Jacques’s lovely wife was not that far away. Sandy joined them for the short walk down a deck to their stateroom. Apparently, the Galileo was now in Love Boat configuration. She was in one of the Smart MetalTM transports that had been constructed expressly for the Alwa run. She was supposed to have gone back immediately, but she and her sister ship, the Tycho, had been appropriated, or rather retasked, for this voyage to a strange world. For the moment, the two ships swung around each other and both had expanded to make the boffins more comfortable.
Jacques and Amanda’s quarters were quite comfortable with a cozy sitting room. A large office was accessible through an open arch to the right and a bedroom was to the left behind a door. Jacques offered Sandy a comfortable chair, then settled on the couch with his wife.
“Marie, show us the entrance to the cave and tunnel complex,” he said.
Immediately, a hologram appeared in front of them.
“I’m adjusting the view to make it level with someone walking up to the entrance,” Marie said.
“Good. Now, Admiral, you will note that there doesn’t appear to be anything like a cave here. That rock,” and the view swept to the right and left, then up, “is big. It sheared off of the cliff above and hardly looks like there’s anything more to see,” Jacques said.
“However, if you mosey around to the left, you get a different view.”
Sandy studied the scene as it moved quickly to the left. It would be a rough walk. The hill was steep and there were rocks of various sizes littering the ground. It would be easy to turn an ankle.
Then the view from behind the rock appeared.
“You’ve got a rough overhang,” Jacques pointed out. “It’s about a meter wide, so you could walk up to the cave with no risk of being viewed from orbit. There’s about another meter, so if you needed to haul in something bigger, you could.”
“Where are the rocks? The path is almost smooth,” Sandy observed.
“No rocks here,” Jacques said, with a sparkle in his eyes. “You’d almost think someone had cleared a path. If they did, the overhang has kept the rock falls off. There are a few rocks to the right.”
“In a hundred and ten thousand years, you do get rocks.”
“You do,” Amanda said, her shoes off, her feet under herself and an arm around her husband.
“Now we have the cave. It has been occupied. There’s a fire pit that has recently burned wood. Say one, maybe two years old. This entire cave, the part that has daylight reflected into it, is pretty much all windblown dirt, ash or bone. We think a hundred and ten thousand years ago it was much closer to the bedrock.”
The picture adjusted itself to show a cave with a much larger opening.
“We’ve had nano diggers slip through gaps in the soil all the way down to the bedrock. There are layer after layer of dirt and ash with a few bones tossed in,” Jacques said. “None of the bones are alien. Just their prey. There are a few stone tools, sharp stone chips, arrow and spearheads. It’s pretty much what you’d expect at the normal human prehistory dig back on Earth. Some of our archeologists are dying to get a trowel into that dirt, but the nanos have given us a good picture.
“It’s just dirt all the way down?” Sandy asked.
“Yes, but there’s a clear change at the bottom. The sand down there looks like it’s taken from deep in the mountain. It’s consistent with that rock. Above that layer begins the ash, fine dirt and bones.”
“First occupancy was by something other than a hunter gatherer,” Amanda observed.
“It sure looks like it,” Jacques agreed.
Sandy said nothing. For now she was content to just take it all in and taste the questions.
The view moved further back. It came to a small opening, about two meters across and much less than half a meter high at it’s largest.
“That is all that is left of entrance to the tunnel system. Just a small, dark maw. Nothing there to encourage anyone to slip inside.”
“Do your diggers show evidence of the entrance being widened or raised?” Sandy asked.
“After all this time, it is more likely than not that it was worked, however,” Jacques shrugged.
“Yes. A hundred, maybe a hundred and ten thousand years is a long time,” Sandy said, and found herself musing what the things she possessed would look like in a hundred and ten millennia.
The view moved into the tunnel. It quickly passed into pitch blackness. That only lasted for a second, then the view lit up almost as bright as day.
“Our nanos have now adjusted to the low light,” Marie said.
Sandy studied the walls, floor and overhead. They had clearly been constructed, and well-constructed at that. Yes, there were cracks and some places where the sides or overhead had fallen away, but they were not that many.
The nano paused to look down. There was a thick layer of fine dirt on the deck.
“The dust in here is an interesting mixture of concrete from the walls, some wood, and metals. There may also be some bones, but they’ve vanished into just dust. There’s nothing for us to analyze but the dust left behind.”
To the right and left, side tunnels led to large rooms.
“The dirt or dust in these rooms closest to the mouth are rich in iron with some copper. Whatever was here, it’s rusted or eroded away to nothing. Some of us think there may have been electric generators here, but we’re just guessing.”
“It seems logical,” Sandy said. “If this is a high-class thieves’ hole-in-the-wall, or a secret rebel base, you’d put your generators up here so the exhaust could be vented outside.”
“The next batch of rooms are also high in metals, though there are quite a bit of heavy metals mixed in,” Jacques said. “I’ve talked our results over with the head of our Marine detachment. He thinks we might have rusted out guns here with heavy metals in the ammunition. However, again, there’s nothing but dust. The mushrooms, however, are laced with poisonous levels of heavy metals.”
Sandy watched as the view dipped down. The floor was indeed covered with fungi.
“Are there anything like bats or rats in here? If there’s food, there has to be someone eating it.”
Jacques shook his head. “The heavy metal content inside these two rooms and the next two make those fungi deadly. In a hundred thousand years, even the animals have learned this is not a good place to hang out. It may have helped keep this place from going to the dogs, or bears, or bats, or whatever.”
Sandy nodded.
The view continued down the central passageway with other openings into rooms or more passageways leading off into the dark. One large chamber showed ramps heading to an upper and lower level. This place really was huge. When it was occupied, it must have been quite a beehive of activity.
“Where did they get rid of all the rock they chewed up?” Sandy asked.
“I was wondering when you’d ask that. Marie, lets pick up the pace.”
Now, instead of walking through the labyrinth, it was as if they rode a cycle. Openings whizzed by until an end began to loom in front of them. They braked to a sudden stop on a ledge above a precipice.
“Wow,” came from both Sandy and Amanda at the same time.
Before them was a vast cavern. The walls had a phosphorescent glow about them, lighting the huge expanse before them in dim shadows. This was clearly a gift of nature: rough, uneven, and almost limitless. Almost, but not quite. Sandy saw the bottom, far below, and the ceiling way above her. The walls stretched out on either side before vanishing into antechambers.
Several shuttle construction hangars could get lost in here. Far below, shimmered a lake of water that glowed with its own phosphorous light.
“There’s no evidence of human construction here, with one exception.”
Their view tiptoed to the edge of the ledge they seemed to be standing on, then looked over. Below them stretched a massive sand pile.
“We’ve checked the sand. It’s from the same rock we’ve been walking through. They must have had something that could chew up rock and spit out sand. Our guess is that they knew this huge cavern was back here. Say, some spelunker had wiggled his way back here along a natural hole in the rock. They used that cave as a guide to dig the main passageway, then dumped the rest of their residue off this cliff. Off to the left, you’ll see another ledge, less natural. There was likely some elevators there to go below, but they’ve rusted away. Hold on to your stomachs,” Jacques warned, and the view shot down.
Amanda grabbed for her husband with a yelp, then, as the view settled at the bottom, she slugged his shoulder. “That was not nearly enough warning, you brute.”
Sandy had to wait for her own stomach to join her, but her eyes were busy taking in the scene. Yes, there was a huge pile of sand off to her right. Some of it had been scooped out.
“Where’d the sand go?” Sandy asked.
“Someone made a beach down by the lake. Again, the sand is definitely taken from the passageways we just walked through. It does not belong to the lake. Oh, there is something I need to show you.”
Once again, they were speeding by as if on an electro-cycle. They zoomed to the lake, then across the beach of sand to the far side of it. There was a pile of sand, but not very high.
“Absent wind and tides, we think that is just enough sand for a castle,” Jacques said. “Of course, that can only be a guess.”
“Is the beach and the putative sandcastle all you have to show for human occupancy?” Sandy asked.
“Again, we’ve got metals, including heavy and rare earths. But it has all been worn away to the basic atoms.”
“Isn’t plastic supposed to last forever?” Amanda asked.
“They do, or they would unless you had plastic-eating bacteria. One of the things we’ve come across is the residue of just such bacteria. We’ve also found its evolutionary ancestors. Bacteria that have evolved to eat other food now, but still hold the memory in their DNA for eating plastics. Any plastics we leave behind here will likely be eaten up and shit out as hydrocarbons in a couple of thousand years.”
“Why would such a bacterium have evolved on a planet with no plastic to eat?” Amanda asked, slowly.
“Unless there had been plenty of plastic to eat earlier in its history,” Jacques said.
“And someone wanted it to eat any plastic that got left behind here. Someone wanted to erase any sign of the technology that developed,” Sandy added.
“The evidence seems to allow for a reasonable person to reach that conclusion,” Jacques said.
“Jacques,” Marie said. “We have found something that I think you will find interesting.”
“Show us, Marie.”
“We have finished mapping all the tunnels above and natural caverns coming off of this main one. We’ve gone looking for any possible side tunnels. We found one that was blocked by a rock fall. We passed over it and only came back to it when we completed our main mapping effort. We just finished drilling a path through the fallen rocks and we seem to have found something of interest.”
Their view hurried across the cavern, then turned into a side chamber. They quickly zoomed into a natural tunnel that was short, ending at a slide that totally blocked it. Now the view got very restricted as it wiggled through the tiniest of cracks before entering a drilled tunnel and breaking out into the opening. The tunnel continued further back. Beside a huge drop off were what looked like the lenses from a pair of glasses. Whatever had once held the glasses was gone, but the glass remained, unweathered, after even a hundred thousand years or more.
“Glass,” Amanda whispered. “You can eat the plastic, but glass can last forever.”
“If there is nothing to weather it,” Sandy said. “Jacques, what’s the temperature in here?”
“It’s a constant forty degrees. It never warms up. It never cools down.”
“So, the glass never flexes,” Sandy concluded.
“Also, the air on this side of the collapse has a high concentration of CO2. It’s at the lethal level,” Marie told them.
“As if someone had breathed it to the point of suffocation,” Sandy said. “Marie, is there any evidence of who might have breathed it?”
“Just beyond here,” Marie told them, “the cave plunges into a deep well, some two hundred meters deep. The water has almost no oxygen in it. There is something at the bottom. It may just be rocks, but I thought you might want to be here when we get our first view of it.”
“Show us,” Jacques said.
Sandy found tension rising and butterflies roaring in her stomach. She felt like a little girl, staring at a Christmas present she was now allowed to open. She had to force herself to breathe.
The well was pitch dark. The probe plunged down, only the tiny area around it illuminated. It seemed to fall forever with nothing but crystal-clear water to see. Even the walls of the shaft were out of sight, lost to sight beyond the small spark of brightness.
Finally, a large dark object loomed into view.
The light expanded to brighten more area around the probe.
“What is that?” Jacques muttered.
Sandy studied the object. “Ask your probe to cruise around it,” she ordered.
The view did. It showed something spherical, but an edge quickly came into view. The probe cruised along the edge. Beside the hologram they were watching, Marie began to construct a replica of what they were studying.
“It’s a helmet,” Sandy breathed. “And old-fashioned helmet. Just a pot to protect the brain bucket. I bet it’s made of armored plastic.”
It now became clear that the helmet had landed on a ledge.
“Let’s see what’s farther down,” Sandy ordered, and the probe shortened the reach of its beam and began to descend rapidly again.
They found everything they were looking for in a heap on the bottom.