“Spewed up from below, I suppose,” suggested the physicist Padilla. “Should heavy elements not have sunk to form a core?”
“No,” answered Verwoort. “They exist, yes, and they would be more plentiful in lower layers, but with as vast a mass of hydrogen and helium as this, the percentage is so small that it must always have been diffused. The core is metallic hydrogen, maybe pressed into a still denser form than in Jupiter. This upwelling should tell us much about the gaseous atmosphere.”
“It is not the only peculiar chemistry,” Takata said. “Jens will have plenty to consider when he gets back.”
“What will we see when the whole thing breaks apart, before it falls into the sun?” asked the steward Hauptmann. While he was intelligent enough, science was not his forte, and with as many people to look after as there were on this voyage, he had been too busy to keep track.
Kivi shook her head. “It won't break like a melon,” she explained. “The planet's self-gravity will hold it together as it fills its Roche lobe. We can't predict events with any precision, and no doubt we will be surprised. However, we can say that turbulence within may well eject great gouts of material, forming a spiral that streams into the star. The magnetic effects—but that goes too far into speculation. Eventually the planet will take a teardrop shape, filling its Roche lobe, and pouring its substance down that spiral until it becomes an accretion disk. This will go on at an accelerating rate for some undetermined time. Decades at least, possibly centuries.” She sighed. “How I wish we had probes that could observe from sunside!”
A goodly number were aflight, but those that had gone between planet and star were suicides, sending only bare glimpses before heat and radiation killed their electronics. Tyra's mind strayed for a moment to an image she had seen two daywatches ago. Samurai's long-range observations had, earlier, picked up a craft that emerged from Strong Runner and went out to the ice moon of Three. Now it had returned, presumably loaded. Spheroidal, with broad fins, blinding-bright reflective, it was of a size to account for the mother ship apparently having only three other boats along in spite of being designed as a carrier. The view that Samurai's computer reconstructed and shared with Freuchen showed it maneuvering about, a test run. Spectroscopy revealed it venting some water vapor from widely over its surface.
Craig Raden had been with her then, gazing as intently. “A sundiver for certain,” she had said. “Not nearly as big as the one Captain Saxtorph encountered, and probably not as well outfitted. It can't have life support for more than one or two. A prototype, pressed into service.”
“You seem to have studied the subject rather thoroughly,” he drawled. She felt how she flushed.
“Naturally, after I'd been with Rover's people, I was interested in their past experiences and went back to the database entries.” Was he watching her? She didn't look toward him.
“For an opportunity like this, they'll take the risk. A bold venture, ingeniously thought out, and very possibly scientifically invaluable. We must find our way to cooperation with them.”
She made no reply. Worse than useless, reviving that quarrel. He had likewise been careful after the crisis to say merely that Bihari could have shown more restraint. After all, Emil, Louise, and Birgit were back among them, uninjured albeit shaken. Once again, though, the relationship between Tyra and Craig was not quite cordial. That hurt worse than she cared to admit.
Kumukahi's image was slipping close to Pele's in its headlong rush around the sun.
“The polar orbiters are doing fine work,” Takata was saying.
“At a distance,” Kivi answered. “If we had had time to design and build a sundiver of our own—”
“We didn't,” snorted Verwoort. “We can recommend the making and dispatching of several when we report home.”
“Robots,” said mate Deutsch a bit sadly. “Nothing but robots to keep watch after us.”
“Well,” replied Captain Worning, “decades or centuries would be a long and expensive time to maintain humans on station. They might grow bored.”
Padilla laughed. “Besides,” he put in, “when enough atmosphere is gone that the core drops below a critical threshold, it will explode. I would not want to be any closer than hyperspace escape distance.”
“Yes,” agreed engineer Koch, “better we live to see the images.” Kumukahi dropped below yonder restless horizon.
“Let us check with the boat,” proposed Worning, and entered a command. Tyra's heart stumbled.
Josef Brandt was piloting for physical chemist Jens Lillebro. Raden had invited himself along. “Not my cup of tea, strictly speaking,” he had said with his irresistible smile. “But one never knows what sort of clue lies where, does one? At least I can take a few observations of Pele from that angle. Those spots on her are acting downright eerily,” as the planet's gravitational force swept through the photosphere.
The screen in Freuchen awoke again, to a view of Henrietta Leavitt's cabin. Brandt sat intent at his controls, Lillebro at his spectroscopic readouts. Raden saw that they were in communication and responded. “All's well,” he proclaimed. “We're closing in on the asteroid, and will have velocities matched quite shortly, at about five klicks' distance. Behold.”
No time lag was noticeable. They were only some 15,000 kilometers away. Kivi had identified the body among the data pouring in from the continuous automatic skyscan and, retrieving earlier information, computed an orbit. Now they saw a rough gray lump, about three kilometers long and one at maximum thickness, slowly tumbling.
“Apparently chondritic,” commented Raden. “You'll notice the remarkable sparsity of craters. You're right, Maria, it must be from the outer belt, lately perturbed into an eccentric path.”
Pristine, Tyra knew, formed hardly more than a billion years ago, in a thinly bestrewn region where there had been scant occasion or time for collisions. Probes were to examine such rocks later. But who knew how much later? Composition and structure might well give unique insights into the early life of every planetary system. This chance was too good to pass up. Should Kumukahi make sudden call on Henrietta, she could boost back to Freuchen in well under an hour.
“Backing down on it, essentially,” continued Raden's voice. The asteroid swelled fast in sight. “As you recall, we'll run parallel and let Jens stare while we send minisamplers—”
The thing erupted. A white cloud burst raggedly forth. Gravel and boulders sleeted outward.
Tyra heard herself scream.
The view swung wildly. The barrage became glints across a whirl of stars. Somebody in the boat yelled, “Almächtige Gott!” Somebody else ripped an oath. The view returned to the cabin and steadied on Rader. Sweat studded his brow, but he grinned, well-nigh laughed. “Whoop, that was close! Thank Josef here. The autopilot isn't programmed for— He yanked us free. Barely, but he did it.” Brandt looked around, his own expression grim. “Barely is correct,” he grated. “Some of those stones could have holed us, or even been bouncers.” Tyra shuddered. She knew what he meant. The boat lacked a protective screenfield. The hull was self-sealing. But a small object that punched through could lose too much energy thereby to make an exit, not too much to ricochet back and forth and quite likely hit a man.
“Was für den Teufel—what happened?” roared Worning.
Lillebro spoke almost calmly. “I can guess. The chondrules surrounded a mixture of ices, which also mortared them together. The agglomerate was metastable, and the impulses from our polarizer drive as we neared touched off volatilization and—it will be fascinating to learn what reactions.”
“A bomb,” added Raden. “I daresay they're not uncommon in young systems, but all of them are disrupted—solar input, impact energy, perhaps cumulative cosmic ray effects—long before intelligence evolves locally to notice them. What a discovery!”