earth is said to use an elliptical orbit while orbittin around the sun..then y is sun at the focus?

Question

why is sun at the focus of the imaginary ellipse..why nt the center or any other place in the imaginary ellipse?

Answer 1

It would take pages to do the math, so I'll try to do it descriptively. The foci of an ellipse can be any distance apart. If the distance is zero, both foci are at the same point, the center of a circle, the circle being a special case of the ellipse.

Now starting from an ideal circular orbit with the sun at the center, you perturb the orbit of Earth a bit. Not only do you knock the Earth into an elliptical orbit, but you knock it off-center.

Answer 2

A good question. I used to be a high school science teacher. In a second year university lecture, our physics professor once asked us what would happen if jesus magically placed a mass equal to the Sun at the empty focus. Nobody in the room, including him, knew the answer. But one of my 10th grade maths students, years later, replied when I asked the same question, that the orbit would become a circle, the diameter the same as the major axis of the present ellipse, with the two foci equidistant on either side of the centre. This answer is almost certainly right, just from symmetry considerations, even though I can't prove it rigorously. An elliptical planetary orbit is a bit like a pendulum swinging in an ellipse. Start the pendulum swinging in a plane (flat) swing. Then give it a sideways nudge and it will start to swing in an ellipse. It takes a special set of conditions for a planet or pendulum to move in a perfect circle. More likely the conditions that started its motion will produce an ellipse.

Answer 3

the earth-sun system has a center of mass which lies
about 449 km from the center of the sun.


citing wikipedia:

"The barycenter (or barycentre; from the Greek βαρύκεντρον) is the point between two objects where they balance each other. In other words, the center of gravity where two or more celestial bodies orbit each other. When a moon orbits a planet, or a planet orbits a star, both bodies are actually orbiting around a point which lies outside the center of the greater body. For example, the moon does not orbit the exact center of the earth, instead orbiting a point outside the earth's center where their respective masses balance each other. The barycenter is one of the foci of the elliptical orbit of each body. This is an important concept in the fields of astronomy, astrophysics, and the like (see two-body problem)."

Answer 4

The ellipse is not imaginary and the sun is at its center because of its gravity. Easy huh?

Face it you are a space traveler around the sun. Even God likes that.

Yours truly'
Jonnie

Answer 5

first of all, the solar isn't on the middle of the ellipse. it is at a concentration. this means that there is one closest element and one farthest element for the earth and the solar, not 2 each. 2d, the seasons are actually not desperate by using ways close we are to the solar. whilst it is iciness interior the Northern Hemisphere, it is summer season interior the Southern Hemisphere and vice versa. The seasons are actually desperate by using ways lots photograph voltaic falls on each little bit of area. because of the lean of the earth, it fairly is greater at some cases than at others. whilst the solar is closer to being overhead, it is summer season whilst it is decrease interior the sky all day, it is iciness. It seems that the earth is farther removed from the solar interior the Northern summer season than it is in the process the Northern iciness.

Answer 6

Newton used Euclidean geometry to prove that an object in orbit has to follow an elliptical path. Richard Feynman used to start his courses with a similar, but not identical proof.

If you get the book "Feynman's Lost Lecture" you will find both Newton's and Feynman's proofs there. They are understandable to anyone who has done basic geometry.

Answer 7

sun is at the focus as the thoery goes, the planets were spurn out of the sun, so once they got ejected the gravity of sun compelled them to orbit around it, as the moon was a part of the earth, so it revolves around the earth

Answer 8

The sun is at a focus, there are two. It is a natural consequence of Newtonian mechanics, as you will learn in college physics.

Answer 9

It's just how the equations of gravity and motion work out. Kepler observed it and Newton derived it from first principles.

So the short answer is 'it's the physics'. The long answer is much longer.

Answer 10

An ellipse has two focal points.
The Sun is at one focal point.