Take the 2-minute tour ×
Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. It's 100% free, no registration required.

I was looking at Wikipedia's Solar system page, and it says that Sun represents 99.86% of the whole solar system mass. I found that pretty huge.

So i calculated ratio of masses : Earth / (Earth + Moon) and it's about 98.78%.

I did the same with Jupiter : Jupiter / (Jupiter + Io + Europa + Ganymede + Callisto) and it's about 99.97% (I ignored small satellites).

  • Why is it such a high ratio in this 3 examples?
  • Is 1% a regular number for satellites' mass?
  • It is simple gravitation maths ?

I understand that one body has to be much more massive in order to be a planet-satellite system, otherwise it's a double planet system. But I would have thought 90% would be enough.

share|improve this question
add comment

1 Answer

No, there is no pattern on 1%. There are cases of double stars and (allegedly) of double planets.

In our Solar System, Charon has a mass of 11.6% of that of Pluto.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.