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)

  • $\begingroup$ Bodies do not rotate in circular orbits as even the smallest disturbance will result result in an elliptical orbit. You can think of the circle as a very special type of ellipse with box axes exactly the same size. $\endgroup$ – Farcher Feb 8 '17 at 16:13
  • $\begingroup$ Re, "...gravitation makes a body rotate..." That is not true. Gravitation attracts bodies directly toward one another. It is the interacting laws of gravity and inertia that allow (not cause) bodies to orbit one another. $\endgroup$ – Solomon Slow Feb 8 '17 at 16:34
  • $\begingroup$ But if a disturbance causes changes then the after sometime gravity will again make that to rotate in circular orbit like we rotate a stone by attaching it to a string but why the distance will vary ie somewher it is more and at some place less $\endgroup$ – Pranab Prakash Mishra Feb 8 '17 at 16:35
  • $\begingroup$ If we place a ball in a water tub and rotate then the ball makes near particles to come to it that is what called gravity then the particles ultimately attach to the ball but what if the particles has some rotation on their own causing centrifugal force outward then they will start to rotate this is gravity which comes into act due to rotational motion of a body as einstein said $\endgroup$ – Pranab Prakash Mishra Feb 8 '17 at 16:43
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    $\begingroup$ No, this is complete nonsense, and Einstein most certainly has never said anything of that sort. The experiment you quote has nothing to do with gravitational attraction. And, no, it is not the case that "gravitation makes a body rotate in circle". $\endgroup$ – Pirx Feb 8 '17 at 17:52

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.

conic sections

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.

  • $\begingroup$ Cant understand $\endgroup$ – Pranab Prakash Mishra Feb 8 '17 at 16:48
  • $\begingroup$ did you look at the link? $\endgroup$ – anna v Feb 8 '17 at 17:31
  • $\begingroup$ i have edited extensively $\endgroup$ – anna v Feb 8 '17 at 17:48
  • $\begingroup$ Madam anna me would be happy if u would tell me that why (not mathematically)but from physical point of view if i have thrown a particle away i meant it starts rotating on basis of gravitation then how can it go farther distance at sometime and come nearer at other and that dont happen when moon revolves around earth $\endgroup$ – Pranab Prakash Mishra Feb 8 '17 at 19:37
  • $\begingroup$ because the earth is sitting in one of the focuses of the elipse. It does happen with the moon ifa.hawaii.edu/~barnes/ASTR110L_S03/lunarorbit.html . Maybe this about satellites will help you physicsclassroom.com/mmedia/vectors/sat.cfm $\endgroup$ – anna v Feb 9 '17 at 8:14

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