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.

The shuttle’s orbital trajectory gave them only a limited amount of time near the mirror, prompting the astronaut to act quickly. In an almost unconscious act the moment the fog disappeared, he took a wrench out of his tool bag and tossed it at the mirror, but once it left his hand, he and the astronauts aboard the shuttle were paralyzed with the realization that the relative velocity between it and the mirror gave it the force of a bomb. In terror they watched the wrench tumble toward the mirror and had a vision of the spiderweb fractures that in just moments would spread like lightning across the surface from the point of impact, and then the enormous mirror shattering into billions of glittering fragments, a sea of silver in the blackness of space…. But when the wrench touched the surface it vanished without a trace, and the mirror remained as smooth as before.

It actually wasn’t hard to see that the mirror was massless, not a physical body, since floating motionless over Earth’s North Pole would be impossible otherwise. (It might be more accurate to state, given their relative sizes, that the Earth was floating in the middle of the mirror.) Rather than a physical entity, the mirror was a field of some sort. Contact with the fog and the wrench proved that.