A glowing yellow cylinder of translucent plastic slid down over them. This was just a guide to keep them inside the LMT field; they were safe so long as they stayed a couple of centimeters from the plastic. Anything not inside the field when the current pulse came would simply be left behind. It didn’t have to be an arm or a leg; just a little piece of the suit would be more than enough.
“Ninety seconds.” Nobody said anything. “Thirty seconds.”
“Hot or cold?” Vivian said. “Any bets?”
“Bet you a dollar it’ll be just like Earth,” Carol said. “But you’ll have to give me a thousand to one. Ten thousand.”
“Yeah,” Jacque said. “Biosphere must be thin as an eggshe-“
6 – Biospheres: Classroom 2041
SCENE: Classroom in an exclusive, old-fashioned private school in upstate New York. Drowsy hot day in late spring, airco broken.
CAST OF CHARACTERS: TEACHER is William J. Gilbert, M.A., this form’s instructor in the physical sciences. He is annoyed at the class’s lack of attention but thinks he has hit upon a device that will liven things up. JACQUE LEFAVRE did not do the previous night’s homework and doesn’t know a biosphere from a bowling ball. Two days before, he has officially dropped the terminal “S” from his name (because he was tired of being called “zhocks”) and, instead of taking notes, he is practicing his new signature. Assorted STUDENTS and one FLY.
TEACHER
Sitting on the desk-trying not to seem stiff.
I think that the text’s explanation of the biosphere is rather obscure.
Gets off the desk, stiffly.
Do you agree, Mary?
FIRST STUDENT
Yes, sir. But I think I understood it.
SECOND STUDENT
Whispers to Third STUDENT:
Jesus, what a brown-nose.
TEACHER
Did you have something to say, Ronald?
SECOND STUDENT
No, sir. Just that I think I understood it, too.
Class reacts predictably.
TEACHER
You have no idea how happy that makes me.
Reaches in drawer and brings out a navel orange.
Perhaps a demonstration will make it equally clear to everybody.
Produces pocket knife and opens it with a flourish.
How many people have had calculus and analytic geometry?
Only three hands go up as he carefully cuts through the skin and rind, making a circle around the middle of the orange.
Very well, then. I won’t call this a locus.
He twists and worries at the orange until he has three pieces: the fruit and two hemispheres. He sets the fruit aside.
These two halves of the skin and rind will be our biosphere model.
He puts the two hemispheres together.
Imagine, if you will, that there is a tiny star in the center of this sphere.
He sets down one half and points to the inside of the other with a pencil.
Since the star is in the center, any point on this rind is going to be the same distance from the star. Thus, every point on the rind will get the same amount of energy from the star, and will be at the same temperature.
Taps the outside.
Likewise with the skin. Same distance all around, same temperature. A little cooler than the inside.
FOURTH STUDENT
Inverse square law.
TEACHER
Very good, Stan. But please don’t interrupt..
A FLY has entered the room and is buzzing very loudly, trying to escape through the windowscreen. The TEACHER glances at it for a moment, then continues.
TEACHER
We will say that the temperature of the inside of the rind is a hundred degrees Centigrade, the boiling point of water. The outside skin is where the temperature is zero degrees, the freezing point.
Now, Mary. Will you tell the class what that means?
FIRST STUDENT Quickly:
It means that the only place in the system where you can have liquid water is the volume that corresponds to the rind of the orange.
TEACHER
Very good. What else?
FIRST STUDENT After a moment:
Everywhere else you’ll just have steam and ice?
TEACHER
Looks at the FLY again but decides not to go after it.
That’s true, but it’s not exactly what I’m looking for. Anybody else? Mark?
FOURTH STUDENT
Puts down hand.
Where there’s no liquid water, you can’t have life as we know it. Because carbon-based life needs water…