Ever since the world stopped spinning, my brother has kept a tight grip on the net of the tennis court. Though the remaining scientists tell us it is impossible, he believes the earth will start rotating once again, at which point he fears he will be hurled off, just like his tennis partner Cynthia Childers was back when the earth first stood still.

She shot into the sky like a perfect serve because of inertia, I try to explain. I tell him that even if somehow the world began to rotate again, it would start slowly, like a car. Bad example. Gregory moans, and we reminisce about the time he was five and he snuck on top of Dad's car, and Dad didn't see him and put the car in reverse. He was lucky that time, too: he landed on a pile of Pink Panther insulation that was in the garage between our parents' Volvos.

Gregory was lucky this time because he was volleying close to the net when the earth stopped, and the rotational cessation flung him into its tight embrace. He should be thankful to me for teaching him to play close to the net like that. Instead, he is mad at me because he remembers when he was seven and I told him that the earth would never stop spinning.

It had always been his greatest fear.

- - -

He is ten now. He was nine when the earth stopped, on the day before his tenth birthday. I think that makes him angry, and even less inclined to let go of the net, that so many people were tossed into oblivion just before his big double-digit day. A week after his birthday, some of the other survivors and I tried to bake him a cake, but we couldn't find enough eggs that weren't broken, and he was crying so hard that it would have been pointless to get him any presents, since he wouldn't have seen them through the tears.

I try to keep his spirits up. I tell him that our parents and everyone else who was flung off are living happily in outer space. I tell him it just so happens that the sky is a mirror of everything on earth—but not like a regular mirror, because the sky never forgets images of anything that ever existed—and so our parents are living in a house in the sky identical to the one we used to have. He doesn't believe me, of course, and I guess he shouldn't, but it kind of ticks me off that he doesn't even pretend.

I used to tell him they were living happily on the moon, in castles made of moon-sand, and that for dessert after every meal they ate moon-cream, all the moon-cream that they could ever want to eat, in thousands of different flavors. Moon-cream, I told him, was the moon-version of ice cream. I told him the moon had udders that stuck out of the sand, which industrious post-earthlings milked. He liked this story.

Then, the day before Christmas, the moon's orbit collapsed, and it sank into the sun.

- - -

Whenever I see a scientist strolling through our weed-thickening garden, examining plants because that's all there is for scientists to do nowadays, I ask about my own childhood fear. The seasons no longer exist, which I guess is good because I never liked winter, and I guess we're lucky that things stopped during spring and every day is seventy degrees, but lately I've started to worry that the earth is losing its gravity.

When I was little, I used to think about that, about gravity reversing itself. Everyone floating away, with hours to ponder and panic before they reached the atmosphere's end. Millions of people drifting into a once-blank sky, balloons filled with regret. The other survivors and I, perched in topsy-turvy forests, or looking out the windows of upturned buildings, would avert our eyes, so the doomed wouldn't feel embarrassed to have been caught outdoors. Much of my childhood was spent beneath trees and under doorways.

Even now, I feel an affinity for the shade, and I credit this fear-ingrained habit for saving my life: the day the earth stopped, while I was watching Gregory and his doomed paramour Cynthia Childers play kiddie tennis, I was sitting beneath a firm-limbed oak that had surprisingly gentle branches.

When I ask my gravity question, the scientist gets all serious, and if he's a male scientist, he begins to stroke his beard, which all the male scientists now have. Then he'll adjusts his eyeglasses (they all wear spectacles now, male and female, even those with good eyesight), and say something to sound thoughtful, like, "Well, gravity, that all depends." Then he'll start reciting useless facts about terminal velocity and the mass of the earth's core. When I get tired of waiting for a real answer, I ask what he thinks is going to happen next, and that always gets him. It's like asking someone how come they weren't thrown off. You just don't do it.

As a child, I also used to be the tiniest bit scared all the pens and knives and sharp things in the world were going to shoot off in the direction they were pointing, like rockets at the speed of light. Like the end of inertia. And I wouldn't be able to get out of the way in time, so I always made sure I wasn't standing in the path of anything sharp. This was easy for me to do with just the pens in my room, until I started thinking about millions of sticks and pins and knives crisscrossing the globe, trapping everyone in a web of danger. But I've moved on from that fear. I am pretty sure it will never actually happen.

- - -

If the earth were still moving, it would be getting dark now. It's tough to tell when it's night; you can go by when you're feeling sleepy, but maybe you're just exhausted from scavenging. I close my eyes and pretend that everything's the way it used to be, and then I head toward my tent, which I recently fastened to the oak tree with thick rope that I bartered for. Just as a precaution. Just in case gravity does stop and I start to drift away while I'm asleep.

I peer out through the flaps and watch Gregory, who is clutching the net with only one hand now. With his free hand, he is spinning a pinwheel that I stuck into the grass at the edge of the court. It spins merrily, like pinwheels always have and probably always will, and I smile at him. He turns away and punches the ground.

I worry about Gregory sometimes. He's outdoors, I guess, but I'm not sure this is the healthiest way for him to spend his childhood.