Chapter 10

B1 & B2 each had around 8 septillion kilograms of mass, and a radius of 7.4 million meters. The surface gravity was barely less than Earth’s. The problem was that 5000km of atmosphere. 300km down I was expecting the atmospheric air pressure to be 1 bar, but the temperature was still sub zero.

“The problem with a thick atmosphere, is that it’s going to be very cold except near the surface where water vapor allows it to warm. Water vapor likely won’t extend more than 5km up, so the clouds we see are all low altitude clouds,” Odin explained.

“What actual atmospheric pressure are we dealing with on the surface?” I asked.

“Back of the envelope calculation says that the pressure should be turning the ocean into steam. That’s not happening here, so I’m guessing that the atmosphere density is lower, somehow.”

“My atmospheric probes have been falling for 10 minutes, and I don’t have a pressure reading yet. I’m not even detecting atmosphere.” Tyr said.

“I’m holding position directly over the probes,” I told him, “I’m exactly 6000km from the surface, and your probe is 1650km from me. I conjured it 500km from me to give it time to gather speed and reboot.”

There was silence as several people tried to do the math. “Atmospheric pressure is not linear, but are you sure that 5000km is how deep the atmosphere is?”

“That’s the distance that it starts feeling thick to my power,” I checked on Earth, focusing up, “Oops. I’m getting that same level of thickness at about 4500km up from Earth. I guess I’m just more sensitive than I expected.”

“Well that changes everything!” Mithra said heatedly.

“500km up for a floating city, or I remove 500km of atmosphere.”

“Whatever you do, don’t do that last one without talking to me first,” Mithra warned.

“Why?”

“It would probably kill everything on the planet, as all the dissolved gases in the ocean would bubble out like a shaken coke bottle being opened with the loss of pressure.”

“Ok, I’ll talk to you before any terraforming.”

“What we need is a biologist. Preferably a xenobiologist.”

“I think those are only theoretical.”

“Not any more!” Val responded as she looked at a sample held in a diamond container thru a microscope. “It’s dividing, so definitely alive.”

“That’s just the single celled algae. I’m seeing lots of invertebrate life, including a cool colony of septopods on B1. B2 has vertebrates, there’s this manta ray like creature that’s just awesome.”

“You have actual sea creatures, and you just gave me microscopic life to examine?” she said indignantly.

“I haven’t forged containers for them yet. They are under lots of pressure, I have to conjure the container around them, then absorb and conjure the container somewhere safe. I can’t do it on Earth, so I’m building a zoo of sorts on the surface of Proxib, but about 1500 meters underground where it’s warm.”

“Wait, are you saying that B1 and B2 has an atmosphere only 500km thicker than Earth, not 4700km like we thought?”

“It’s still in the sextillions of kilo Pascals.”

“If your estimate of the top is accurate. Technically Earth’s atmosphere extends past the moon.”

“How about I just conjure a probe to the surface, and we see what the pressure is.”

“Yes! Do that!”

So I did, and Tyr looked carefully at the results as it rebooted. “I’m reading 11,120 kPa.”

There was a pause as they did the math, “That’s a 110 atmospheres of pressure.”

“Not liveable right?” I asked.

“Very much not liveable. But we have our answer, it’s the equivalent of 50km thicker than Earth’s.”

“Sounding better for an aerial floating city. Should I go ahead and start building?” I asked.

“What are you thinking shape wise?”

“A giant ring, like an inner tube, made out of Barkley Paper. Evacuated of air it will hold the city up. The city will hang from it, with buildings longer in the middle, and shorter at the edges, with open park space across the upper surface.”

“Sounds pretty, how big?”

“Fifty kilometers across sounds good.”

“That’s a big upside down mountain. With that amount of living space where will the people get their food? They can’t go to the surface to fish.”

“They can grow food in the reverse skyscrapers, or on the park above.”

“We aren’t detecting any clouds above 15km, so the city will never get any rain. It might also be very cold at that altitude without water vapor.”

“I guess I need to fly down and check it out.” I told him.

“Before you do that, can you get pictures of the creatures?”

“Probably not without removing them first. I’m worried that it’ll be the same as the deep water creatures of Earth, they die the moment they are brought to the surface as their bodies explode when not under pressure.”

“Wait a minute, to which planet was that probe sent to the surface?”

“That was B1.”

“Can you do B2 now?”

“Sure,” I said as I conjured.

“1060 kilo Pascals!” he shouted excitedly.

“That’s only 25km thicker!”

“That’s 10 atmospheres at the surface of the water.”

“B2 has the vertebrates right?”

“That’s right.”

“That’s why, the pressure is less, so vertebrates can survive.”

“Oh that’s so cool!” I said, “The Mantas just chased a school of fish to the surface, and they flew away.”

“There are flying fish?”

“Apparently!” I confirmed.

“How livable is 10 atmospheres?”

“It would be ok in a hardsuit like deep water divers use.”

“Plenty of oxygen, but the suit would have to reduce its pressure before letting you breathe it.”

“What about a merman/mermaid body modification? Could you adjust a twin so that it could breathe like a fish?”

“Your thinking adjust the human to the environment instead of the environment to the human?” I asked.

“Sure, plenty of sci-fi stories about that being the solution to colonization.”

“Just how deep is the ocean?” Val asked.

“The shallowest spot I’ve found is about a kilometer deep. It’s an underwater volcano, but not currently active.”

“Does that answer the question of being tidally locked?”

“It does, and they are. They are also exchanging atmosphere molecules, and probably have exchanged single celled life as well.”