PC Satellite Tv Box
Posted on Jul 29, 2010 under Forex Trading Software |PC Satellite Tv Box - Satellite Tv Software. Watch your favourite Movies, Tv shows, News and Sports anytime you want! Very Unique, High Converting Offer!
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July 29th, 2010 at 7:11 am
satellite?
why must the centre of satellite orbit coincide with the centre of the earth?
pls provide detailed answers
much appreciate <3
July 29th, 2010 at 12:13 pm
Because the Satellite is working against a force (gravity), whose force is centered within the heavy metallic core of the Earth.
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July 29th, 2010 at 12:15 pm
Actually that’s not true.
It is true if the orbit is circular.
But a satellite can have an elliptical orbit, in which case, the earth would be at one of the foci (focuses) of the ellipse.
Look at (search for) both Kepler’s Laws and Newton’s Laws.
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Me - I teach this stuff
July 29th, 2010 at 12:17 pm
It doesn’t. Once I tried to place a satellite in a synchronous orbit ,But it wound not stay where we wanted it it stay. It turned out that gravity has mountains and Vallie’s simular to the mountain’s mass below. We had to eventually pick a gravity valley where it would stay for a very long time.
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July 29th, 2010 at 12:19 pm
Add angela’s and zabudhar’s answer together, and you have your explanation.
However, in the case of an artificial geosynchronous satellite, the circular argument is valid. Angela explains the more general case of all objects in orbit around a main body.
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July 29th, 2010 at 12:21 pm
It’s the "center of mass" of each object that is used to define an orbit.
For all intents and purposes, the center of mass of the Earth is the same as the center of the Earth.
The center of mass for the satellite doesn’t necessarily have to be in the middle of the satellite, but man-made satellites are so small in comparison to the Earth that we can ignore it.
Why is the center of mass so important? This is an over-simplification, but the center of mass is the balancing point for any rigid object or system. If an object is turning free in space, it’s as if it were balancing on an invisible support at that point.
Now on to another point…
If you want to get really technical, the satellite wouldn’t be orbiting exactly around the center of the Earth (we’re assuming a circular orbit here). When you look at the Earth and satellite as a single system, it’s center of mass is at a point between the two. The Earth/Satellite system pivots on this point. Because of the massiveness of the Earth, this pivot point is pretty darn close to the center of mass for the Earth, but it isn’t exactly.
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July 29th, 2010 at 12:23 pm
it doesnt
an orbitting system involves the sum of the two masses, and the center of the orbit of the two objects, is in the CENTER OF MASS of the combined two…
if a stellite is small the difference between the mass cernter of the earth and the mass center of the combined two is very small, but exists
lets say the moon-earth system has a bigger difference: "For example, the moon does not orbit the exact center of the earth, instead orbiting a point outside the earth’s center (but well below the surface of the Earth)" http://upload.wikimedia.org/wikipedia/commons/5/59/Orbit3.gif
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July 29th, 2010 at 12:25 pm
It doesn’t. Only if the orbit is circular.
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