn on glare ice, the motion we call inertia - is exactly balanced by the gravity of the Earth.

The Earth orbits the Sun at over sixty thousand miles an hour. The Sun travels around the center of the galaxy at over a half a million miles an hour.

All this motion is to escape the demon gravity. For without these motions, not only would the Moon fall to the Earth, but the Earth itself would fall into the Sun, and the Sun would fall to the center of the galaxy. Every stable orbit is a compromise between the inexorable force of gravity and inertia, the tendency any object has to keep going as it is at that instant.

Our motion around the Sun has kept us at a safe distance. We canıt stop, not even for a moment. We have to keep moving or we die.

(04/25/07)