I'm talking about something like this, for comparison's sake:

enter image description here

How would artificial gravity generated by centrifugal force affect the people living aboard such a ship? Let's assume that the central shaft and the asteroid itself rotate independently of each other, with the central shaft (a residential tower of sorts) rotating either clockwise or counterclockwise while the asteroid (and thus the verdant pastures on the inside of the "shell" used for farming and agriculture) rotates the opposite direction. With those assumptions out of the way, here are a few questions.

(1) How fast would the central shaft and the asteroid each have to rotate to generate the equivalent of 1g? For the sake of this example, let's say the shaft is somewhere between 500m and 1km thick and the asteroid is 10-15km in diameter.

(2) Would people growing up in a constant 1g of artificial gravity experience any of the usual effects of prolonged space travel on the human body, such as decreased bone density, muscle loss, an increase in height etc.?

(3) If you lived on the surface of the residential tower, what direction would "down" be oriented in? Could you stand "up" perpendicular to the tower and walk down it like a Sunday stroll down Main Street, or would the artificial gravity instead hold you parallel to the tower like a rock climber or a caterpillar climbing up a tree? What direction would fluids and other solids be drawn in?

(4) If you fired a bullet, pitched a fastball, or tossed your drink brimming with Viking rage, how would they behave the farther they traveled from the tower? I assume a bullet wouldn't be meaningfully hindered by the tower's rotation and would continue traveling until it hit the wall of the asteroid, but what about objects thrown or launched with less speed? How far would you have to go from the tower to be completely free of the artificial gravity?

This would really help me understand what daily life inside such a structure would be like (I'll have questions regarding thrusters at some later date).

  • 4
    $\begingroup$ This asks multiple questions as one. It’s best to ask one question per Question! #2 in particular is a very different question! $\endgroup$
    – JDługosz
    Oct 16 '16 at 1:28
  • $\begingroup$ Your multiple questions are not a problem, as then are pretty simple, but your understanding of how centrifugal force works, is concerning. 1)you should just calculate it $a=\omega^2r$ 2) they should be fine, as on earth at 99.9% 3)that is concerning part of your Q 4)JDługosz answered kinda. ; I would recommend to start from reading links from that answer worldbuilding.stackexchange.com/a/46325/20315 and some trough of using asteroid as station here worldbuilding.stackexchange.com/a/45304/20315 $\endgroup$
    – MolbOrg
    Oct 16 '16 at 22:07
  • $\begingroup$ So for a tower 1km in diameter to have 1g of gravity, you'd need to rotate it at 70 m/s? Is that correct? $\endgroup$ Oct 16 '16 at 22:37

The centrifugal force is directed away from the axis of rotation. If you spin a barrel you are pushed against the inside wall. If you draw the building and label the axis, we can verify your specifics regarding the tower in point 3.

Here is one of many results you get if you ask Google for centrifugal force calculator. And here is a straightforward presentation of the formula so you can do it yourself.

Fc = mv²/r, where Fc = centrifugal force, m = mass, v = speed, and r = radius.

For point 4 you can understand it with an illustration. Draw the (straight) path of the thrown object, and overlay the rotating surface where the observer is standing, to visualize the complex motion perceived. See also Coriolis force. You can probably find videos for that.



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