A question about gravity

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Lorsa Lorsa's picture
A question about gravity

I just felt like I should ask a question about gravity, despite the fact that I should be able to figure it out by myself. Classical mechanics can be such a mess though so better safe than sorry.

I just started GMing a campaign I hope will take place a lot in Earth orbit, including the lagrange stations and Luna. It really is a great place for all sorts of funky stuff, I can't believe I overlooked it before (it seems like Rimward or Mars is more alluring for some reason).

Anyway, it is quite easy to think that a station in low enough orbit will feel some sort of gravity from Earth, so that even though it's small, there will be some sort of down. But then I realised that if you are in a stable orbit you will effectively be in constant free fall and since you and the station will be under the effect of the same acceleration you will in effect have a zero-g environment in the station.

It can get really tricky understanding these things as they aren't always intuitive. Also these very low-g places can be very hard to visualise (especially for some players) so any tips on how to explain them is more than welcome.

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Undocking Undocking's picture
There are a bunch of youtube

There are a bunch of youtube videos of planes on parabolic flight paths safely allowing the passengers to experience free fall. The easiest way to explain it is to show one such video and talk about how orbits work: the orbiting object is being pulled towards the gravity well, but the orbiting object is moving fast enough to miss—which, in habitats without a large enough mass, causes free fall. If that doesn't work, point out that the ISS is in LEO, and it has free fall.

Unless an orbiting object has enough mass for its own gravity well (Luna) or creates the illusion of gravity (torus) then it will have microgravity.

For visualizing such stations, there are a bunch of videos shot within the ISS that you can show, and EP has some great art of cramped micrograv living.

nezumi.hebereke nezumi.hebereke's picture
Undocking is right about

Undocking is right about orbiting. Imagine yourself in a falling elevator, except that instead it misses Earth.

Imagining living in microgravity is extremely difficult. EVERYTHING acts differently. Fire, liquids, sleeping, head size, everything! For that, I'd try to things:
1) Yeah, videos help. Watching videos tells you how things work. Chris Hadfield especially does a lot of great videos.
2) Remember this is the future, and they have tech for that. Most of the issues of space travel have been solved with super-cool, behind the scenes technology.