As we know that gravitation makes a body rotate in circle So sun should also make earth rotate in circular orbit But why earth rotates in elliptical We not think that it is to cover equal areas in equal time My question is why it became elliptical at first defying gravitational law (at formation of orbit)
My question is why it became elliptical at first defying gravitational law(at formationof orbit)
The gravitational law is more general than you think, not a circle but an ellipse is the more general stable orbit solution.
In general the solution of the orbits of two bodies in the gravitational well of each other are conic sections
One application is that a moving particle that is subjected to an inverse square law force like gravity or Coulomb's law will follow a path described by one of the conic sections.
parabolas, hyperbolas, ellipses ( of which limiting cases are circles and lines)
One of the two bodies is sitting at a focus of the ellipse (an ellipse becomes circle when the two foci fall on each other) . Parabolas and hyperbolas are scatteringsaround a focus leaving off to infinity. In a line ( the limit when the two ellipse foci are very far from each other) one object falls on the other.
The "why"s answered by " because when the disk that coalesced into the mass that became the earth was formed it happened that the sun was close to one of the two ellipse foci."
The formation of the Solar System began 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud.Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and other small solar system bodies formed.