"Geoffrey A. Landis - Turnover" - читать интересную книгу автора (Landis Geoffrey A)

named Turcotte, proposed periodic, catastrophic resurfacing. Every 500 million years or so, the entire
surface of Venus resurfaces all at once. The whole surface of the planet becomes one sin-gle magma
ocean, and all the heat of the interior is released at once. Then, of course, it cools down, and since the
whole thing was molten at the same time, every part of the surface is the same age."
"Well, that makes sense." Percy looked down at the drill controls. "One kilometer, and drilling
steady. So, why don't we like that theory?"
"Because it's a catastrophic theory." Percy looked blank. Charming, but blank. "Catastrophism is
anathema to geologists," Piffelheimer explained. "It smacks of religionтАФthe hand of God wiping the
planet clean. Noah's flood and such. Real geologists are uniformitarians. It's our job to show that the
processes of geology are gradual and continuous." "But if this Turbot theoryтАФ" "Turcotte."
"Turcotte theory was rightтАФ" "But it's not."
"But if it was right, what causes this resurfacing?" Piffelheimer shrugged. The heat builds up.
Eventually something triggers it."
"Two kilometers deep, running steady," Percy said. "How often does it resurface?"
"I told you. It doesn't." She was getting a little annoyed with the conversation, although she couldn't
really blame Percy. After all, his job was to ask innocent questions. Time to change the subject. She
looked around. Nothing but gray, blasted rock under them, uniform gray clouds above them. Between
the gray and the gray was the clear air of the surface. "Have you looked at the horizon?" she asked.
"Notice the way it seems to curve up around us, as if we were at the bot-tom of a shallow bowl."
"Yes, due to the refraction effect from the density gradi-ent of the thick atmosphere," Percy said. "If
the air were clear enough, we would be able to see ourselves on the other side of the planet. We can't of
course, due to Rayleigh scattering. You didn't answer my question. How often, according to Turcotte,
does this resurfacing event on Venus occur?"
"Every 500 million years, give or take," Piffelheimer said, annoyed. She really shouldn't have
answered the ques-tion at all, since Percy was going way beyond his job descrip-tion in pressing it in the
first place, but she was so used to expounding automatically that it didn't occur to her to not answer until
after she already had.
"And how long ago was the last time it happened?"
"Five hundred million years," she said.
"Then there must be a lot of interior heat waiting to get out," Percy said. "What, exactly, triggers the
catastrophic release?"
Piffelheimer shrugged, annoyed. "Anything. An asteroid impact, I suppose might trigger it."
"Or maybe a drill?"
There was no need for Piffelheimer to answer him. The rock surface had suddenly split open at the
site of the drilling, separating into three lines that radiated away from the drill point and streaked for the
horizon. Each of the crevasses split into a network of sidecracks, which instantly fragmented still further.
No doubt there was an ominous thunder accompa-nying the whole process as well, but of course the
insulation muffled that. An orange glow from below lit up the clouds, and the cracks widened until the
magma, welling up from below, washed over them.
Later, as they bobbed in the magma in their coolsuits, Piffelheimer had a perfect opportunity to
expound on the value of perfect thermal insulation, but she decided to stay silent. Kensington probably
knew it all anyway, damn him.
"If you think I'm gonna set my nice clean spaceship down in that," came the voice in her headset,
"you got another thing coming."
She looked up. The expedition transport ship was hover-ing over them. As she watched, a rope
(woven of refractory fibers, no doubt, since it didn't melt in the heat) fell toward them and ploiked down
in the lava next to her. The correct procedure, Piffelheimer knew, is for scientist to carry beautiful
assistant to safety. She glanced over at Percy, floating cheerfully on his back a few meters away, and
decided, screw that. She pulled herself up the rope. Let him pull himself up.
Oh, well. After all, it had been a good day for science, and the scientists' guild ought to be justifiably