When a satellite orbits the earth it is sometimes described as continuously falling toward the earth. How can that be?
A falling satellite?????
- Thread starter maverick2112
- Start date
Ok, I'll take a stab at this.
I was of the belief that satellites stayed in the same place relative to the earth, and at a constant altitude because it's inertia (generated from launch) is exactly equal to the pull of gravity on it. In essence it is constantly and simultaneously "falling to the earth" and being thrown away from the earth (centrifugal force).
However, it is possible that it IS always falling VERY VERY slightly towards earth. Eventually all satellites fall to earth. I don't know the exact physics of it, but perhaps the force of gravity is microscopically greater than the force of outward inertia on it. Perhaps in the first few years it may only "fall" a few inches or feet away from the point of perfect equilibrium. But over the course of 15 to 20 years it's rate of descent will have gradually accelerated, until it gets to where the gravity is just too strong, at which point it comes screaming down towards earth.
I was of the belief that satellites stayed in the same place relative to the earth, and at a constant altitude because it's inertia (generated from launch) is exactly equal to the pull of gravity on it. In essence it is constantly and simultaneously "falling to the earth" and being thrown away from the earth (centrifugal force).
However, it is possible that it IS always falling VERY VERY slightly towards earth. Eventually all satellites fall to earth. I don't know the exact physics of it, but perhaps the force of gravity is microscopically greater than the force of outward inertia on it. Perhaps in the first few years it may only "fall" a few inches or feet away from the point of perfect equilibrium. But over the course of 15 to 20 years it's rate of descent will have gradually accelerated, until it gets to where the gravity is just too strong, at which point it comes screaming down towards earth.
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How Do Satellites Stay in Orbit?
How Do Satellites Stay in Orbit?
TELL ME WHY
by Arkady Leokum
According to Newton's law of motion, a rocket shot into the air should continue in "uniform motion in a straight line" unless forced to change by some external force. That force is the Earth's gravity, which pulls all things toward the center of the Earth. So instead of flying off into space in a straight line, the rocket is pulled down toward the center of the Earth. So gravity is pulling constantly on the rocket. The Earth, however, is curved. So as the rocket falls, the Earth curves way from it. If the rocket is traveling at a speed of 17,000 miles an hour (or 4.7 miles a second) its falling toward the Earth will be balanced by the curving away of the Earth's surface. In this way, even though it keeps falling, it will keep going around the Earth in orbit. But something else comes into play -- friction. Since the rocket has not gone high enough to escape the atmosphere around the Earth, the force of friction will slow down the rocket and thus change that "balance." As a result, the rocket will finally fall back to Earth. If a rocket does escape the Earth's atmosphere and from the pull of the Earth's gravity, it then comes under the pull of the sun's gravity and it goes into orbit around the sun.
UNIVERSAL PRESS SYNDICATE
THURSDAY, MARCH 26, 1998
COPYRIGHT 1998 UNIVERSAL PRESS SYNDICATE 4520 Main St., Kansas City, Mo. 64111; (816) 932-6600
How Do Satellites Stay in Orbit?
TELL ME WHY
by Arkady Leokum
According to Newton's law of motion, a rocket shot into the air should continue in "uniform motion in a straight line" unless forced to change by some external force. That force is the Earth's gravity, which pulls all things toward the center of the Earth. So instead of flying off into space in a straight line, the rocket is pulled down toward the center of the Earth. So gravity is pulling constantly on the rocket. The Earth, however, is curved. So as the rocket falls, the Earth curves way from it. If the rocket is traveling at a speed of 17,000 miles an hour (or 4.7 miles a second) its falling toward the Earth will be balanced by the curving away of the Earth's surface. In this way, even though it keeps falling, it will keep going around the Earth in orbit. But something else comes into play -- friction. Since the rocket has not gone high enough to escape the atmosphere around the Earth, the force of friction will slow down the rocket and thus change that "balance." As a result, the rocket will finally fall back to Earth. If a rocket does escape the Earth's atmosphere and from the pull of the Earth's gravity, it then comes under the pull of the sun's gravity and it goes into orbit around the sun.
UNIVERSAL PRESS SYNDICATE
THURSDAY, MARCH 26, 1998
COPYRIGHT 1998 UNIVERSAL PRESS SYNDICATE 4520 Main St., Kansas City, Mo. 64111; (816) 932-6600
