Within a month, the remnants of Ymir had all been consumed, and Izzy had seemingly ceased to exist. The two of them had merged into an orbiting mountain. Its summit was a battered and scarified lump of nickel-iron, hazy with angular scaffolding where antennas and sensors were mounted. Its slopes were a smooth rampart of black ice, interrupted here and there by outcroppings of thrusters or other equipment, observation domes peeking out like hermits’ huts. Its base was a plane decorated with a neat grid of eighty-one small holes from which blue-white fire erupted from time to time as the ship passed through her perigee.