Forrester was grinning his cherubic smile. “That’s probably why it’s so bright already. Some of the gases are interacting. Think what we’ll see when they really get to boiling near the Sun! Ook ook.”
Sharps was getting that thoughtful, lost look again. Harvey said quickly, “Dr. Sharps—”
“Oh. Yes, certainly. What happens if it hits? Which it won’t.
Well, what makes the nucleus dangerous is that it’s big, and it’s coming fast. Enormous energies.”
“Because of the rocks?” Harvey asked. Rocks he could understand. “How big are those rocks?”
“Not very,” Forrester said. “But that’s theory—”
“Right.” Sharps was aware of the camera again. “That’s why we need the probe. We don’t know. But I’d guess the rocks are small, from the size of a baseball to the size of a small hill.”
Harvey felt relief. That couldn’t be dangerous. A small hill?
“But of course that doesn’t matter,” Sharps said. “They’ll be embedded in the frozen gases and water ice. It would all hit as several solid masses. Not as a lot of little chunks.”
Harvey paused to think that over. This film would take careful editing. “It still doesn’t sound dangerous. Even nickel-iron meteors usually burn out long before they hit the ground. In fact, in all history there’s only been one recorded case of anyone being harmed by a meteor.”
“Sure, that lady in Alabama,” Forrester said. “It got her picture in Life. Wow, that was the biggest bruise I ever saw. Wasn’t there a lawsuit? Her landlady said it was her meteor because it ended up in her basement.”
Harvey said, “Look. Hamner-Brown will hit atmosphere a lot harder than any normal meteorite, and it’s mostly ice. The masses will burn faster, won’t they?”
He saw two shaking heads: a thin face wearing insectile glasses, and a thick bushy beard above thick glasses. And over against the wall Mark was shaking his head too. Sharps said, “They’d bore through quicker. When the mass is above a certain size, it stops being important whether Earth has an atmosphere or not.”
“Except to us,” Forrester said, deadpan.
Sharps paused a second, then laughed. Politely, Harvey thought, but it was done carefully. Sharps took pains to avoid offending Forrester. “What we need is a good analogy. Um…” Sharps’s brow furrowed.
“Hot fudge sundae,” said Forrester.
“Hah?”
Forrester’s grin was wide through his beard. “A cubic mile of hot fudge sundae. Cometary speeds.”
Sharps’s eyes lit up. “I like it! Let’s hit Earth with a cubic mile of hot fudge sundae.”
Lord God, they’ve gone bonkers, Harvey thought. The two men raced each other to the blackboard. Sharps began to draw. “Okay. Hot fudge sundae. Let’s see: We’ll put the vanilla ice cream in the center with a layer of fudge over it…”
He ignored the strangled sound behind him. Tim Hamner hadn’t said a word during the whole interview. Now he was doubled over, holding himself, trying to hold in the laughter. He looked up, choked, got his face straight, said, “I can’t stand it!” and brayed like a jackass. “My comet! A cubic mile of hot… fudge… sun… dae…”
“With the fudge as the outer shell,” Forrester amplified, “so the fudge will heat up when the Hammer rounds the Sun.”
“That’s Hamner-Brown,” Tim said, straight-faced.
“No, my child, that’s a cubic mile of hot fudge sundae. And the ice cream will still be frozen inside the shell,” said Sharps.
Harvey said, “But you forgot the—”
“We put the cherry at one pole and say that pole was in shadow at perihelion.” Sharps sketched to show that when the comet rounded the Sun, the cherry at the oblate spheroid’s axis would be on the side away from Sol. “We don’t want it scorched. And we’ll put crushed nuts all through it, to represent rocks. Say a two-hundred-foot cherry?”
“Carried by the Royal Canadian Air Force,” Mark said.
“Stan Freberg! Right!” Forrester whooped. “Shhhh… plop! Let’s see you do that on television!”
“And now, as the comet rounds the Sun, trailing a luminous froth of fake whipped cream, and aims itself down our throats… Dan, what’s the density of vanilla ice cream?”
Forrester shrugged. “It floats. Say two-thirds.”
“Right. Point six six six it is.” Sharps seized a pocket calculator from the desk and punched frantically. “I love these things. Used to use slide rules. Never could figure out where the decimal point went.
“A cubic mile to play with. Five thousand two hundred and eighty feet, times twelve for inches, times two point five four for centimeters, cube that… We have two point seven seven six times ten to the fifteenth cubic centimeters of vanilla ice cream. It would take a while to eat it all. Times the density, and lo, we have about two times ten to the fifteenth grams. Couple of billion tons. Now for the fudge…” Sharps punched away.
Happy as a clam, Harvey thought. A very voluble clam equipped with Texas Instruments’ latest pocket marvel.
“What do you like for the density of hot fudge?” Sharps asked.
“Call it point nine,” Forrester said.
“Haven’t any of you made fudge?” Charlene demanded. “It doesn’t float. You test it by dripping it into a cup of cold water. Or at least my mother did.”
“Say one point two, then,” Forrester said.
“Another billion and a half tons of hot fudge,” Sharps said. Behind him Hamner made more strangled noises.
“I think we can ignore the rocks,” Sharps said. “Do you see why, now?”
“Lord God, yes,” Harvey said. He looked at the camera with a start. “Uh, yes, Dr. Sharps, it certainly makes sense to ignore the rocks.”
“You’re not going to show this, are you?” Tim Hamner sounded indignant.
“You’re saying no?” Harvey asked.
“No… no…” Hamner doubled over and giggled.
’Now, she’s coming at cometary speeds. Fast. Let’s see, parabolic speed at Earth orbit is what, Dan?”
“Twenty-nine point seven kilometers per second. Times square root of two.”
“Forty-two kilometers a second,” Sharps announced. “And we’ve got Earth’s orbital velocity to add. Depends on the geometry of the strike. Shall we say fifty kilometers a second as a reasonable closing velocity?”
“Sounds good,” Forrester said. “Meteors go from twenty to maybe seventy. It’s reasonable.”
“Right. Call it fifty. Square that, times a half. Times mass in grams. Bit over two times ten to the twenty-eight ergs. That’s for the vanilla ice cream. Now we can figure that most of the hot fudge boiled away, but understand, Harvey, at those speeds we’re just not in the atmosphere very long. If we come in straight it’s two seconds flat! Anyway, whatever mass you burn up, a lot of the energy just gets transferred to the earth’s heat balance. That’s a spectacular explosion all by itself. We’ll figure twenty percent of the hot-fudge energy transfers to Earth, and” — more buttons pressed, and dramatic rise in voice — “our grand total is two point seven times ten to the twenty-eighth ergs. Okay, that’s your strike.”
“Doesn’t mean much to me,” Harvey said. “It sounds like a big number…”
“One followed by twenty-eight zeros,” Mark muttered.
“Six hundred and forty thousand megatons, near enough,” Dan Forrester said gently. “It is a big number.”
“Good God, pasteurized planet,” Mark said.
“Not quite.” Forrester had his own calculator out of the belt case. “About three thousand Krakatoas. Or three hundred Thera explosions, if they’re right about Thera.”
“Thera?” Harvey asked.
“Volcano in the Mediterranean,” Mark said. “Bronze Age. Where the Atlantis legend comes from.”