Why hasn't the earth crashed in to the sun yet?
If we drop a ball out of a plane it reaches its terminal velocity and then accelerates no more. This is due to resistance from air. In space there is no air to offer resistance to the path of the earth so why hasn't the gravity pull of the sun caused the earth to be continually accelerating towards it at phenomenal speeds and already crashed into it by now?
matt_london1 Sat 10/05/08 09:13
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Because the gravitational pull of the Sun is balanced by the orbital velocity of the Earth.
It's like spinning a weight rouynd on the end of a piece of string. So long as you keep the rotational speed up the weight does not crash into your hand.
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why doesn't the heat of the sun burn the string at its end?
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The string is heat-proof as it is made of (perhaps) gravitons.
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wouldn't a (heat proof) piece of elastic be a better analogy
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wouldn't the string get tangled up with the string from other planets?
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Check out the physics websites for 'string theory'. The reason the other planets stay safe is called 'quantum entanglement'. Jake will be here any minute.
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According to Einstein's theory, any mass warps space around it. Imagine a heavy lead ball placed on a thin sheet, the surface of the sheet will sagl and the ball will sink into the depression. The ball represents the mass, and the bed represents space.
Therefore, the planets, relative to themselves, are actually following a straight line. But since the sun warps space around it, the planets appear to follow a circular path around the sun.
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Anyways, according to Newtonian physics
This happens because the Earth has a velocity in the direction perpendicular to the force of the Sun's pull. If the Sun weren't there, the Earth would travel in a straight line. But the gravity of the Sun alters its course, causing it to travel around the Sun.
The earth continues falls towards the sun at every point in its orbit but never hits it thus following an elliptical orbit with the sun at its focii.
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Thnaks Knobby for my first smile today.
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Earth falls towards the Sun annually but as it falls it gains velocity by the conservation of angular momentum (the figure skater spinning faster as they pull their combined mass inward). The velocity gained in falling towards the Sun increases the Earth's orbital velocity which then forces it further away from the Sun slowing its orbital velocity again allowing gravity to pull it back. These mutual changes in distance and velocity are sufficiently balanced to produce a stable orbit of the Earth around the Sun.
The Sun over time is losing mass through radiation and this has actually increased the distance at which the Earth orbits the Sun (slightly).
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I used the word "fall" not as in lessening of orbital distance, but
as the object moves tangentially, it falls toward the central body. However, it has enough tangential velocity to miss the orbited object, and will continue "falling" indefinitely.
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sorry mibwnc but it's obvious that the earth does not have skates so how would that work then? Am I the only person that sees these things?
Matter tells space how to bend, space tells matter how to move.
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