Sup. So I've been researching some stuff for a story, and

increasing the rate of axial spin doesn't make the gravity stronger.

venus rotates super slow but has nearly the same gravity as earth

>>8022815
>increasing the rate of axial spin doesn't make the gravity stronger.

I know. But wouldn't the rotation have some sort of effect on centrifugal force or something? Like the whole theory of creating artifical gravity by having a rotating craft?

>>8022817
>sort of effect on centrifugal force or something? Like the whole theory of creating artifical gravity by having a rotating craft?
Centrifugal force pulls outward.
What board are you from, Anon?

>>8022824
Ok, centrifugal isn't the one I meant. I meant centripetal. I think I do, anyway. The whole thing of a rotating craft creating centripetal force that would push us down onto the surface to create something that feels like gravity?

>What board are you from, Anon?
>implying people on 4chan only visit one board and should be judged by which boards they visit
Also see
>Bear in mind I'm not expert by any measure of this kind of stuff

I'm asking because I don't know, irrespective of which boards I do/do not go on.

>>8022831
Rotating craft create an apparent force pushing you *outwards*, causing you to feel an apparent gravity-like force pinning you to the *inner* surface.

It's the same principle as how you feel heavier in an elevator accelerating upwards- because an object in motion would "prefer" to continue moving in a straight line, it needs to constantly accelerate inwards to be pulled into a circle.

Spinning the planet would make the gravity appear to be (very slightly) *less* on the equator - as is, in fact, true on the Earth. (It's not a very big difference.)

>>8022851
So, increasing the rotation of the Moon wouldn't do a thing?

...That now begs the question, why do I keep reading in modern sci-fi the idea that spinning a planet does change it?

>>8022806
OP, basically the only way your idea would work is if you hollowed out the entire moon and lived on the inside and made is spin really, really fast.

You need to do some research to figure out how artificial gravity works. Your plan only works in ships because they're small scale.

http://www.school-for-champions.com/science/gravity_artificial.htm#.VxpiapUrKUk

>>8022859
What exactly have you been reading? How do they increase the spin?

>>8022888
I'm trying to figure that out now. It's a book called Leviathan Wakes, in the series called The Expanse. The only references I can find, either in the book or online, about is simply:

>from the book
"Spinning [Ceres] up to 0.3 g had taken the best minds at Tycho Manufacturing half a generation..."

>online
"Tycho was also responsible for the decade-long endeavour of building the reaction drives of the asteroids Ceres and Eros, forcing them to spin and create gravity so they could be colonized."

So it's really vague, but all they state is they used the body's spin to create gravity. I thought I'd read it in another novel, but that was something different and nothing to do with creating gravity.

>>8022888
Also from the series' wiki:

"Ceres isn't big enough to have gravity on it's own so they've hollowed out the thing and spin it to produce artificial gravity. Things don't go straight up and down in centirifugal, artificial gravity, hence the coriolis effect."

Must've missed when they said they'd hollowed it out. Alright, so by hollowing it out then spinning it, theoretically it could produce "artifical gravity" through centrifugal force?

>>8022896
>asteroids
The theory that has earth like gravity and asteroids in it is to drill a cylindrical hole in one and start spinning it for centrifugal apparent force. Not live on the outside. There is no point in living on the outside of an asteroid.

>>8022902
as it spun around, if you were below the surface standing underground looking up (up, in this case, being towards the core), you would feel a downward pressure that is very like gravity, but is really just a constant acceleration acting on you. as you moved towards the center of the rotating object or away from the equator towards the poles, the feeling of gravity would lower and eventually fade away.

>>8023050
Acceleration = gravity

>>8022902
>>8022896

Wtf this is just stupid
You'd not only need to hollow out the planet so much that you cozld live under the surface you'd also need to spin so fast that it NEGATES the inherent gravity and then spin it even faster to have it have Earth gravity and seriously the asteroid would just rip apart if it spun that fast.

The only way we'd be able to increase Moon's gravity is by increasing its mass (dropping asteroids on it) and even then it would be silly, it would create enormous tidal forces on earth.
Say hello to mega waves and tsunamis and shit

>>8023050
>>8023033
Oh. That makes sense.

>>8023063
>the asteroid would just rip apart if it spun that fast

Ah. That's a fair point, I hadn't really considered that. Looks like my idea is a load of arse then. Thanks for clarifying it folks.

>>8022831
>and should be judged by which boards they visit
Oh, /mlp/.

>>8022806
General relativity predicts that gravity is related not just to mass, but to the whole stress-energy tensor, coding in some sense the energy density. So yes, the gravitational pull of the moon would augment, but I don't thing that it would even be measurable at any spin at which the moon would stay whole...