Planets have elliptical orbits which means that in some point in its orbit, a planet is closer to the sun.?

Question

how is it true. give some infos. tnx.. its a great help.
put your sources. tnx.

Answer 1

This is true. An ellipse has two points of focus (called foci). The planet moves in an orbit resembling a slightly flattened circle. The center of this orbit is actually a point halfway between the two foci.
The sun is always at one of the two focal points. Therefore, at some point in its orbit, when the planet is on the same side of the ellipse as the focal point with the sun, it is closer to the sun that it is when it is on the other side of the ellipse (the one with the focus that does not have the sun)
The point at which the planet is closest to the sun is called "perihelion" and the point where the planet is farthest from the sun is called "aphelion".

Answer 2

I'm not sure why you say the Sun should only allow circular orbits. I guess that's what you meant. Newton showed that the general solution for a body moving in an inverse square gravitational field was an ellipse with one focus at the sun, if it was a closed orbit. The circular orbit is a special case when the velocity vector and direction are just right. But most solutions are ellipses. Open orbits are hyperbolas. The planets aren't exactly on a plane but they're very close to it. The plane is called the "ecliptic". Pluto was the farthest planet from the ecliptic, with an angle of 17 degrees. But now that Pluto is not considered a planet anymore, the honor goes to Mercury at 7 degrees. So that means all the rest of the planets are within a few degrees of the ecliptic.

Answer 3

Consider the sun as a point. Choose any point within an ellipse and you will find that you're not equidistant to all points of the ellipse.

Answer 4

false because the greater radius is aways from the sun in horizontal line to the radius of the sun and the smaller radius of the ellipse is the ones that are directed at the sun, threfore it is closer at the northward end the planet of the smaller radius but it still isn't as much as it could have been with the longer radius.

Answer 5

yep, half of pluto's orbit is closer than neptune at times, and sometimes it's so much further, it depends on teh time of year. And it also depends on the ellipse. Some are bigger and thinner than others.