# Sports in Rotational Artificial Gravity

1. Jan 11, 2012

### Algren

This is a spoiler for all Artificial gravity space crafts. If somebody thinks that he can do whatever he can on earth, on the Space Craft, then here is bad news:

No football, no soccer, no cricket, no birds can exist on the craft without confusion.

Here is why:

A projectile in the space-craft will not go along with the usual Newtonian-gravity equation. Once in the air, a body wont experience w^2 * r force.

I have already derived the equation for the curved range, i.e. range on the rotating surface, if a projectile is projected from a hieght 'h' and it hits ground in the end. I have made a C++ program for it: Here (it also gives the aberration of range from normal earth-based projection)

But, i did that ignoring the viscosity if the rotating atmosphere along the craft. Well, that is why I came here . I need to derive the same, but considering varying velocity of atmosphere, and viscosity.

Last edited: Jan 11, 2012
2. Jan 11, 2012

### technician

You have a great point here !!
Essentially if an object is released from the hand in a rotating space station the object continues in a straight line (tangent) at constant speed to an outside observer and will not 'fall to the floor' as on Earth.... it is better to say that the floor comes round to meet the object.
The object will hit the floor behind the expected point if gravity were responsible for the motion.

3. Jan 11, 2012

### Staff: Mentor

If we propose a really large space, enough to fit a football pitch/cricket green an interesting thing to take into account would be the difference between sending the ball spinward and anti-spinward. If you kick/bat the ball in the direction of spin then it will travel less distance than if it is kicked/batted in the opposite direction of spin.

Of course if living in artificial gravity for any length of time does occur and people want to play sports they could always invent interesting new ones.

4. Jan 11, 2012

### Algren

That is exactly what would happen. But table tennis and badminton can always remain options.

Please check the program. Enter '0' for hieght if you are just checking for very small hieghts.

And also, any rpm less than 2 is recommended.

In the doubt that the segment would describe a parabola if circle is stretched to a straight line, i derived the formula.

5. Jan 11, 2012

### Antiphon

No only that, there would be a preferred direction for staircases; I just don't know which way is preferred.

If you climb stairs in the same direction as the rotation it's a harder climb but the chances of falling down the stairs is reduced. Going the other way it's the opposite.

6. Jan 11, 2012

### Staff: Mentor

If you are living in less than 1G making it harder to climb up the stairs would be a good way of building exercise into the environment to make up for muscle and bone atrophy.

7. Jan 11, 2012

### technician

If climbing stairs takes you towards the centre of rotation then less force is needed as you get closer to the centre of rotation.

8. Jan 11, 2012

### Staff: Mentor

9. Jan 11, 2012

### technician

Half way to the centre of rotation and the force will be halved.

10. Jan 11, 2012

### Staff: Mentor

And if it's an O'Neill cylinder 8km wide then someone climbing 3m to the next floor should be negligible :tongue2:

11. Jan 11, 2012

### technician

Nice one Never heard of an O'neill cyclinder.
My station is a simple torus rotating about its centre.
Must look at this O'Neill thing.
Cheers R-m-b

12. Jan 11, 2012

### bbbeard

There is a memorable scene in 2001: A Space Odyssey which shows one of the astronauts jogging on the inner surface of the rotating hub that provides artificial gravity for the humans. A moment's thought suggests that jogging "with" the rotation could be noticeably harder than jogging "against"....

BBB

13. Jan 13, 2012

### Algren

So, in the cylinder, we can have stairs which take you from ground to ground, with changing force needed every step.

But, I dont guess we would be ever able to replicate even earth-nature in the cylinder. Birds will not be able to fly in any rotational craft.

14. Jan 13, 2012

### technician

The cylinder idea is a distraction!
If the radius of the spinning "station" is made large enough then climbing stairs of a sensible length can be made to produce effects that are 'negligible'
The cylinder geometry does not change the basic principles.
Half way to the centre of the cylinder would produce half the force

15. Jan 14, 2012

### Algren

I wrote 'cylinder' instead of 'rotational artificial gravity spacecraft'

Oh yeah, one more problem, we cannot have bullet-train high speed transportation against/along the direction of the crafts rotation without some serious changes in gravity.

i.e. perhaps ± 4m/s^2

There is only one solution:

The train will travel perpendicular to the direction of rotation.

The only structure which makes such transportation favourable is the helix. can there be any other?

And apparently, niether the cylinder, nor the torus will be favored by this travel.

Last edited: Jan 14, 2012
16. Jan 18, 2012

### NOAM

I suggest games such as chess,checkers and marbles.As for adrenaline junkies,badminton and table tennis should do.Entertainment based games such as shown on the TV series Minute to Win It and be tried(which might sometimes add or subtract the difficulty level).To achieve physical fitness gymnastics is a good choice.