Reactionless (sex) drive

sailor.barsoom wrote:

> On another group, the subject of sex in zero-G has come
> up, as it does from time to time. There were the usual
> predictions that the couple would have difficulty
> "getting it together" in Space, and that if they did,
> that they would bounce off of the walls like popcorn.

I'm always amazed at the depth of inexperience such pundits must have.
I mean, I'm no Don Juan, but I can imagine a good half-dozen techniques
that don't rely on gravity at all. (And as for bouncing off the walls,
the same elastic pinned-to-the-wall sheets you use for sleeping would
solve that problem for not sleeping as well.)

> It was suggested that only the use of bondage gear
> could solve these problems.

No, that won't be the only solution. (Though perhaps a fun one.)

> I disagree. I suspect that the solution to all of this
> perceived difficulty is really quite simple: hold on to
> your lover.

No kidding.

At the risk of being crass, wasn't there some porn video that was shot
on zero-G (in a parabolic aircraft of course) a while back? Perhaps the
best way to convince the doubters would be to get ahold of that, and
have them watch it.

> Now, if John and Mary are hovering in the center of
> this cube (we'll assume 5*5*5 metres) and John shoves
> Mary west, then what happens is that Mary heads west
> while John heads east. If John is more massive than
> Mary (a statistical likelihood), then Mary moves more
> quickly and reaches the west wall before John reaches
> the east wall. Each has the same energy, the same
> momentum; it's just divided up differently between
> speed and mass. And since each has the same momentum
> *in the opposite direction,* the total momentum is zero.

All true.

> Thus, if John shoves Mary west, *and they hold on to
> each other,* then more-massive John moving slower in one
> direction cancels less-massive Mary moving faster in the
> opposite direction. They can't, as a unit, go anywhere.

Basically right; as long as they're connected, then if they're not
touching anything, there's no way they can accelerate in any direction.
If they could, that'd be a reactionless drive, as you say.

Of course they are touching something: the air. So it is possible for
either or both of them to "swim" in any direction. But this is a pretty
slow and inefficient process, as any astronaut or tourist who's ended up
swimming in air will attest.

> But then, how fast are they likely to set themselves
> moving, just bumping against the wall? Slowly drifting
> seems much more likely than frantic zinging. My guess
> is that to have them bouncing around like a 3-D billiard
> game, they'd have to do it on purpose.

Agreed.

And if your pundits think that gently bumping into things is going to be
any deterrent to sex, see aforementioned comment about amazing depth of
inexperience...

Cheers,
- Joe