eli5: I’ve heard orbit described as continuously falling past or missing the Earth, how then do objects in geosynchronous orbit above a single point not fall out of the sky?
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The key to understanding geosynchronous orbit is that it’s no different than any other orbit. It’s just an object orbiting a massive body like any other. All the same rules apply.
One of those rules is that the closer you are to a massive object, the faster you have to go to stay in orbit. The further you are the slower you have to go to avoid shooting off. So the orbital speed is directly related to the distance from whatever you’re orbiting. In other words, the higher the altitude, the slower the orbital speed.
Last piece: the earth is spinning at a certain speed. This doesn’t impact orbital issues at all. But if a satellite’s orbital speed happens to be the same speed that the earth is be spinning, well happy coincidence: it’ll *appear* to be stationary from the ground. But it’s not, it’s just that you and the satellite are going around the earth’s center at the same speed.
The earth is turning one rotation per day. At geosynchronous orbit it takes one day to fall around the earth
The earth is turning one rotation per day. At geosynchronous orbit it takes one day to fall around the earth
The earth is turning one rotation per day. At geosynchronous orbit it takes one day to fall around the earth
At a specific height, the speed you need to miss the earth while falling is the same as how fast the earth rotates.
At a specific height, the speed you need to miss the earth while falling is the same as how fast the earth rotates.
At a specific height, the speed you need to miss the earth while falling is the same as how fast the earth rotates.
Geosynchronous satellites go very fast – about 3 km per second. However, they are also very far away from the Earth: about 36,000 km, which means (taking into account the Earth’s radius of 6,400 km) their orbit is a giant circle about 265,000 km in circumference.
That’s a really big circle. Even zooming along at 3 km a second, it takes 86,400 seconds to make it all the way around – that is 24 hours, or one day. That means by the time they make it all the way around, the Earth has also spun all the way around, and they are over the exact same point on the Earth where they started. In fact, they remained over that point the whole time, because the Earth rotated underneath them as they zoomed around the big circle.
Geosynchronous satellites go very fast – about 3 km per second. However, they are also very far away from the Earth: about 36,000 km, which means (taking into account the Earth’s radius of 6,400 km) their orbit is a giant circle about 265,000 km in circumference.
That’s a really big circle. Even zooming along at 3 km a second, it takes 86,400 seconds to make it all the way around – that is 24 hours, or one day. That means by the time they make it all the way around, the Earth has also spun all the way around, and they are over the exact same point on the Earth where they started. In fact, they remained over that point the whole time, because the Earth rotated underneath them as they zoomed around the big circle.
Geosynchronous satellites go very fast – about 3 km per second. However, they are also very far away from the Earth: about 36,000 km, which means (taking into account the Earth’s radius of 6,400 km) their orbit is a giant circle about 265,000 km in circumference.
That’s a really big circle. Even zooming along at 3 km a second, it takes 86,400 seconds to make it all the way around – that is 24 hours, or one day. That means by the time they make it all the way around, the Earth has also spun all the way around, and they are over the exact same point on the Earth where they started. In fact, they remained over that point the whole time, because the Earth rotated underneath them as they zoomed around the big circle.
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