# Playing boules… IN SPACE!

Boules is a range of relative games played with small, heavy steel balls thrown on a court, such as the French Petanque and Italian Bocce.

While there is variation between games in terms of how and why you thrown, and what the size of the court is, they all rely on the distinctly Earth-bound fact that thrown balls will eventually come to a stop at fixed relative positions on the ground.

Now, suppose that we want to play on a space station, in zero gravity. There is no "ground". Can we devise a boules-like game, ideally similar to Petanque (i.e., everyone plays from the same position, the court need not be specially prepared, at least two dimensions of court are exploited, points are scored by some measure of proximity to a target) playable in a space where you can't rely on gravity to keep your thrown balls in place?

• Would an answer that required a prepared court be acceptable, or is that the key part of the question? – Starfish Prime Sep 1 '19 at 19:48
• Acceptable only if you prepare your court using means other than magnetism, or electrostatic attraction. – Willk Sep 1 '19 at 20:10
• @Willk you got me :-( I have, at least, not merely tried to simulate in-gravity bowling by using some other force. – Starfish Prime Sep 1 '19 at 21:28
• Pétanque - we like our diacritics ;) – Quentin Sep 2 '19 at 11:42
• There was ~35 years ago a similar question at the International Physics Olympiad, but about dancing in gravity. You need among others to account for momentum conservation, so also take into account your own movements (not only the ones of the boules) – WoJ Sep 2 '19 at 14:02

Trying to recreate a game intended to be played on a flat surface in a gravity well whilst in a microgravity chamber seems not only futile, but it also passes up an opportunity to create a new game that makes better use of the features of the environment that hinder conventional bowling.

My suggestion: orbit bowling.

Set up the court by placing the target (call it a sun or planet or black hole; whatever takes your fancy). This object floats in space and is given a generous electrostatic charge by a small van de Graaf generator ahead of time. Collision of the target with a wall or other non-game object ends the round, and may involve a forfeit for the placer. The setup therefore requires a little skill (because perfectly stationary placement may be impractical), and players take turns setting up the court for each round.

The objective of the game is to throw your bowls such that they enter into an electrostatic orbit around the target for a) a certain amount of time (the length of a round, probably quite short) and b) that has a lower periapsis than all your opponent's bowls (alternate rules might require circular orbits or at least ones of limited eccentricity, but that sounds dull). Bowls that crash onto the target and stick are non-scoring. Such a move might be considered a round-losing foul under some rules, but that seems like it would discourage risky play and make the game a little less interesting.

Your bowls are made of a suitable lightweight material (perhaps expanded polystrene foam? heavy bowls would be better, of course, but you start running into safety issues involving field strengths and dielectric breakdown...) and are suitably charged before the throw by an appropriate means (rubbing them on a foam sheet sounds like a reasonable method, but maybe you could have a little van de Graaf of your own). You may charge your bowls with the polarity of your choice, but to win you'll need at least one that is attracted to the target. Like-charged bowls won't orbit the target, but may be a good means of disrupting your opponent's bowls without having to hit them directly.

This game maintains the basic goals of bowling-type games, whilst giving them a new and uniquely space-oriented theme. In a suitable fictional setting, it might also help practise certain kinds of orbital mechanics...

He cheats a little by moving the target slightly to stop the orbit decaying. You might perhaps be able to take a leaf out of the book of curling and make it a team game where one player bowls and the other player (or players) on their team have limited means to shepherd the projectile and help inject it into a more stable orbit.

• Decaying orbits is going to be a killer if youâ€™re playing in an atmosphere. – Joe Bloggs Sep 2 '19 at 11:44
• @JoeBloggs very much so... that's what drove requirement (a) (orbit must last for the length of a round, probably quite short). There's a tradeoff to be made between mass of the bowls (to reduce the effects of drag) and the safety of having a massive electrostatic charge on the target. I'm too lazy to work out a reasonable choice of material and charge... playing in a vacuum sounds like a reasonable solution ;-) – Starfish Prime Sep 2 '19 at 12:50
• But if playing in a vacuum then orbits become impossible: the best you can reasonably hope to achieve is a fancy slingshot. Not that Iâ€™d object to watching a game of increasingly convoluted slingshot manoeuvres... – Joe Bloggs Sep 2 '19 at 13:05
• @JoeBloggs unless your initial throw injects the bowl directly into an orbit, of course. This isn't like performing satellite-to-satellite or surface-to-orbit manoeuvers, so an additional circularisation "burn" may not be required. – Starfish Prime Sep 2 '19 at 13:10
• Well, yes, but the projectile will always pass through where you threw it from, so itâ€™s less of an orbit around the target and more an orbit within the playing area. Of course, if dodging previously thrown balls is part of the game then that could be an advantage... – Joe Bloggs Sep 2 '19 at 14:36

# Cotton balls

Something with a high drag-to-mass ratio will quickly slow down and come to an effective stop before it reaches a bulkhead. Cotton balls or similar will work. (Perhaps even marshmallows might work.)

This presents a 3-dimensional version of the game, with slight "terrain" based on air currents. Speaking of that, while all unsecured objects in a microgravity environment will wind up against the nearest air vent, that's not so quick as to render such a game unplayable - you just can't walk away from the game during a round and come back later.

• this is exactly correct. – Fattie Sep 2 '19 at 16:16
• I'd guess just a "scrunched up piece of paper" would also work – Fattie Sep 2 '19 at 16:19

Overhand throw.

Petanque generally implies a underhand toss, and the ball describes a gentle parabola as initial upwards trajectory is converted to downwards via gravity.

In your space game the ball is thrown with an initial downwards trajectory, in a manner akin to a cricket pitch. As in petanque, the place where ball makes contact is the player's play. In certain circumstances banked shots off of the ceiling or walls are allowed if called in advance; no slop space petanque. In your space petanque the ball might ricochet upwards and away from this initial place of impact and be retrieved by a floating space dog; no matter - the ball has a chalky coating and leaves a chalk mark to register the hit.

Other variations include sticky glue balls which stay where they hit. Or the manlier version involving spiked balls (which leave holes on the court; no concern to you if you are the spiked balls type of manly).

• "sticky glue balls which stay where they hit" How do you throw it? – user Sep 1 '19 at 20:40
• @aCVn teflon mitts? – Starfish Prime Sep 1 '19 at 20:43
• The kitchen staff and engineering crew who pass the time playing space petanque will enjoy watching you figure it out, @aCVn. There are tricks. Probably if you buy them all a round they will show you some; watch carefully for the rest. Dry ice gloves might be allowed for cute newcomers. – Willk Sep 1 '19 at 20:47
• Why require it to stick? With a gentle enough throw and a decently thick atmosphere you can pitch the ball to a standstill in open space... – Joe Bloggs Sep 1 '19 at 21:31
• @JoeBloggs - I like it. And it would be more like petanque. The floating ball is tapped gently into motion with a finger such that its (eventual) impact with the ground brings it to a halt there. Also everyone can "throw" at once, the balls moving off in a gently flock. – Willk Sep 1 '19 at 21:45

Underwater boule.

The field is a sphere of water, few meters in diameter. The center of the sphere is made clearly visible.

The players float in microgravity outside of the water sphere, and launch their balls inside the sphere.

Goal of the game is to get as close as possible to either the center of the sphere or to a target ball.

Water drag will take care of dissipating kinetic energy via drag, and microgravity will prevent them from sinking.

• This may require a specially prepared room, to ensure that it won't care about water droplets potentially getting sprayed everywhere upon a ball entering or leaving the sphere. – Kyyshak Sep 2 '19 at 10:15
• @Kyyshak, true, but a specially prepared room is needed for any sport, even on Earth. – L.Dutch - Reinstate Monica Sep 2 '19 at 11:08
• @L.Dutch Not any sport. Petanque in particular can be played on any vaguely-close-to-flat surface of sufficient size. – Logan R. Kearsley Sep 2 '19 at 13:41
• @LoganR.Kearsley, I assume you never had kids playing baseball in your living room ;). Also size is part of the special preparation. – L.Dutch - Reinstate Monica Sep 2 '19 at 14:25
• @L.Dutch Not specifically baseball, no... if they were a little older, I wouldn't put it past them! – Logan R. Kearsley Sep 2 '19 at 15:54

I'm going to start by considering the difference between boules and lawn bowls.

In boules part of the principle is to throw the ball directly to target point usually on a surface on which they would not roll well. In bowls one rolls the ball to target point. In both cases the target is a cochonnet or jack "placed" initially by one of the players. For these purposes there's minimal distinction between the two.

Since coming to a halt is not a thing in space, we need to consider the dynamic equivalent, which is a stable orbit.

The indoor version

Played inside a cylinder section of a space station or other similar with a surface that's free from obstacles. The jack is placed by throwing it hard enough that it enters a steady orbit within the cylinder. The winner is the person who's boule most closely matches the orbit of the jack.

Here we find the difference between boules and bowls coming though.

• Boules is played on a high friction surface and the jack will eventually come to a halt. Scoring is done in the familiar manner.

• Bowls is played on a low friction surface and game is time limited by the rolling friction of the balls on said surface. Scoring is a matter of who most closely matches the orbit of the jack.

The outdoor version*

This is played by putting the jack into orbit around a planet or other suitable body. From the sundeck of your space yacht or station, boules are thrown into an orbit that should most closely match the orbit of the jack. Scoring is done using the indoor method for bowls.

*because why not? Sure there might be some casualties if the kids don't clean up after their game, but who hasn't stood on a lego brick with bare feet in the dark.

## No Real Change is Needed

Objects inside a space station are eventually going to come to "rest" assuming your space station has an atmosphere. Drag is going to slowly rob your boules of momentum, until they hang floating at some position.

So the skill aspect of the game is to determine where your boules will end up floating. Bounces - both against surfaces and other boules - will also eat up some momentum.

The ability to bank shots off the "walls," "ceiling," and "floor" will make this game very interesting. Over large distances, the aiming well enough to hit other boules may be a significant challenge too. I would totally play this game.

## Considerations

• You probably don't want heavy boules. Heavy objects are going to have more inertia, so they will travel further. Drag force is a cube of speed - so lighter boules will start quickly, but slow down very rapidly, whereas heavy boules will start more slowly and then just.... keep going, given the same starting energy.

Also, lighter boules are less likely to damage equipment, people, etc.

• Your station probably has a bunch of fans moving the air around for cooling of equipment, and to prevent undesirable gases from building up in specific locations. This is going to add an extra challenge to your game - boules that stop near vents may end up propelled into motion again as they drift into the currents.

• Finally, the game will never completely come to rest. Micro-gravity and air currents will move the boules over time. Probably want to put a time limit on turns to prevent unsportsmanlike behavior.

A light adhesive ball. Preferably because the ball has a metamaterial surface rather than an adhesive glue-like substance.

On earth the balls have a certain resistance with the ground that slows them down upon contact. With an adhesive surface your balls would stick to the surface of the ground as long as you dont throw them downwards too hard and then roll to a stop. By manipulating how adhesive and elastic the balls are you can change the chance they'll bounce off and how much resistance they generate on the surface before rolling to a stop.

# Guess the length

Instead of rolling the ball and have it slow down due to resistance (where you'd need to guess the power of mew) have the ball attached to string with negligible elasticity. The target is thrown out with a length and players then have to guess how far by measuring out the string and throwing in the right direction.

Maybe there could be a holder at the start line which you use to secure the length of string you'll use and then just push off. In addition, the target could be attached to the same holder and if it is hit it can still move, but resistance is provided by this holder.

# Create resistance elsewhere

The idea that the resistance being supplied by the holder for the target gave me a second solution: That you just use this method for all balls....

Both games can be played 3D or 2D (if you specify the plane that the balls are shot off at.