StarDestroyer.Net BBS

A science type question for all the knowledgeable folks.

With all the steel, concrete and other building materials used in creating Coruscant, (miles of vertical buildings in some places, yes?) I am assuming not all of it is from the planet itself, would the mass added over the course of the planets life have any effect on it's gravity for it's inhabitants, gravitational pull, orbit or the orbit of it's moons?

Even assuming the entire surface is covered in a solid block of iron 4 km thick (a gross overestimate) it adds only 3.1*10^22 kgs to the total mass, which was already 1.637*10^25 kgs. From Newton's second law F=m*a, so F=m2*g. From Newton's first law F=G(m1*m2/r^2) so F=(G(m1/r^2))*m2
Substitute and rearrange for g=G(m1/r^2).
g=6.67*10^-11(1.64*10^25/(8.854*10^6)^2) = 13.95 m/s^2, compared to the initial gravitational acceleration of 13.93 m/s^2.

So it is negligible on any kind of observable time frame.

Cool. Thanks.

Not to mention, I wouldn't be surprised if in-situ construction and fabrication technology isn't so sophisticated they couldn't have subsurface bores extracting material, refining it, and fabricating it into usable structures and inhabitable honeycomb, with a minority of imported material.

Basically what Ender said, it amounts to at most an extra few km of crust (and crust honeycombed with air spaces at that), so the mass should be negligable compared to the mass of the planet.

Also, unless they're building with real exotic materials I doubt most of it would be imported. Even with Wars hyperdrive importing the equivalent of concrete and steel from other planets strikes me as much less economical than simply having a bunch of quarries and mines on the planet.