“It’s… Earth!”
The US president drew back his finger. The blue sphere in the sky was now growing at a rate visible without a reference object, and was now at least three times the diameter of the moon. At first, it looked like a balloon rapidly inflating in the sky, but then a shout from the crowd abruptly changed that impression:
“It’s falling!”
The shout provided a reasonable interpretation of the scene before them. Regardless of its accuracy, they immediately had a new sense of what was happening: another Earth was crashing toward them in space! The approaching blue planet now occupied a third of the sky, and surface details could be made out: brown continents covered in mountain wrinkles, cloud coverage looking like unmelted snow, outlined in black from the shadows cast on the ground. There was white at the North Pole, parts of which glittered—ice, rather than clouds. On a blue ocean, a snow-white object spiraled lazily with the delicate beauty of a velvet flower in a blue crystal vase—a newborn hurricane…. But when the huge blue sphere grew to cover half the sky, their perception experienced an almost simultaneous transformation.
“God! We’re falling!”
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.
It shouldn’t have been difficult for Endeavor’s astronauts to obtain preliminary data, since an astronomer and a space physicist were on board and had all the necessary equipment available and at their disposal, including the ISS, to conduct observations; however, their momentary panic had nearly sent the orbiter to its doom. The ISS was a fully-equipped observation platform, but its orbit was not conducive to observing an object situated 450 kilometers above the North Pole nearly perpendicular to the Earth’s axis. Endeavor’s orbit sent it over the poles so it could carry out observations of the ozone holes; at a height of 280 kilometers, it was flying right between the Earth and the mirror.
Flying with an Earth on either side was nightmarish, like speeding along a canyon with blue cliffs towering above them. The pilot insisted it was a mirage, like the spatial disorientation he had experienced twice during his three thousand hours in a fighter jet, but the commander was convinced there really were two Earths. He ordered their orbit adjusted to compensate for the gravitational pull of the second one, but the astronomer stopped him in time. Once they got over their initial shock and learned from observations of the shuttle’s orbit that one of the two Earths had no mass, they let out a sigh of relief: if they had made the compensational adjustments, Endeavor would be nothing more than a shooting star over the North Pole.
The astronauts carefully observed the massless Earth. Visual inspection indicated the orbiter was much farther away from it, but its North Pole seemed little different from that of the nearer Earth, if not entirely identical. They saw laser beams emitting from both North Poles, two long, dark red snakes twisting slowly in identical shapes at identical positions. Eventually they discovered one thing that the nearer Earth did not have: an object in flight above the massless Earth. Visually they judged it to be in an orbit roughly three hundred kilometers above its surface, but when they attempted to probe its orbit more precisely using shipboard radar, the radar seemed to bounce back from a solid wall a hundred-odd kilometers away. The massless Earth and the flying object were on the opposite side of that wall. Observing the object through the cockpit window using high-powered binoculars, the commander saw another space shuttle flying in low orbit over the frozen Arctic ice pack like a moth crawling along a blue striped wall. There was a figure behind that shuttle’s cockpit window, looking through binoculars. The commander waved, and the figure waved at the same time.
And so they discovered the mirror.
They altered course to draw closer to the mirror. At a distance of three kilometers, the astronauts could see clearly Endeavor’s reflection six kilometers away, the glow of its aft engines lending it the form of a creeping firefly.
One astronaut took a spacewalk for humanity’s first close encounter with the mirror. Thrusters on the suit spurted streams of white, speeding him across the distance. Carefully, he adjusted the jets to bring himself into position ten meters from the mirror. His reflection was remarkably clear, without any distortion. Since he was in orbit but the mirror was stationary with respect to the Earth, he had a relative speed of ten kilometers per second. He was racing past it, but no motion at all was visible. It was the smoothest, shiniest surface in the universe.
When the astronaut decelerated, his thruster jets had been aimed at the mirror for an extended period, and a white fog of benzene propellant had drifted toward it. During previous space walks, whenever the fog had come into contact with the shuttle or the outside wall of the ISS, it would leave a conspicuous smudge; he imagined it would be the same with the mirror, except that with the high relative velocity, the smudge would be a long stripe, like he used to draw with soap on the bathroom mirror as a child. But he saw nothing. The fog vanished upon contact with the mirror, whose surface remained bright as ever.