“She’s a disciple in the cause,” Cavan replied. “If Herbert makes it big-time, she flies high too. I just happen to have a recording of the call. . . .” Keene shook his head but said nothing.
The screen split vertically to show Salio on one side, and a woman speaking in front of a background of bookshelves and part of a window on the other. Showing just his mop of black hair and heavy-rimmed spectacles, with no jeans or cowboy boots to offset the image, Salio looked even more the student than when Keene had met him. Hutchill was probably in her thirties, a little on the plump side with rounded features, and short, unpretentiously cut hair. Her eyes had a sharp look, however, and her voice was firmer than her appearance would have suggested. Keene sensed a potential antagonism being consciously kept under restraint.
“Dr. Salio?”
“Yes.”
“I hope I’m not calling at a bad time. Do you have a few minutes?”
“Not if it’s insurance, siding, or you want to lend me money.”
Hutchill forced a smile. “No, I’m not selling anything. My name is Dr. Hutchill, from the Department of Astronomy at Yale. It’s in connection with the plan to put you on the show with Coast-to-Coast.”
Salio looked more interested. “Well, it’s not exactly firm yet.”
“Yes, I understand that. What I’m concerned with is getting an idea of the probable content to assess its suitability.”
“Oh . . . okay. What would you like to know?”
“Note how she’s giving the impression of being connected with the show as if she’s some kind of official advisor,” Cavan put in from his side of the screen.
“Yes, I did pick that up,” Keene replied.
The conversation opened with a trading of views on theories of the formation and stability of the Solar System. Salio was candid in the way he had been with Keene, maintaining a humorous note and declining to be unduly deferential. Eventually, they closed over the matter of comets originating from Jupiter. Hutchill’s manner became more penetrating. The issue, basically, was whether the shower of new comets that had been born with Athena provided adequate evidence that the previously existing short-period comets—the ones with aphelia showing a statistical clustering at the distance of Jupiter’s orbit—had originated in a similar episode involving Venus. Salio’s answer was, sure they did. You didn’t need the other mechanisms that been speculated about over the years and could throw them away. Hutchill was determined to see them as exceptions.
“There simply aren’t grounds for making such a sweeping generalization on the basis of an event that has been observed only once,” she insisted. “You’re ignoring the transfer of long-period comets to short-period trajectories by perturbation, which is still the dominant process on any significant time scale.”
Salio grinned, evidently having expected it. “That’s what the textbooks say,” he agreed. “But when has it been observed even once? I can point you to a string of papers going back to before 1900 which show that such a mechanism isn’t viable. It’s a myth that has been exposed now for well over a hundred years.”
Displeasure showed through Hutchill’s demeanor for the first time. “I think I’d advise caution before dismissing something that’s so widely accepted,” she said.
“But if acceptance were the thing to go by, then a popular but wrong theory could never be changed,” Salio pointed out. “Let’s try plausibility instead. All the estimates that I’ve seen agree that the probability of Jupiter deflecting incoming comets from vast distances on parabolic orbits to an elliptical one is about one in a hundred thousand. So that’s the ratio of short-period to long-period that you ought to get. In fact what you have is close to sixteen percent. The number of long-periods is far too small. How many comets are there in the Jupiter family—about seventy? And the typical lifetime would be what . . . four thousand years?”
“Hmm. . . . Maybe.”
“Let’s take that figure, then, and suppose that Jupiter has to replenish them by capturing long-period arrivals at the rate of one in a hundred thousand. To give seventy in four thousand years would require seven million long-period arrivals, which works out at seventeen-hundred-fifty a year, or five every day. Allowing for the transit time in and out of the Solar System would give us about nine thousand present in the sky by my calculations, of which let’s say half would be brighter than average. A pretty spectacular sky.” He shrugged and waved a hand, seemingly enjoying himself. “So where are they? And then you’ve got the problem that all of the short-periods orbit the Sun in the same direction as the planets, as they should if they came from Jupiter. But by capture, some should be retrograde—in theory half of them. You see, the numbers just don’t work out.”