http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html
> The Moon is about 2% of Earth's mass, not 27%.
2% of mass, yes, but also 27% of the diameter.
You are both right.
Then 0.27^3 = 0.0197
And then, only 60% as dense (no core) so 0.0119 :)
And only just barely! You get to around 99% of the Earth's mass with the rest of the inner solar system.
All of the other rocky bodies in the solar system give you another 10% of Earth's mass out to Pluto and another 10% beyond.
Is that correct? Venus alone is about 90% the size of Earth, and Mars roughly 33%. It really seems like all those bodies put together should be greater than 1 Earth mass (but less than 2 Earth masses).
Venus is about 81% Earth's mass, and Mars is only a little over 10%. Mercury gets you another 5.5%, the Moon (as above) another 1.2%, and the asteroids are negligible.
In the outer solar system, it's basically all the Galilean Moons + Titan.
ETA: Hmm, or maybe those are surface gravity numbers you're thinking of?
I do find it really interesting and a little mind-boggling that the Moon, as huge as it is, with a good 1/6 of Earth's gravity, only has 1.2% of Earth's mass. Same with Mars: a good 1/3 of Earth's gravity, but a mere 10% of its mass. I really thought there'd be more direct correlation between mass and gravity than that. Of course, surface gravity is related to mass with both density and radius, but still, I would have assumed that the densities of these bodies would have been rather similar, as they're all small, rocky worlds.
Consequently, the mass of an object with a given surface gravity is inversely proportional to the square of the density. If the Moon were the same density as the Earth, and had the same surface gravity as it does now, it'd actually mass less than it does now -- and Uranus, despite have 15x the mass of Earth, has a lower surface gravity, because its density is so low.
The rule of thumb for space is "any way your intuition can be wrong, it will be wrong". :-)
What do we know about the gas giants' cores?
Due to the intense conditions inside a gas giant, we're not sure if they still have a rocky core, or if the cores have liquified or even convected away to mix with the gasses.
So the answer could be "there are dozens of times the Earth's mass worth of rocky material inside gas giants" or "there is no rocky material inside gas giants", or anywhere in-between. We need more detailed study of the gas giants before we can answer that question.
Models of solar system formation also suggest the Kuiper belt started with dozens of times Earth's mass, but we only see about 10% there now, and we only have pretty good guesses about what happened. (I mean, it almost certainly got ejected, but the "why" is harder.)
https://en.wikipedia.org/wiki/Juno_(spacecraft)#Scientific_o...