Why is Kepler's first law valid? Why do the known planets orbit in a ellipse around the sun, with the sun as one of the foci? WILL GIVE MEDAL! PLZ HELP

Question

davidusa · Answer

@amematsro help

anonymous · Answer

The reason that the orbit of a planet is an ellipse is because of the added gravity of the other massive planets like Jupiter, so if there was only one planet the orbit would be a perfect circle

davidusa · Answer

Thanks for responding, but why does it make it an ellipse? I understand now why its not a perfect circle, but why an ellipse with the sun as one of the foci? if the other planets are pulling each other, shouldn't the orbits be more random then a specific ellipse?

anonymous · Answer

the eclipse is the only stable orbit it can have, a circle is just a special type of ellipse, does that answer your question

anonymous · Answer

ellipse not eclipse

davidusa · Answer

Kind of, thank you, but I still don't understand... :( Do you have a picture or graph you can show that h|dw:1406853126952:dw|

davidusa · Answer

that can help explain, oops forgot to finish lel

anonymous · Answer

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the reason it's not random is because the gravitational pull of the sun is much larger than that of the other planets, s
better?

davidusa · Answer

Very good answer, I kind of understand now. One last thing. Why is the sun always one of the foci of the ellipse? How did Kepler know that?

anonymous · Answer

Kepler just kind of guessed, he mapped the positions of the planets over a few years

davidusa · Answer

Oh ok thanks.

davidusa · Answer

|dw:1406853800521:dw|why doesn the orbit keep changing? even though the sun's gravity is much more than the other planets, shouldnt the planets keep pulling and pushing each other out of the orbit? shouldnt the orbit be changing like above?

davidusa · Answer

Yay thank you  :)

anonymous · Answer

Yeah it should but the affects from the other planets are so slight, that we won't be able to notice a difference for almost a millions years