The feeling of inversion came in an instant. The sphere filling half the sky gave them a feeling of height, or that the ground beneath their feet had vanished and they were now falling toward the other Earth. Its surface was clearer now, and on the dark side, not far from the shadow line, those with keen eyes could see a faint glowing band: the lights of America’s East Coast cities, their own location in New York a somewhat brighter spot within it. The other planet now filled two-thirds of the sky, and it seemed as if the two Earths would collide. There were screams from the crowd, and many of them shut their eyes.

Then all was still. The Earth overhead was no longer falling (or the ground they stood on was no longer falling toward it). The sphere hung motionless covering two-thirds of the sky, bathing the land in its blue glow.

Now sounds of chaos could be heard from the city, but the occupants of the lawn had the strongest nerves on the planet in unstable situations, so they held back their panic at the nightmarish scene and approached it more quietly.

“It’s a hallucination,” the secretary general said.

“Yes,” the Chinese president said. “If it were real, we’d feel the gravity. And this close to the sea, we’d be drowned by the tide.”

“It’s more than just the tides,” the Russian president said. “The two Earths would be torn to pieces by their mutual attraction.”

“The laws of physics don’t permit two Earths to remain motionless,” the Japanese prime minister said, and, turning to the Chinese president, added, “When that Earth first appeared, you were saying that the stars of the southern hemisphere were in the sky above us. Could the two phenomena be connected?” It was a tacit admission of eavesdropping, but they were past caring at this point.

“Perhaps we’re about to find out,” the US president said. He spoke into a mobile phone; the secretary of state, at his elbow, informed the others that he was speaking with the International Space Station. And so they focused their anticipation on the president, who listened attentively to the phone but said only a few words. Silence reigned on the lawn, where in the blue light of that other Earth they looked like a throng of ghosts. After about two minutes, the president set down the phone, climbed onto a chair, and shouted to the expectant crowd:

“It’s simple. A huge mirror has appeared next to the Earth!”

THE MIRROR

There was no way to describe it other than a huge mirror. Its surface perfectly reflected visual light as well as radar with no energy or image loss. Viewed from the right distance, the Earth would look like a stone on a go board ten billion square kilometers in area.