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## Elliptical Orbits

1. Why do planets move in elliptical paths and not in circular ones?

Ellipse is a more general shape than a circle. Circle is a special case of ellipse when its semimajor axis and the semiminor axis are of equal lengths.

The shape of orbit depends on various factors.

Johannes Kepler in the 1600s was the first to start discussing the shape of planetary orbits, formulating a series of laws to explain their shape and characteristics. Isaac Newton and Albert Einstein contributed additional research and theories.

Shape of a planet’s orbit is affected by the gravitational force of sun as well as other planets.

Also Remember that the sun is also in motion, which makes elliptical orbit an easy one than a perfectly circular one.

## why earth moves in an elliptical orbit instead of circular one?

why earth moves in an elliptical orbit instead of circular one?

Ans:

Please note that ELLIPSE is the more general form for an orbit and CIRCLE is a speacial case of ellipse.

So, it is more general way of saying that the orbits are elliptical. If it were circular, we would have more trouble explaining why they are perfect circles.

The situation where the Sun, for instance, would be exactly in the center of a perfectly circular planetary orbit couldn’t happen in our Solar System since there are other planets that would gravitationally affect the orbit and cause it to be immediately non-circular by pulling the object to one side or the other.  Any other stable orbit type than a perfectly circular one turns out to be an elliptical orbit.

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