2006-09-23 04:30:06 · 5 answers · asked by goring 6 in Science & Mathematics ➔ Astronomy & Space
There's no such thing as an inertia force that makes things move in a straight line. Things travel in a straight line precisely because there is NO net force on it.
Anyways, to answer your question. Earth and most objects have elliptical orbits because to get a circular orbit you'd need a very precise speed and direction. Even if the Earth orbited in a circle at some time in the past, any slight change in it's speed would make it an ellilpse. A change in speed or direction could be caused by gravitational interactions with the other planets or even objects hitting it.
2006-09-23 05:45:48 · answer #1 · answered by Demiurge42 7 · 0⤊ 0⤋
Two physical laws explain the elliptical orbits of the planets. The first is Newton's law of universal gravitation, also known as the inverse square law: the Sun and the Earth attract each other with a force that is proportional to the mass of each and inversely proportional to the square of the distance between them. The second is the fact that an object responds to a force by accelerating in the direction of the force by an amount that is inversely proportional to the mass of the object (I am quoting here from "The Character of Physical Law" by Richard Feynman).
Everything else is just math. With a little calculus you can prove that the two physical laws above will cause the Earth to follow an elliptical path.
2006-09-23 08:47:39 · answer #2 · answered by Jack D 2 · 0⤊ 1⤋
The earth and the sunlight are attracted to a minimum of one yet another, the earth has momentum in an opposing direction. The elliptical orbit is a sum of those forces, besides simply by fact the less influential appealing gravitational forces from all different vast bodies exterior the earth. we are left to presume the earth has momentum from some preliminary accelerating rigidity, and this may well be augmented via rotational forces.
2016-12-15 12:57:33 · answer #3 · answered by Anonymous · 0⤊ 0⤋
In order to have a circular orbit it should have more speed and at higher distance from the sun.
To orbit in circular orbit the centrifugal fore should be equal to the gravity. Which is unique. Where as the elliptic orbit adjust itself by accelerating and decelerating. Therefore even if one starts with circular will end up in elliptical orbit when millions or billions of years pass by due to slight deviations.
2006-09-23 06:23:13 · answer #4 · answered by Dr M 5 · 1⤊ 1⤋
It is a mix between inertia, which is the force that makes things movie in a straight line, and gravity, which makes earth go slightly towards the sun. when they are both affecting the earth, it moves in a elliptical orbit.
2006-09-23 04:32:48 · answer #5 · answered by Anonymous · 1⤊ 1⤋