Is it ever mentioned in the Star Wars movies why a sphere-shape was chosen? It would seem that sphere would be unreasonably hard to make as molding all the outer plates perfectly requires every plate to be unique... Also, wouldn't the size of the space station generate some kind of gravitation field towards the center? This doesn't seem to apply, though, as the people inside seems to be affected by some kind of fake gravity towards the floor. Wouldn't it be better if it was just shaped like most other space ships?
Everything with mass has gravity between it and each other thing with mass. There's gravity between you and your computer, but it's too small to have any noticeable effect.
For the effect to be noticeable, at least one of the bodies needs to be big, and not too far away. For example, the earth is big enough to keep us on it unless you have a big, powerful rocket. The moon is big enough and not so far away that it causes tides. The sun is big enough to keep the earth in orbit.
Gravity can be calculated as a tiny constant multipled by the mass of one object multiplied by the mass of the second object divided by the square of their distance. F = G * m1 * m2 / r^2.
So the Death Star: "It's colossal, the size of a class-four moon". But how big exactly? Wookiepeedia says:
A recent Reddit post puts this into context:
That said, it still has some effect on other astronomical bodies, but not a significant one. To give you some idea, given the mass I calculated above and a radius of 80km, it would have a "surface gravity" of 0.7067 cm/s^2 which is 1 / 1388 the gravity of Earth. If you weighed 180lbs on Earth and were to "stand" on the hull of the Death Star, you would exert a force of about 2oz.
Others point out that the ship had artificial gravity generators, it's mostly all aligned up-down decks, so the ship's own natural gravity wouldn't make any noticeable difference. Wookieepedia again:
Also from Reddit:
Finally, for something travelling in the vacuum of space, shape doesn't matter as there's no wind resistance. Other ships need to land on planets and fly in their atmospheres, but not the Death Star which was constructed in space.
The triangle, letter X and square had already been used. Only the blueprints were smuggled out of the Empire, but many Bothans died to smuggle those blueprints. I fear the answer died with them.
Agreed. This is why they had to double their efforts to finish the Death Star before the Emperor arrives in Episode 3.
You can make a perfect sphere out of small hexagon shaped panels that are all of the same size. You would only need uniquely shaped panels if it was
True, but the Death Star is mostly hollow. At it's center is a large empty chamber that contains the reactor code, and then the structure is made up mostly of rooms and hallways. It would not weigh the same as an asteroid the same size. Also, if you were to stand near the center of the Earth, then which way is gravity? It's pulling you in all directions. So people
If you made all the rooms and hallways curved around the shape of the sphere, then rooms near the center would not have flat floors. You would not be able to see the end of a long hallway, and stacking cargo would not rise upwards in parallel to each other. It would be more trouble and have no benefit. So creating flat floors that run parallel to the equator is more effective, and if all the floors are parallel to the equator then you need gravity plating.
Here are some good reasons to make a large space station the shape of a sphere.
In the first movie, Luke mistakes the Death Star for a small moon the first time he sees it, as shown in this clip. There isn't any further implication that the Death Star was MEANT to resemble a moon.
In the novelization, however, there was a passage about the Death Star being covered in lights that could be turned on and off to mimic the phases of the moon. That's really kind of ridiculous, though, since when it comes close to a sun, it would show the phases of a moon naturally.
If the Death Star was sufficiently massive to generate a gravity field, as seems likely, the artificial gravity system would probably have been designed to counteract it. The Earth's moon has gravity one sixth that of the Earth. A "small moon" would have less.