no "up" or
"down"; where nothing ever falls; and where, if people were there,
they would float about with their heads pointing in all directions.
This is not a fairy tale; every word of it is scientifically true. If
we had some way of flying straight toward the sun about 160,000 miles,
we should really reach this strange place.

Let us pretend that we can do it. Suppose we have built a machine that
can fly far out from the earth through space (of course no one has
really ever invented such a machine). And since the place is far
beyond the air that surrounds the earth, let us imagine that we have
fitted out the air-tight cabin of our machine with plenty of air to
breathe, and with food and everything we need for living. We shall
picture it something like the cabin of an ocean steamer. And let us
pretend that we have just arrived at the place where things weigh
nothing:

When you try to walk, you glide toward the ceiling of the cabin and
do not stop before your head bumps against it. If you push on the
ceiling, you float back toward the floor. But you cannot tell whether
the floor is above or below, because you have no idea as to which way
is up and which way is down.

As a matter of fact there is no up or down. You discover this quickly
enough when you try to pour a glass of water. You do not know where
to hold the glass or where to hold the pitcher. No matter how you hold
them, the water will not pour--point the top of the pitcher toward the
ceiling, or the floor, or the wall, it makes no difference. Finally
you have to put your hand into the pitcher and pull the water out.
It comes. Not a drop runs between your fingers--which way can it run,
since there is no down? The big lump of water stays right on your
hand. This surprises you so much that you let go of the pitcher. Never
mind; the pitcher stays poised in mid-air. But how are you going
to get a drink? It does not seem reasonable to try to drink a large
_lump_ of water. Yet when you hold the lump to your lips and suck it
you can draw the water into your mouth, and it is as wet as ever; then
you can force it on down to (or rather _toward_) your throat with your
tongue. Still you have left in your hand a big piece of water that
will not flow off. You throw it away, and it sails through the air of
the cabin in a straight line until it splashes against the wall. It
wets the wall as much as water on the earth would, but it does not run
off. It sticks there, like a s