The risk of contamination appeared to be low. The Builders seemed content to leave the Ring unguarded, perhaps due to its regenerative abilities. The Island, as it was protected by the graser, was perhaps not capable of self-repair. This was the best working theory the crew had to go on. Although the head of a simple planarian worm will grow back when it is cut off, the same cannot be said of a human. Similarly, it would be much more difficult to outfit the Island—a much more sophisticated construction than the exoskeleton of the Ring—with the capacity to regenerate itself when damaged.
It was likely that the nanomachines responsible for the fabrication and maintenance of the Island were still wandering its surface. Unlike the nanomaterial composing the Ring, the Island’s machines did not go about their work blindly. Aki pictured them emitting and receiving messages for propagation direction control, powered by something beyond human invention and understanding. Perhaps even Maxwell’s Demon had finally been constructed, and the nanobots were harvesting molecular-level power from the minute differences in temperature and energy across the Island’s surface.
“EVA prep completed,” she said.
Before the other two could come to the airlock door to see her off, Aki stepped in, depressurized, and opened the craft’s external door. The stern of the ship was pointed straight at the Ring. A continuous weak blast from the engines of the orbital maneuvering system counteracted the gravitational force of the Ring and the Island, allowing the ship to maintain a constant distance.
Aki was five hundred meters above the surface of the Ring. She held the railing. Her hands would not want to push off. She visualized the process so she would be ready when the moment came. The cliff surrounding the Island soared upward from the surface of the Ring about two kilometers ahead. A graser cannon was perched at the crest of the precipice.
Aki tried to keep from looking in the direction she could not help but think of as “down.” When she finally managed to push off, fear caused her breath to hitch.
“There is a red light on the Ring. It is targeting us.” Aki considered her options, then realized where the mirror-like surface of the Ring was facing. Her red target light was actually a reflection of Alpha Orionis, the red star Betelgeuse. Her sigh of relief echoed inside her helmet. The ship proceeded forward steadily until it was directly above the Island, its floodlight slicing across the top of the graser battery. The Ring’s gray and shiny surface was no longer below her feet. She dangled above what look like the compound eye of an enormous insect. An eye that extended into the distance farther than she could see.
“Starting descent.”
“God bless,” said Commander Kindersley.
Aki pushed herself away from the stationary railing, the jet on the back of her suit allowing her to drift straight back. A blast from one of the five-meter wide NERVA III engines could expel primary coolant from the nuclear reactor with over five tons of force. Aki had no intention of getting in its way. The readout from her suit’s radiation counter was increasing quickly enough to give her cause for concern. She was unsure what to do if it continued to escalate.
In the first minute, she descended 150 meters toward the Island. The graser battery passed by as she continued to drop. Landing on an area that was light gray in color, the boots of her suit touched down against the hard surface of the Island. It felt like polished marble, but Aki did not feel the density she was used to under her feet. Gravity was low; even taking a normal stride could mean reaching escape velocity. She gave a few blasts from her jet to propel her toward one of the hexagonal wells.
“The hole is approximately four meters across. The interior is a perfectly smooth cylinder with a reflective coating along its walls. This is interesting… From what I can see, it is not completely perpendicular compared to the Ring’s exoskeleton. It is somewhat tilted, perhaps aimed toward something.”
Aki peered deeper into the hole.
“There is something down there, about one hundred meters down. I am leaning over…I can see it now. Three arms are securing a disk in place.”
“Your helmet’s transmission gives a good look. It is probably the secondary mirror of a reflecting telescope,” Per said.
“I don’t think so, Per. I know scopes. The inside would be black to absorb any stray light that got trapped inside it. This is not even close. It is white and reflective.”
“It does not absorb light and gives it off instead?”
“Is it some kind of firing device for a diffuse laser?”
That explanation made more sense. This had to be the complex laser’s guidance mechanism. With the Island 130,000 kilometers across, if fired at once, the blasts would produce a bundle of amplified beams the size of Jupiter.
“What could it be for?” Aki asked. “We have already seen the graser. I cannot understand why the Builders would want this much power.”
“Maybe it’s for communication.”
“Too big, Per. It must be a propulsion system for laser sails. But where is the ship?” If it is for a ship, what could be massive enough that someone would need this much power to mine it or carry it away? The solar system did not have any precious resources or rare elements that were not readily available throughout the universe. She tried to visualize what the Builders could want. The Builders were advanced enough that they should appreciate that the solar system had life. She could not understand why they would ignore humanity or the rest of Earth’s species and build a device that could destroy it. The Ring was at a specific angle that reduced the amount of light that could reach Earth. It could not have been coincidental and was not the sort of information that such a meticulous design and construction process would have otherwise overlooked.
“Aki, what if the ships are not being built here because the ships are coming from somewhere else? Somewhere outside the solar system?” Per said.
“You’re not making sense. I was trying to think about how the—”
“What you’re sending back. That is not a propulsion system. It is for braking.”
“I have a pretty good—”
“No. The extrasolars will beam the lasers against sails to slow down, not to speed up. Based on a system capable of directing this much energy, like bomblets, it would be enough power to slow down an armada.”
Aki lifted her head and looked out into the stars. Orion, with Betelgeuse, the blue of Rigel, the Orion Nebula and Barnard’s Loop, all were in the direction the cylinder pointed.
“What would they…?” She was not sure how to finish her sentence or her thought. The Builders had to come from one of this countless mass of stars. One of those infinite pinpricks in the darkness had to be their sun. Aki understood that Per was correct. Somewhere out there, near whatever star was their home, there would be a replica of this structure she was standing on. It would launch the ships, providing acceleration to start their journey, and this would bring that fleet to a stop. With massive yet lightweight sails, ships like theirs would eliminate the need to carry their own engines or propellants. A civilization that could build such a system would have no problem constructing the Ring from such a remote distance.
“It is simple. How do you stop a photon-sail ship? We tossed that concept long ago for lack of an answer,” Per said. “Now you are standing on it.”
“I read that they’ve run tests on the idea.” The commander’s tone showed he did not want to sound as out of his depth as he was.
“The physicist and writer Robert L. Forward proposed light-sails and eventually came up with an idea for braking, reflecting the laser onto the front of the sail to slow the ship. His model had problems too. A laser beam loses strength in proportion to the square of the distance covered. It is hard to project a beam that remains strong enough for when it is time to begin deceleration. It is not applicable to long-distance trips. There are also problems presented by having the enormous sail mounted to the ship throughout the voyage.” Aki stepped back from the hole in the Island.