He raised his face to the red orb whose heat scarcely touched here. Again he marvelled that disaster had come so suddenly. Solar radiation was not supposed to end like that! It should have gone on for millennia. That's what the scientists had preached. But it had ended—scarcely five hundred years ago. Curt had never known Earth, only the city here far within Mercury, where there was meager warmth and light. And now even the internal heat of Mercury was fast cooling.
Curt turned at the sound of footsteps behind him. That would be Olana. She, too, came here each week.
She stopped beside him, raised her helmeted face to Sun and stars with infinite longing. For a moment neither of them spoke. Then Olana clicked on her helmet radio.
"Each time, Curt ... each time I come here I imagine the Sun has grown dimmer. Is it really only my imagination?"
"Yes. It becomes dimmer, but not perceptibly. Solar radiation is electronic, and the theory is that our Sun has merely exhausted an outer sheath of electrons. Lord knows what internal condition caused it! If it's a solid body, it may be due to certain peculiarities of the strata. The sun spots of hundreds of years ago must have been the beginning of the end."
She nodded. "How is the work coming?"
"The Traction Rays? Slowly, Olana—too slowly." Curt shook his head in weariness. "We're in the process of testing, but they are still not strong enough. It means months more of work, and we shall need hundreds! You know, if we fail on the first attempt we shall not have another chance."
"I—I still don't quite understand it," Olana was puzzled. "I know it has something to do with the orbit of Vulcan. But how can it save us?"
"It may not. It's a forlorn chance. You know of course that Vulcan's a very small planet, scarcely larger than Earth's moon. And it pursues an orbit much closer to the Sun than Mercury. If we can drive it out of its orbit with the Traction Rays, it may fall into the Sun!"
"But suppose," Olana pointed out, "it only takes up a closer orbit?"