How large would the sun appear to be from the other planets?

On Fri, 13 Oct 2000, you wrote:

> I've searched and searched and can't find the answer to this question:
>
> What is the relative size of the sun in the sky from the various outer
> planets?
>
> I know how big it looks in the sky from earth, but what size would be it
> from the surface of Mars, or from orbit around Jupiter and Saturn?
>
> Is there a way to figure this out?

Luckily, there is a fairly simple way of figuring this out. Once an
object's angular size is small enough (say, under 10 degrees), as you move
further away, angular size scales inversely with distance. On the Earth,
the sun subtends about 1/2 degrees. From a vantage point twice as far
away, the sun would appear half the size, or 1/4 degree.

The distance from the Earth to the sun is called an "astronomical unit" (1
AU), and the distances from the Sun to each planet is usually in AU (e.g.
Venus is at a distance of 0.7 AU form the Sun). So, just take the
semi-major axis of each planet's orbit in AU, and the size of the sun in
degrees is 0.5 / distance.

If you need distances from each planet to the sun, check out the SEDS
Solar System link on our webpage

Thanks for writing!

Sincerely,
Kurtis Williams

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