Is the moon's orbit around the sun absolutely straight?

Answer 1

Yes, the moon's orbit is elliptical. It has some eccentricity to it (e = 0.0549). The measure of eccentricity is done to give astronomers an idea of how "out of round" a body's orbit about a center is, and it can vary between e = 0 for a perfect circle (no eccentricity), on out to e = 1 for the longest, skinniest ellipse you can immagine (infinite eccentricity).

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Further to that correct answer, when the eccentricity is small, as it is for the planets (except Mercury), the orbit is very nearly circular, and the eccentricity measures how far off-centre the Sun is.

For example the Earth's orbit has an eccentricity of 1/60 and a radius of 150 million kilometres. The Sun is offset from the centre by 150/60 million km, or 2.5 million km.

The maximum diameter of the elliptical orbit is 300 million km, while the minimum diameter is 299.96 million km, so there is virtually no 'squashing' of its circular shape.

Answer 2

The Moon's orbit is elliptical (oval) and varies from circular by about 10%. Its perigee is about 362,000 kilometers and the apogee about 405,000 kilometers.

Answer 3

The moon orbits the earth, not the sun.

If you did draw the path the moon actually follows around the sun it would look very much like a pattern drawn with a SpiroGraph Toy!

Answer 4

No