How does a geostationary satellite remain over the same spot on Earth?
In: Planetary Science
for a fighter jet to fly a loop, it uses movement of the wings along with thrust from the jet engine to push against the air around it and fly the loop.
but the international space station(ISS) doesn’t have wings or thrust or air to push against. so, how does *it* fly in a giant loop? the answer is gravity.
gravity doesn’t stop at the edge of our atmosphere. so, even though the ISS is in space, the earth is pulling it the entire time. but because of how gravity works, it can only pull at a certain speed. the ISS was let loose at such a speed sideways to earth that by the time the ISS has fallen to where it would meet the surface of the earth, the ISS is really far to the side from where it would have landed.
and since the earth is round, the distance the ISS has fallen can actually curve *with* the earth so perfectly that the ISS is still the same distance from the surface and is now over a totally different area of the earth’s surface.
the ISS is roughly 250 miles above the earth’s surface, and it has to move sideways so fast to avoid falling into earth that it makes a full loop all the way around the earth about every 90 minutes.
because of how gravity works, the farther from the earth something is, the weaker the gravity, and the slower that object will fall to earth. as you go farther away from earth, the time it would take to complete a full loop around the planet reduces. far enough away at some point, it will take 100 minutes to complete a loop, at a farther distance it will take 120 minutes. and if you keep going, you will find a distance that will let you take 1460 minutes, or 24 hours, to complete a full loop.
what else take 24 hours? a day! and what is a day? it’s what we call a complete spin of the earth!
so, if the earth’s surface takes 24 hours to complete a spin and an object in space takes 24 hours to complete a loop, then that object is staying in motion above the same area of the earth’s surface. the surface and the object are “in sync”
Latest Answers