Why a Baseball Could Orbit
Suppose you were standing on an extremely high mountaintop on Earth, and you fired a bullet horizontally. The bullet would travel in an arc, curving downward as it speeds away from the mountain and eventually hitting the ground, pulled by gravity.
A relatively slow bullet would hit the ground near the mountain. Faster bullets would travel farther. If it were fast enough, a bullet could end up going entirely around Earth. Like a tiny moon or a satellite, it would travel around in its circular orbit again and again. (Be sure to duck before it circles the globe and comes back to you from behind.)
A bullet shot horizontally from a mountaintop will eventually hit the ground, unless its initial speed is fast enough to put it in orbit.
Using the laws of motion formulated by the English scientist Isaac Newton more than three hundred years ago, it's possible to calculate the necessary speed for an object, such as a bullet or a spacecraft, to go into orbit around Earth or any other spherical body.
The launch speed (escape velocity) depends on the object's distance from the sphere's center and the acceleration caused by gravity. A satellite orbiting just above Earth's surface would have to travel at a speed of about 11.2 kilometers per second to remain in orbit.
A softly thrown baseball moves at about 10 meters per second. A hard-hit baseball can go 40 meters per second or faster. That's fast enough for a ball to go into orbit around a small asteroid!
NEXT: The Bumpy Bike Path
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