How heavy is Coruscant?

Still, we are talking about our own pathetic little asteroid belt. How many actual Star systems are there in the Star Wars galaxy? Thousands and Thousands. Assume 25% have asteroid belts, and include raw materials from rather uninhabitable planets that were simply strip mined for resources and you could add A LOT of mass to a planet.

Carnage

 

yeah, you could add alot of mass but that does not mean the orbit will be changed. You have to impart an impulse. Hit the planet really hard, throw off mass really fast, things like that. What does it matter if you can import mass from other solar systems? I just illustrated that within the confines of our own solar system we have enough iron to turn all our land area into a big building. Many Coruscant buildings are in the realm of 5 miles high, far less than what I pointed out with what we have available. So, if we removed the oceans and spread the material out further we could reduce the skyline from 15 miles to 5 miles and cover the entire planet and perhaps inport water from the Oort Cloud.

 

In regards with Coruscanting Earth, what's Coruscant's diameter for comparison? We're 12,756 klicks across.

 

1.39 earth's diameter. So Coruscant is 17,1736 km in diameter.

 

Coruscant is actually smaller, not larger, at 12,240 kilometers in diameter.

 

Still, adding weight LOTS of weight does the velocity that Coruscant would travel in orbit change? I can't remember my physics THAT well, but I believe Kenetic energy is E=1/2 MV^2 (granted this is linear). Let's say they DOUBLED the mass of the planet....I don't believe the kenetic energy could change....so the velocity would have to decrease. I'll look into this more out of geeky curiosity.

Carnage

 

How exactly could we make the world heavier by building stuff using material that was already here?

Of course, Coruscant is a different story completely. Most of the city that was built since interstellar colonization (although I dont know what % that would be) would have probably been built with material mined/synthesised offworld.

 

The only way to change the orbit of a planet is by either expelling mass from it in great quantities at high rates of velocity, or add mass to it rapidly via a rather abrupt impact. You can add all the mass you want in gradual fashion and a planet will just move right along its orbit.
Now, I guess I should not say "all you want", at some point the mass of a body of increasing mass would start to seriously effect other bodies in the solar system. Here in our solar system you'd have to add enough mass to the Earth so it would actually effect the orbits of Venus and Mars and to do that you'd have to start getting into masses equal to the outer planets. Doubling Coruscant's mass would not have any real effect if any at all.

If I'm wrong I'm not far off the mark, but if anyone really knows any better then I'd love to hear it.

 

Cities like New York, Bombay, Tokyo and Shanghai may sink because they are near the sea and have massive amounts of shifted material built on them - this pushes the entire area down if not carefull - Shanghai may sink due to over-building.

Coruscant dosent have this problem because for starters they have a level of thechnology that means the miles of skyscrapers are made of ultra-light materials, and reinforced by other advanced technologies - perhaps foundations that go deep into the crust. Most importantly - no oceans, so no soil subsiding.

Its all pretty simply stuff, but of course, Star Wars is an exagerated fantasy setting anyway, so unlike Star Trek or something, it isnt meant to be realistic - cities like Nar Shaddar that extend into orbit would not happen for economic reasons.

Also hate to point something so obious out, but the world dosent get heavier when someone builds something here out of material that was already here - Coruscant on the other hand was built with material from across the galaxy, mined elsewhere.

Perfectly true, although you can also alter orbits in other ways, usually by giving up the evivalent amount of energy - seeing as matter and energy are just the same things in different forms - anti-gravitons or something similar would probably work - I assume thats what repulsorlift and tractor beams operate on.

 

I don't think you are far off the mark, but this probably hasn't been talked about much because of the unlikihood of adding significant extraterrestrial weight to the Earth. First, let me know if you think this assumption is way off base...

I would say that the amount of material brought to Coruscant doubled the weight of the planet. Does that sound reasonable? I'm not talking just buildings (Although they represent a significant portion) I am talking about humans(and Aliens), their spacecrafts that got them there, the supplies that MUST be imported (Corscant basically has no place to cultivate crops/animals for food, at least not in the amount that would be sufficient to feed coruscant's population), human/alien waste, huge bronzium statues brought in by people like Palpatine...that's starting to add up to A LOT of offworld weight. I think double the original weight is not pushing it.

Going by the laws of planetary motion, we have... G * M = 4 * (3.141592..) * R^3 / T^2....where G is the gravitational constant of Coruscant's Sun, R is the Radius of the orbit, and T is the time it takes to orbit the Sun one time. Now, make it G * 2M = 4 * (3.141592)*R^3/T^2. Isolating G, setting the equations equal, and Canceling out M and 4*(pi) you are left with 2* (R1^3/T1^2) = (R2^3)/T2^2). Either R or T must change, and I am not sure what would be more apt. I think maybe Time is most likely. This would be consistent with F=ma. The Force (As in physics, not Star Wars) should remain constant. Increasing the mass would decrease acceleration, causing the planet to move slower and thus increase it's orbit time.

I'm not the greatest physics person ever, so I could be wrong, but it seems to me that adding tons of mass should change SOMETHING, even if it was gradual.

Carnage

 

Bringing all that down to Coruscant would not come anywhere near doubling its mass, but using doouble the mass to work your example is fine with me. Note the figures I gave for our entire asteroid belt as compared to earth.

Make no mistake that my knowledge is conceptual and I would have no idea how to work the equations(s?) you just did, but I notice you say the acceleration would slow. The planet is not accelerating at all, it's at a constant speed along its orbit. You would have to impart an acceleration to change the orbit.

 

It would change, but not in any measurable amount. Kinda like how a slignshot orbit slows down the rotation of a planet - it happens, but on the big scale it doesn't matter. Coruscant's sun will turn into a cold lump long before the orbit is distrupted.

 

Not in the slightest. You really have no idea how much you are talking about here, do you?

Why on earth would you think that?

The average building is 5 miles high. Most of it is empty space, and then there is the space between buildings. Lets treat it all as one solid block. Lets say its as dense as iron - which makes it over ~7x as dense as people, food, and waste are gonna be. Also, lets use the surface area of earth instead of coruscant for emphesis.

That works out to being 3.24*10^22 kgs. Or 0.56% of the planets mass. Not even close to double.

Acceleration is due to gravitational atraction. Increase in mass results in an increase in gravitational pull, which results in higher acceleration.

It will change, just not in any meaningful way.

 

Assuming a completely circular orbit (It's not as complicated as elliptical orbits) every move that the object makes is changing it's vector slightly. A constant velocity only works in an object moving in one direction forever. An object travelling in a circle (Such as a planet around the sun, or a watch being swung on a chain) is changing it's vector constantly which is due to a constant acceleration. This type of acceleration if centripetal acceleration. The below is a small passage from a good wikipedia article on centripetal movement. (I know, Wiki can be wrong, but this article is pretty much consistent with other information.) Most of the article is highly mathy, so it may not be interesting. Although, For "not knowing" how the equations worked, you seemed to understand enough to think my inputting acceleration could be wrong so you probably could work the equations more than you think.

And yes, Doubling may have been foolish of me, as that does seem a little absurd, but the number 2 is easy to work with. As I noted before though, Coruscant probably has WAAAAAY more available resources than our asteroid field. I didn't work any numbers, but I'm thinking even a 1% increase in mass could have large effects. I am not fantastic with physics, but I dabble in it once in awhile (Had to take quite a bit in college) and this question intrigues me.
http://en.wikipedia.org/wiki/Centripetal_force

Objects moving in a straight line with constant speed have constant velocity and require no force to do so, since they experience no acceleration. However, an object moving in a circle at constant speed has a changing direction of motion. Since velocity is a vector with both speed and direction, a changing direction implies a changing velocity. The rate of this change in velocity is the centripetal acceleration.

Carnage

 

I had to do a little digging and wanted to word this right, but instead I'll just copy and paste what I found. It's on a page talking about moving Mars to earth's orbit and someone explains that by just adding mass it won't happen. They use the ISS orbiting the Earth as an analogy:

Orbital trajectories are independent of mass. You could double, triple, or even octouple the mass of the ISS and it wouldn't matter. The shuttle can dock with the space station without pulling it down because it's in a matching orbit that just happens to be right next to the space station. While it's true that increasing the mass of the ISS does increase the gravitational attraction between the combined mass (shuttle + ISS) and Earth, the total attraction is no more than the combined attraction of the two separate bodies. Much like two similar pendulums swinging in synch with each other will continue to swing at the same period if you happen to link them together, two orbiting bodies in the same orbit will continue in the same orbit if you link them together.

So my under-educated understanding of this is that adding mass to Coruscant will not effect its orbit unless the mass increase rivaled the mass of the star it orbits.

 

Now THAT is interesting. Any chance you can give me a link? I will concede defeat but it makes for something very interesting for me to think about in light of equations (Which I will stop posting, but will think about personally. ) such as K.E. = 1/2MV^2...if the mass changes and the velocity doesn't...the kinetic energy does and that sounds odd.

Carnage

 

The space shuttle ISS example sounds like it has to due with the fact that in order to match up with the ISS, the shuttle has to already be in a stable orbital pattern that matches the ISS, thus it has the same velocity and motion as the ISS, and when the two link, they both are moving at their original speeds.

To bring things to Coruscant, you have to match Coruscant's orbital velocity and position, so any added material will already be in a stable orbital period. If the materials were never added to coruscant, they could just float free in the same orbital path as coruscant.

 

The page is from halfbakery where, if I understand this right, someone will post some oddball idea and people will chime in to say why it would work or why not.

Halfbakery.com

 

Going back to the original example I think I know what the person Excellence was talking with ment. The terms weight and mass are not right because as long as the damn was build with materials here on Earth there would be no mass/weight gain. However if the damn was built on a plate and the plate sunk as a result the Earth would "shrink" a little or become more dense. I don't believe that would effect the orbit (unless perhaps it happened very violently) but what it WOULD do is cause the Earch to rotate faster. It would be like when u spin in a chair with your legs and arms out then pull them in quickly... you spin faster.

This actually happened with that earthquake that caused the tsumami, scientists found small but mesurable differences in the earth's rotation as well as it's axis.

This could very well happen on Coruscant either way. If more light mass is added and the size increases rotation could slow down. If the plates get squished and the planet gets smaller the above could happen.

 

Coruscant has moon(s) right? Although I'm sure this would be technologically accounted for, let's say, for the sake of argument, that they don't. Would it be possible that the increases in Coruscanti mass (especially since they just build on top of existing layers of structures rather than remove them) could have a Sernpidal-esque effect on Coruscant's moons?

 

One point: the whole world has now been rolled millions of kilometres closer to the sun.

 

No wonder the view from the top seemed to change! I just thought SYS Hall was snuggling up to it!

In any event, shouldn't Coruscant's heat cause it to melt, or did the magic-science step in and solve that ex post facto?

E_S

 

Each building is self contained, and have their own shields (AOTC ITW), so having special radiators ala starships is not far off. So yes.