Geena was watching in horrified fascination. She didn’t seem able to move out of the way.

The blob hit her square on her chest. The magic of zero G dissipated instantly, and the puke spread out over her white T-shirt, viscous, sticky and lumpy.

She started dabbing at it with wet towels. “Henry, you asshole.”

“I never said I was a spaceman.”

The other lump of vomit reached a locker door now. Instead of sticking, it broke up into a dozen smaller globules, that rebounded and set off over the cabin.

Arkady came floating up from the descent module. “I could smell — oh.” He laughed. “Time to hunt butterflies, I think.”

He took a handful of wet wipes, and he and Geena started to chase over the cabin, snagging the vomit spheroids out of the air. Henry just hung there being still, trying not to worry about which way was up.

Twenty-eight hours out; a hundred and forty thousand miles from home. A day after TLI, they were already more than halfway to the Moon.

Wrapped in a blanket, Henry hung before a window, staring out.

He could see the Earth every once in a while, as it slid past his window. He could tell it was a fat round world, floating in space, much more three-dimensional than the Moon; the huge highlight cast by the sun from the oceans ensured that, as if the Earth was a huge steel ball under a spotlight. Every time the planet came by, it dwindled. He couldn’t see the change if he watched, but if he turned away from it and looked back, it was a little smaller and more distant.

Now, with the planet reduced to the size of a baseball, he found he’d lost his sense of what he was looking at. He was supposed to be a geologist, for Christ’s sake. But the real Earth was no map: it was swathed in cloud, and the countries weren’t colour-coded.

Geena laughed at him when he told her this.

“Start from the beginning,” she said. “What’s that big white patch at the edge? Ice or clouds?”

Henry thought about it. “Looks like ice,” he said. “And if it’s summer in the northern hemisphere, and that patch is in sunlight—”

“It has to be the Arctic.”

“Okay. But how can that be right when it’s at the bottom?”

Geena, reasonably gently, took hold of his longjohns at the hips, and swivelled him around, handling his mass as easily as if he was some inert piece of payload.