Why do the planets revolve in elliptical orbits?

Answer 1

The following was here before I added the links (see the related links). This is nonsensical but imaginative. The only thing here that is clearly wrong is the reference to centrifugal force. Anyone who knows physics knows that, TTBOMK, centrifugal force is not known to exist, but gravity is a centripetal force:

Imagine yourself in a very huge pool with a centrifugal force spinning very fast that it throws you out at a distance before you're caught by the vortex, now that you're trapped there's a limit to how fast this energy can take you around the center of force, this is your terminal velocity .Draw an invisible line from yourself to the center, according to the universal law of gravitation every object in the universe attracts another object with a force proportional to the product of their mass with a speed proportional to the distance between their center. In relation, your body should not shift any degree from the plane unless you lost or gained an amount of weight. Let's assume you magically gained some heavy weight, now your velocity has been altered and transformed into a variable velocity. The gravitational wave current is to weak to hold extra mass in that regional plane, so now you are attracted to the center of force with an accelerated mass difference but the initial speed of the center force does not change and since your mass is not greater than the center mass in relation to your speed, you will be flung back out until the force weakens and the process will repeat.

Answer 2

A circle is a special case of an ellipse, whose eccentricity is zero. So a circular orbit is an elliptical orbit with zero eccentricity. So your question really is "why is the eccentricity not zero for all the orbits?" The answer to this lies in the laws that govern the "motion under the action of a central force." In other words, when a body is moving under the influence of a force that has a definite "source" or a point of origin. For planets, or any object for that matter, this force is the gravitational force. The solution of the possible trajectories includes the general conic sections - hyperbola, parabola, and the ellipse. Only the ellipse is a closed trajectory. All planets around the sun move in closed trajectories, with the central force at one of the focii of the ellipse. This is very close to the location of the sun. In reality, the planets move about the center of mass of the planets and the sun, called the barycenter. The barycenter is close to the sun center, but not quite located at it, since the sun is so massive compared to all the planets combined.

Answer 3

Answer:

There is no special requirement that planetary and lunar orbits must be non-circular. There is one lunar orbit in our solar system that is about as close to circular as you can get. Think of it this way. Absolutely every stable orbit in the universe is elliptical (at least if our physics applies everywhere). It happens that some of those ellipses have both loci occupying the same point in space (defining a circle). When you consider all the possibilities in all orbits (distances between loci) it is no surprise that so few orbits are 'circular'.

Answer: Planets revolve asymmetrically (non-circular) due to the gravitational interference of external bodies.

The force of gravity is related by F = G(m1 m2) / r2

m1 Mass of body 1, m2 = Mass of body 2, G = gravitational constant, r = radius distance from the center of mass1 to the center of mass2. Since the masses remain the same (revolution doesn't change mass) and the constant stays constant, only the force and the radius change.

If the radius changes, the force changes. Newton's 1st law applies - an object in motion stays in that motion unless acted upon by an outside influence - an external force. In general over long distances the only force at work is gravity, it's logical to assume the force changing the radius is gravity, QED another mass. If another body attracts the planet at an angle greater than 0, the pull from the 2nd body would give a net reduction in perceived force (vector math) on the planetary body and therefore the radius would change.

If you can measure the distances involved with enough precision, you will see a lot of wobbles in the revolution of the planets around the sun; the interaction of the planets themselves and the interaction of other bodies.

Answer 4

"Why" is a very tricky question ... more a matter of philosophy than any hard science. Technically, the answer I'll give you here is really not an answer to"why", but it'll show you that elliptical orbits are at least consistent: If you start with the simple formula that Newton wrote to describe the idea of gravity, and if you know some calculus, and if you spend some time massaging the gravity formula, you can show that if the formula is correct, then any small body moving in the neighborhood of a large body has to follow a path that's a conic section ... meaning either a closed path in the shape of an ellipse, or an open path in the shape of a hyperbola. The difference depends on how much energy the small body is carrying. If it has enough energy so that the large body can't capture it, then it swoops past the large body, its path gets bent but not closed by gravity, and then it swoops away again, on a path that's the shape of a hyperbola. If it doesn't have enough energy to avoid capture, then it settles into a closed path around the large body in the shape of an ellipse. One chance in a million ... if the energy is just exactly precisely the minimum amount required to avoid capture, then the path is a parabola. But that's such a precise case that it actually never happens. Also one chance in a million ... if the ellipse is just exactly preciselyone where the foci are at the same place and the eccentricity is exactly zero, then the ellipse is a circle. But that's such a precise case that it actually never happens.

Answer 5

The answer to this lies in the laws that govern the "motion under the action of a central force." In other words, when a body is moving under the influence of a force that has a definite "source" or a point of origin. For planets, or any object for that matter, this force is the gravitational force. The solution of the possible trajectories includes the general conic sections - hyperbola, parabola, and the ellipse. Only the ellipse is a closed trajectory. All planets around the sun move in closed trajectories, with the central force at one of the foci of the ellipse. This is very close to the location of the sun. In reality, the planets move about the center of mass of the planets and the sun, called the barycenter. The barycenter is close to the sun center, but not quite located at it, since the sun is so massive compared to all the planets combined.

Read more: Why_do_planets_have_a_elliptical_but_not_circular_orbits

Answer 6

It is the result of the behaviour of the gravity force from the Sun, which varies as the inverse square of the distance (i.e. twice the distance gives one quarter as much force). That was discovered by Newton.

Kepler discovered each planet moves in an ellipse with the Sun at one focus. Newton produced the law of gravity, also his laws of motion, plus differential calculus. With these mathematical theories he was able to show that an inverse-square force would produce exactly the orbits that Kepler had discovered the planets actually follow. So a 2000-year-old mystery was solved.

Answer 7

Planets are NOT elliptical in shape, they are basically spheres. However their spherical shape is distorted by the centrifugal forces resulting from their spin. This makes their equators fatter and their shape becomes that of an "Oblate Spheroid".

Perhaps you were thinking of the orbit of a planet, that is elliptical. If that is what you were asking about there are answers to this here on Wiki-answers.

Answer 8

because THEY DO