Exam

2026, August 23
Tau

I’m not going to know if you’re listening for a long time, but here goes. My name is William Chamer. I am, or was, a student at Caltech. Before I say anything else, I have a request. I’d like you to tell my parents “the man has a plan”. They’ll know what I mean, if you can tell them. They were living in Bangor, Maine in 2014. On a more general note, tell everyone’s relatives who still live where we are. It will have been twenty-four years, but I can’t imagine someone not having a list of the missing.

I have to trust that you’re hearing this. I’m tapping out Morse with one hand and alternating between steering the satellite dish and sweeping frequencies on a short-wave radio with the other. I’m sure this planet has a good enough ionosphere to get a signal through. I saw aurora as we came down. But I’m not sure I trust the Examiners. They said we could transmit, but I’m not sure I believe them.

You’re probably wondering what I’m talking about. I’ll start from the beginning, but I’ve only an hour or so of power in this kludge of fuel cells, so I’ll need to be quick. I’m trying to get MIT on short wave while calling you on a transmitter cobbled together from a satellite dish and a gigahertz generator. Don’t expect any miracles, or at least no more than finding that two college campuses flew twelve light years.

Two hours … no … twelve years ago I was walking along Del Mar Boulevard when the clouds disappeared. So did the other side of the street. So did the street itself, with the exception of one car, which, quite unnervingly, suddenly turned off and floated in space. By the time my eyes adjusted and I looked into the void where the pavement had been, we were past the Moon and two crescents were shrinking below us. I looked up and saw a pattern of stars not usually observed from Pasadena. Tau Ceti was straight above. Then I realized that the stars were too blue and moving, all towards the zenith. We must have been accelerating at thousands of gravities, yet I felt neither heavier nor lighter and the air pressure remained the same.

I ran for the nearest large building, the Moore electrical engineering lab. Campus was something from nightmare. I briefly saw some light on the side of the cut where Chester Street had been removed, then the Sun was invisible and directly behind us. Above, the stars had merged together. A circle of blue light was straight overhead and kept shrinking and growing brighter. By the time I made it to the logia and the door, which was unlocked, I began to worry about UV burns.

You may wonder why I don’t think I’ve suddenly started having delusions. I figure I was wondering if I was mad, which is said to be a good sign, and I doubt my subconscious would come up with a nightmare incorporating relativity. I haven’t seen any fuzzy pink elephants.

I didn’t meet anyone before I got to the lab. Inside, I started to pick my way upstairs, using my phone as a light. That was when things got weird. A man appeared on the landing. He was dressed in subdued gray, looked like a stereotypical kindly professor, and my phone lit the floor as if he was not there. He started to open his mouth. I lunged for his throat. This doesn’t do me much credit, but I guess I figured I’d hit first and ask questions later.

The figure disappeared and reappeared a few stairs up. I stumbled but managed to stay upright. As I looked up at him, he began to speak. “Mr. Chamer, I am not really here. I am projecting onto your mind. You may call me the Examiner.” The figure vanished, but the voice did not.

“You find this more comfortable. Again, this is a projection. I am reading the electro-magnetic fields your brain produces, then vibrating your middle ear bones to make you hear me. You will understand how I can do this fairly quickly. First, I must explain what we, that is me and the other Examiners, have done.”

I cursed. “You’d better have a good explanation for carrying us off, however you did it. I assume you aren’t going to dissect me.” I had started climbing the stairs again, and exited on the second floor. I knew about several labs on that level that had emergency-power fuel cells.

“Please be serious. A graduate student in physics figured out how to destroy a galaxy.” Before I could even pause in opening a door, the Examiner continued. “That statement requires elaboration. You have heard of negative matter. It is not merely the creation of a theoretical physicist manipulating super-strings in algebra. There are ways, within the technological limitations of your species, to produce neutron-star density matter where the gravitational mass is negative one times the inertial mass.

“Take a negative mass and a positive mass, put them next to each other. They accelerate indefinitely. I do not have time to explain how energy and momentum conservation hold. Just consider what can be done with such concentrated kinetic energy. Your species could produce enough to destroy a star like Tau Ceti, where we are taking you, within merely decades. Destroying the galaxy is simply a question of scale.”

“I don’t know anything! And why fly us through space?” I had found one partially charged fuel cell that wasn’t attached to a computer. I picked it up, carried it to the stairs, put it down and went back down the hall.

“We want humanity to know how to make negative mass. It is convenient for an intelligent species to have effectively limitless energy. But we cannot let you if you would do as I just described. And there is another reason. A hundred million years ago, we missed an intelligent species in our surveillance of the Large Magellanic Cloud. They committed racial suicide before we could stop them. A hundred-kilometer-diameter asteroid was induced to impact the surface of their planet, using a negative-mass-positive-mass push-pull. After that, all of the technological species in the Local Group agreed to collaborate on watching developing races. My race was assigned humanity around 6000 BCE.

“Fifteen minutes before we removed you all from Earth, the physics graduate student had an inspiration: a crude and bulky, but nonetheless effective, way to make negative matter.

“We have ways to monitor every conscious thought in a human brain by monitoring electromagnetic signals and correlating them with known stimuli. I am applying such a technique to communicate with you. In the other direction, carefully positioned negative and positive point masses are vibrating the bones in your inner ear.”

I moved a hand to the side of my head, then brought it back down as the Examiner continued. “They are eighteen hundred meters away, and there are a lot of them. They are adjusted every few microseconds, which suffices for my needs. The visual trick is harder. There we need to induce the proper signals to produce an image in your mind. That takes several minutes of monitoring your visual cortex before we can get it right, hence my delay in beginning to communicate with you through a human avatar.
“The graduate student I mentioned was not being monitored, a serious oversight. We only learned of his inspiration as he began to compose an email to another student, at MIT. By the time our moving hardware, many heavy positive and negative point masses, could be brought to bear, the MIT student had read the email and told another colleague. The Caltech student had also started to talk. We had to remove both Caltech and MIT, rather than Caltech alone.”

I still failed to see how, or more accurately now why, I and all of campus had been moved. Before I said so, however, I realized that if this thing called the Examiner were indeed reading my mind, it would be able to tell that I didn’t understand. So I didn’t say anything. Instead I picked up another fuel cell and carried it to the staircase. I had found four large cells. I had also found another student, sitting in the dark, staring at a blank wall and speaking Mandarin. I assumed that she was speaking to an Examiner, and did not interfere.

Hang on … I just had something on the short wave. It sounded like someone doing a slow chirp. I’ve switched to a monochrome in that frequency range. I hope it’s MIT.

I had been right about the Examiner. “Look around as you land. MIT should be easy to see. You think there is a planet around Tau Ceti. You are correct. There is a planet, habitable by your species, where we will land both schools. You are there for a test. That is why we have chosen the term Examiner to describe ourselves in your languages.

“I told you we want humanity to have negative mass, but only if we believe you will not misuse it. There are two ways to decide. One is to observe Earth. This is problematic for a species where change is so rapid. The other way is to test you. I cannot tell you all of the details, but there is much that you need to know.

“We have moved the main campuses of MIT and Caltech, with the majority of the student body but no professors or staff. The reasons for this are many. We needed enough people to be statistically meaningful, moving the faculty would require removing far more of Earth’s resources, and the students we have brought are relatively unattached and flexible, two traits desirable for the Test. Another obvious point is that a few students are currently the only humans who know how to make negative mass. We estimate a probability of less than one percent that anyone on Earth will replicate that inspiration within the next century. Those who know the inspiration obviously needed to be included. They will decide if and when and who to tell it to. You probably will have no use for the knowledge directly during the Test, and my telling you would defeat our purpose.

“You will be deposited on the planet with your campuses, plus some additional material. You will be observed, this time with almost as much scrutiny as we gave you and the outlying students before moving everything. We will not contact you for the duration of the exercise, nor will we intervene.

“We used a complex sequence of negative and positive point masses to prevent any pressure waves as the result of the removals. This allowed us to accelerate you at a hundred kilogravities before you left Earth’s atmosphere. You are under such acceleration now. We have blocked it by using another network of point masses. Again, I do not have time to explain just how that works with general relativity. Check out Forward’s papers in the physics journal stacks in Millikan if you need someplace to start. At the halfway point, we flipped you over and the acceleration reversed. Total subjective time to Tau Ceti will be less than two hours. Your landing site is being prepared, and you will transition to planetary gravity and atmosphere immediately at landing. We called ahead.

“There is a way to use negative matter to support a wormhole, so that information can be transferred faster than light. But no one has ever found a way to make them large enough to transport anything larger than a gamma-ray photon. Read up on Kip Thorne; once more I don’t have time…”

I have two hams at MIT! They’ve also talked to Examiners. They haven’t located a gigahertz transmitter yet, and are on the dayside of the planet anyway. Here it is now probably thirty minutes before dawn. I did see MIT as we came down. The planet has bigger polar caps than the Earth, and is a little smaller. Caltech was landed about twenty degrees before dawn, with MIT a long way east. They went under the horizon a few seconds before we touched down. They’re across ocean in that direction. I told them I’m transmitting to you. Where was I? Wormholes giving the Examiners high-bandwidth faster-than-light communication but not travel and the details of the Test.

“You must survive for decades on the planet; at least as long as it takes light to travel to the Earth and back. The level of your society and technology at the end of the Test, and your behavior during it, will determine the outcome. If you are successful, we will allow you to make negative matter, we will broaden contact, and you can keep the planet as a bonus. If you fail, we will block anyone on Earth from making negative mass, until we repeat this exam and humanity passes. In roughly twenty-four Earth years, we will speak to you again and you will know our judgment.

“The test will not be entirely cold. There are things not on campus that would be very useful to you. You must decide what they are. We can produce anything that can be made on Earth, by reading the information on Earth and sending it here. You may have twenty kilograms of supplies per person. There are a few restrictions. I am reading your mind. I will not give you anything that you intend to use against other humans or yourself, because that would defeat the purpose of the test. No nerve gases, deadly viruses, or nuclear bombs. I will also not give you any human.

“You have thirty minutes to decide before you land. Every other person on both campuses has the same decision. If you find someone else and agree as to what you want, you may pool your mass allocations. Chamer, what do you request?”

I was standing on the roof of the lab, with a pile of fuel cells, this old gigahertz generator, which I picked up on the third floor, the short-wave radio, a bunch of cables, and a multimeter. I had hauled all of these upstairs while talking, or thinking, with the Examiner. Next to me was this four-meter satellite dish. I looked at the sky. There were no visible stars. I don’t know how close to the speed of light we were, or how the Examiners blocked the radiation from cosmic rays and interstellar dust. The Sun should have been overhead, but the light was invisible, redshifted beyond human eyes.

I bent down and started connecting the cells together. I began to very carefully think out what I wanted the Examiner to give me.

The two MIT students on the short wave (a grad and an undergrad) tell me that they had the same sort of discussion with their Examiners. All the conversations and projections were different, but the hams didn’t have any information other than what my Examiner gave me. After I finished explaining what I wanted, it simply appeared, much as we must have vanished for you. I think I’ve been relatively lucky. I know one student who was on a plane when campus vanished. The Examiners mentioned ‘outlying students’. I can’t imagine flying through space encased only in a bubble of air is very pleasant, even if the acceleration is canceled. I hope she is on Earth, alive, and laughs at this.

By the time I’d explained to my Examiner what I wanted, and it (I guess that is the right pronoun) had obliged, the very brightest and bluest objects in the sky had begun to become visible again. The transmitter was almost set up, kludgey as it is. I don’t know how the gigahertz generator has reacted to having a kilowatt run through it in pulses. All the multi-meter can tell me is a rough estimate of the transmit power. But the Examiner hadn’t finished talking:

“There are a few minutes left before we leave you and I can convey some more information. Tau Ceti is an old star. It is twice as old as Earth’s Sun, but will live some billion of your years longer. You are wondering why intelligence has not arisen on the planet.

“Life started a little late and evolved relatively slowly. Microbial activity produced an atmosphere you can acclimate to about two billion years ago. An ozone layer gave the surface an ultraviolet flux comparable to Earth at the same time. Plants and animals colonized the equatorial continents. But then they had problems with further evolution.

“The planet has no large moon. The tidal forces from the star and the other planets cause long-term variations in the obliquity, with much less damping than on Earth. The oscillation periods are tens of thousands to tens of millions of Earth years. The faster cycles are analogous to Earth’s ice ages, but more severe: the axial tilt varies by ten degrees instead of one and a half.

“The land is wiped nearly clean by glaciers roughly every ten thousand years, retarding evolution. You will need to discover the details yourselves, but the next ice age is many centuries away. The debris disc in the outer system is far denser than that of Earth’s sun, so the comet impact rate is higher. There is no local intelligent life. The probability we are preventing any from evolving by putting you on the planet is about one in a hundred million.

“You will be landed in a cleared region on the coast of one of the equatorial landmasses. Your colleagues on the other campus will be deposited quite far away, but still in the tropics. The climate is comparable to the temperate regions of the Earth. You can eat many of the local species.

“Now I must leave you, Chamer. Remember that none of you will hear us or see us during the test and remember the passing conditions. You are relatively lucky in that Tau Ceti is less than 12 light years from Earth and you can talk to the rest of your species within a quarter century. We won’t stop you from communicating how to make negative mass to Earth. You must make that decision. Good luck.” The voice went silent.

The stars spread out and assumed their proper colors. One star did not move until the last few seconds before we landed. Then it started for the limb of the planet. That must have been MIT. I mentioned the ice caps and the aurora. The dayside, of which I saw about half, was ocean in the equatorial region, with what might have been a few island chains. In the northern hemisphere, the ocean was bounded by an ice-covered continent, with what I assume were mountaintops breaking through at the coast. I could not see the night side until we were very low, and only saw that we are indeed on the eastern coast of a large landmass, before we landed and what looks like a forest appeared at a distance from campus on three sides and a few scattered clouds were slipped back into place in the sky.

The trees look basically normal in the dawn twilight. Convergent evolution, I guess. I can’t tell if there is anything like grass. I can smell the ocean. It must be to the east, where there isn’t any forest. In between are a bunch of cars and blocky structures. I guess they took apartments too. There are some people gathered out there, walking a little clumsily. MIT seems to have come down in the middle of a continent. They’re surrounded by what they describe as scrubland. Their local time is about two Earth hours after noon.

The gravity is slightly lighter, about eight-tenths g. I was a bit jolted when it changed, but the big difference is the air. It isn’t thin, but must have somewhat less oxygen. My heart rate is up, but the Examiner seems to be right that we can acclimate. It’s colder than Pasadena, but that may be at least partially the time of day. MIT reports fairly warm weather, but they’re coming from New England.

The fuel cells are reading near dead and Tau Ceti is rising. There’s no time explain what I requested and why. It took me thirty minutes to explain it to something that was reading my mind. But I’ll tell you what other people ordered. I’ve seen five so far. I’m not confident about IDs. All but one were heading to the field where Del Mar once was, between campus and the coast. The north side of campus is now roughly eastward. The first had a hunting rifle with a spare scope slung over her back, and was carrying a case, probably cartridges. The second and third came together, leading a bunch of young dogs, shepards or collies. Then a man with a box full of bottles came out of Annenberg, moving a bit more unsteadily than the others. He was going in the direction of the South Houses. The last carried what seemed to be three gallon-sized paint cans and several coils of wire. I think that adds up to paint-on solar cells.

Tau Ceti is almost up now. I can barely see the Sun. I gave this frequency to the MIT hams. They’ll broadcast whenever they can, but we’ll be reserving a fair bit of power to talk to each other. Keep listening. I’ll try to give you daily updates until we can coordinate an automated transmitter. Our day is 26.5 hours, give or take a few minutes; the time-change will be rough for a while.

More people are heading over to the field. It looks like we’ll be having a pretty comprehensive discussion. I’d better go. Transmit power is down sixty percent anyway. If you don’t mind transmitting a tight beam on this frequency, no, better use the second harmonic; I’d like news of Earth. If we survive, we’ll be listening.

2026, August 23
Tau, MIT

In the basement of pika – the house of the ex-fraternity had been picked up intact – Elmund Gera was sweating as he finished joining the power lines into a form such that the refrigerator and other essentials could be turned back on. He silently blessed the activist in the class of 2012 who had installed all those solar panels as part of Work Week. Less silently, Gera was also arguing with the other members of the co-op. They couldn’t be quite as free living and anarchic in the new environment, and recognized that. But they did not yet appreciate his business plan.

Zijun Xin had been dropped in his car about three miles from the bulk of campus. Well ahead he could see Harvard Bridge, now simply a double line of pillars with a road across the top. But he had been going on foot, to not disturb the wildlife. Already he had figured out three kinds of plants and one four-segmented invertebrate and pieces of what passed for the bark of one tree that might be edible, but he hadn’t tested them for himself.

Julian walked slowly down the Infinite Corridor, softly singing and trying to savor the cold latte he’d managed to snag before the cup hit the floor back at the coffee shop. It was a strange song: grief and sympathy and hope and defiance, conveyed in what sounded like a mixture of Latin and Sanskrit. He stopped at every room he came to, looking for anyone who had not started to move about. Julian focused on finding people and the taste of the now-precious coffee. He did not yet let himself grieve for Henry, who was now twelve years gone.

Kathryn crouched on the roof of the MIT chapel. Across the green, a scattered mob of about thirty had five people at bay against the side of the auditorium. Right now, the mob was stopped by the scattering of laser spots across the ground in front of them. But those were only her decoys. Kathryn was the only one in the area who’d been given weapons. If the mob didn’t move back there would be violence. There was no time to get backup, and this was only the second hour since they had landed.

Tau, Caltech, Betchel Mall & Rose Gardens

Mina Grohar stumbled as the perfectly transparent floor of force she had been standing on for the past two hours was replaced the familiar terracotta walkway and beds of roses just north – no, now east, if that was dawn – of the Geological and Planetary Sciences buildings. Stumbling for her first few steps, she was glad of the boots she’d taken out of her luggage while she stifled the vertigo of flying in a bubble of air held in place by an invisible screen of point masses. The Examiners had ripped her off a plane eight kilometers above the Pacific.

Shrugging off the disorientation of the lower gravity, she grabbed the handles of her two suitcases, now twenty kilograms heavier than when she’d last hefted them in New Zealand, and started towards the door. She planned to drop the luggage off inside and then try to find Will. Then she heard the screams from the base of Millikan Library’s nine-story façade. She dropped the handles and did her best to run in that direction.

2026, April 24
Earth, University of Chicago

The thesis defense is usually a formality. If you haven’t produced good work, written good papers, and been able to synthesize them into at least a semicoherent whole, your advisors won’t let you get that far. So when, at the end of an hour of discussion of planetary formation around brown dwarfs and application of JWST to the observations, Vesna was dismissed with a handshake and a “Congratulations, Doctor Grohar!”, she was merely happy and relieved, not surprised.

The surprise came later, after the champagne, a call to her mother in Trieste, and lunch. She’d gone to an authentic sushi place (quite the splurge) with Janez, who had come over from Wash U. for the weekend, her officemates, her committee, and a couple of other students from the department. Then Janez had gone off to see “The List” – the items that the Chicago undergraduates would be asked to retrieve for their annual scavenger hunt in a couple of weeks. He’d gone with Kal Sarswati. Vesna sensed some interest on her part, but wasn’t sure he picked up on it. Kal was a nice enough girl, so she wasn’t about to become parental, even though their mother had asked her to keep her younger brother out of trouble.

She was alone in her office, cleaning up papers. Even after thirty-five years of every grad student having a computer on their desk with successively larger amounts of memory and higher resolution displays, she had a couple drawers full of old problem sets, answer keys, and hard copy books. Her computer chimed, signaling a video call that had passed the spam filters. She moved into the range of the camera. “Yes?”

It was Mathias Lissajous, who’d offered Vesna a post-doc with ESA in Paris, with an option on a more permanent position. She wasn’t sure if she wanted to accept, but it was one of the better offers she had had – actually the only one that was more than a placeholder. He had mentioned being in Chicago for the last conference in the Gaia series, and wanting to arrange a meeting.

“Dr. Grohar?” French-accented English and a face framed by the scenery moving by the windows of the El.

“As of a couple hours ago. What can I do for you?”

“A short meeting, if you don’t mind. I’m just on my way over to campus. If there is someplace private we could talk…”

When Lissajous arrived, there was the normal exchange of pleasantries and a polite inquiry about the defense as he took out his tablet and she closed the door. Vesna did not observe the wireless Internet in the room quietly ceasing to function as the Frenchman thumbed a corner of his display, nor the brief light pulse as the machine scanned his retina.

“I’m afraid even our final re-analysis of the Gaia data only pins down the positions of your objects to maybe 10%.” Vesna had been dealing with brown dwarfs so faint that they were at the limit of the spacecraft’s survey, and the measurements weren’t very good. “But there is an animation our techie put together. Please.”

He handed her a pair of display glasses. They were like wraparound shades but wired with forty million miniature fiber optics and batteries and antenna in the earpieces. He pulled a second pair from another of his pockets.

Vesna had seen these before; the latest fashion in portable media was heads-up video; but she hadn’t used them. She was looking towards the tablet as she put them on, only to see a three-dimensional star map floating above the display, labels showing that it was all stars within ten parsecs of the Sun. “Very pretty.” She meant that, but was wondering when the science or the job discussion would show up.

“I know, it’s mostly PR, but this map contains all the Gaia data. Look at this …” Lissajous zoomed in on Tau Ceti, the other stars flying away, seeming to be behind the walls, until the image showed an uncertainty region eight light-hours across, with a vector showing the star’s motion through space. “You know about Tau Ceti d, right?”

“Of course.” Everyone knew about the success of the big optical interferometers. It had been all over the media as well as the journals. Tau Ceti d was the prize. It was the closest Earth-like planet other than the one she was standing on. If the data were good enough to get a spectrum better than just showing the ozone band … but that wasn’t Vesna’s project, and she didn’t have any bright ideas on it anyway.

“How’d you like to go there?” Even with a deadpan delivery, the combination of his accent and that question made Vesna giggle. The Frenchman smiled slightly, then said, “I am quite serious.” and waved a hand over the tablet.

This time Vesna saw the logo of the Eufor and the flash of the retinal scan. “Captain Lissajous of Eufor Research, as well as Dr. Lissajous of ESA, I’m afraid.” He reached into an inner pocket and handed her a holograph ID. After she was satisfied, she handed it back. “Care to explain all this?”

The Frenchman indicated the schematic of a spacecraft that now floated in the projection. “Do you recognize Astral Mining’s ship?”

“I’ve seen it before. They launched it through private contractors in Guiana, using ESA hardware. But what does that have to do with Eufor, Tau Ceti, or me?”

Astral Mining was a strange company. It had emerged out of obscurity in 2019, with a bankroll of sixteen billion euros. It had one simple goal: to mine space for profit. It wasn’t clear who was backing the group. Rumors circulated of eccentric billionaires, of oil companies that hadn’t bought the rights to shales desperate as even deep reservoirs went dry, of governments in shadowy negotiations. Only a few things were certain: one, Astral delivered the goods – platinum and gold from the near-Earth asteroid 1950 DA falling from the sky into the Mojave and Lake Eyre Basin; two, they had attracted a staff of the best and brightest from around the world; three, they would not let anyone else into their game.

There wasn’t anything violent or underhanded. Astral just sold futures on precious metals so cheaply that no one else could replicate their spacecraft and mine another object. They had even taken over delivery of deep space probes, picking them up in low orbit from the contractor rockets and flying away on ion engine tugs. There were rumors that Astral had built scaled-up boron fusion reactors, that Astral would hold the global economy hostage once they drove the South Africans bankrupt, that Astral was building huge solar arrays to beam power to the ground and end all arguments about how to mitigate the energy and carbon crises. But with their monopoly on space industry, who was to say? Even repointed spysats couldn’t get good images of their mining rig.

Lissajous asked Vesna, as he moved his fingers across the tablet, “Ever wonder where they got their money and their staff? Here’s their group of investors.”

The budget rolled out, a single page of text suspended in the projection. Four billion euros from Eurofor, grouped into sections spanning 2016 to 2019, recording appropriations from half the military organizations in the EU. A similar amount from the US, there mostly from the Air Force and Navy. Russia had contributed two and a half billion, China three. There were smaller amounts from Australia, Japan, Canada, and other states, which made up the difference.

“Dr. Grohar, my tablet has saturated the room against electronic interference and audio bugging, and you have not seen this document. That said, I am allowed to show you it, and also this…”

The projection of Astral’s DA-1 came back; followed by it deployed at 1950 DA, a lumpy chunk of nickel-iron with 50 parts per million of platinum-group metals. The model of DA-1 as it was now showed a return aeroshell attached to a ion-engine tug waiting to be filled, the mirrors of original solar thermal power plant, the zero-gee smelter, and a half-constructed centrifuge to provide artificial gravity for the present crew and later arrivals. Overshadowing all of these was half of a square kilometer of solar array.

Lissajous indicated the array. “That will produce a gigawatt of power when it is done. Equip it with maser transmitters and it could power a city, or swat ICBMs and spysats. That’s why no one else in the militaries, outside of those in the Group, know about Astral and DA-1. The temptation to misuse it would be too great.”

Vesna was still confused. “Members of eight rival militaries are cooperating with each other to build power satellites and you can’t tell your superiors? I get the cooperation. You’d fail-safe the powersats so that anyone could cut them off. I see my part in this: give a good public face to Astral by funding basic research. But Tau Ceti d?”

“We don’t want to build a power satellite … or a weapon. When the gigawatt is ready, we will do this.” Another handwave. The square of solar panels, complete, detached from DA and flew through space with a large payload and a grid of ion engine flames trailing behind. It joined another asteroid, this one a combination of carbonaceous and nickel-iron material. “We made this object by a targeted collision a year and a half ago. We call it the Pusher. The gigawatt is going to do two things: power the engines on the tugs to move the Pusher into a nearly circular orbit at two-tenths of an AU from the Sun, and fuel the construction of more array. We need a few petawatts for what we want to do. Meanwhile, DA will be building this.” The last image in the sequence: a massive sail of monolayer membrane, dwarfing the projection of DA, with a pinpoint at the center of a network of shrouds. “We call it the Gamble. It is going to Tau Ceti, and I’m one of the recruiters for the crew.”

The astrophysicist did not doubt Lissajous, but his little tech display wasn’t the selling point. It was the apparently valid ID, what she knew of the Frenchman’s career as an astronomer and the information she did have on Astral that convinced her. “So, if I accept your job offer, eventually I’ll be given a job with Astral, sent up to DA, and stuck on board? When are you planning on launching this thing? Why are the military types involved in something like this? And why me?”

“Actually, our plan is a little different. Astral and the Space Group aren’t satisfied just with gambling in the stars.” – or had he said gamboling? – “We want to spread a small but permanent and unified human presence throughout the Solar System first. So you’ll be offered a job at Astral to establish an observatory at a Mars colony when they open it in 2030. DA is starting to cast the spacecraft for that. You’ll come back from Mars by 2033, and Gamble launches once the Pusher array is ready and tested, in mid-2034. So far, we’ve managed to keep to schedule. After launch, Gamble will be accelerated towards the BL Ceti-UV Ceti red dwarf binary, which is just off the course to Tau Ceti, to drop off an automated observation station and swing past the stars onto the final course.

“As to why: a partial answer to why you is that you are young, in good enough health, apparently willing to sacrifice a lot for this cause, qualified on a professional basis, and willing to accept a shadow military commission and the discipline and orders that follow from it.

“The rest of why you, and why generals serving eight different flags have agreed to work together covertly, interpreting their oaths of service creatively, is the same: the Vanishing. Your sister.”

Vesna hesitated, momentarily caught by memory of the day in 2014 when her parents had told her Mina was gone, vanished between Christchurch and Los Angeles as the steward handed her a dinner tray, with only two naturally shed hairs left behind. Her and all the rest of the students of the Caltech Geophysics ship course.

After a moment, the Frenchman continued. “Most of the world militaries have become quite sensibly paranoid about the Vanishing. If something that can do that is operating, they want to know who, what, and how to stop it. When there isn’t a clear way to redress the wrong and all you can do is clean up the mess and try to heal, preemptive justice, just below a threshold of acceptability, comes to have great appeal. The interventionist politics of the US in 2015 to 2020 were a symptom of this. The generals of the Group had a different reaction.

“Something caused the Vanishing. We don’t know what. It may have been natural, it may have been a weapon that someone is hiding, it may have been an accident, but something that breaks the normal rules was there. So some people need to not be here if it happens again. Thus the motivations for expansion – get off Earth, but keep everyone who isn’t trustworthy on the planet. The founding members of the Group knew each other and trust each other implicitly and so far no one has betrayed us. We police ourselves, mix crews so that members of all nations can work together and watch each other, and we need each other’s resources to succeed.

“Most importantly, Gamble needs a crew. So, for ESA I offer you a job. I also do so for Eufor and for Astral and for the Space Group. You lost your sister to the Vanishing. This isn’t vengeance, or running away, but it is a way to act in her memory and maybe to protect against it happening again. Will you accept?”

Vesna thought for a moment, balancing: Earth as it was, versus the promise of the stars; Matka, Janez and her friends, versus the discipline of this Group and her memory of Mina; a grant-bound career in academia versus research through a corporation that would give her a telescope on Olympus Montes. Okay, so that last wasn’t really a choice. “When do I start?”

“Can you be in Paris in two weeks?” He tabbed the computer again and the projection vanished. He took off his goggles. “You deserve a little vacation. By the way: so far as anyone else knows, unless you get permission for release, this is just a research position that will eventually feed into a job with Astral. That is the truth, up to a point.”

“I understand.” Vesna handed back her pair. “By the way, what would have happened had I refused?” She still had a lingering doubt.
“Then the Group would have abandoned me, that tablet would erase itself, and my friends at Astral would have never heard of me.” He saw her acceptance of this, recognized it as the last dispelling of distrust. Opening the door, he said. “Thanks again, and see you Paris. Au revoir.”

2038, July 18
Earth, Atacama Desert

The signal-processing computer dispassionately said “Modulated signal from Tau Ceti has ceased. Continued monitoring ordered to the follow-up arrays. The Allen Array and Tidbinbilla are currently tracking.”

Kal placed another call to the microwave array on the analog phone.

“You said you heard what I heard? … The VBLI got it too. Can we hold off until tomorrow afternoon on the release? … We have to inform Berkeley and the Chinese. We’ve been using their arrays. Probably ESA too. I just want to hold off on the public. … I’ll say we have a potential signal and we want confirmation. … It’s true enough. We should hear again by tomorrow. … Don’t ask me. I went to Chicago and Cornell and I started ten years after they disappeared. But back in 2014 they were friendly rivals. … I’m not worried about them. It’s these ‘Examiners’. … They’re not nice cuddly bug-eyed monsters.”

After she hung up, the AI told her a flood of emails and networked calls had come in. The computer was interfacing with the rest of the system now that the hardware switches had been thrown. “Give them an auto-response. I need to think. No, wait. Call Janez.” About nine thousand had vanished in 2014, including her husband’s older sister, and if the message could be believed, they all were, or had been, on the second planet of Tau Ceti in 2026. Twelve years ago, and another twelve before they could know that Earth had heard them. Maybe the Gamble, and Vesna, would help.

Janez was off-line, walking their daughter to the crèche at Oxford before heading over to his job at the green architecture firm, but Kal left a message, describing what she had heard and asking about the Examiners. What would they do? What had they done? The cosmologists were currently invoking something like negative matter to explain the accelerating expansion of the universe. Now they knew the stuff was real and that a lot of it could be made and used as a weapon and as a way to travel at so near the speed of light that it made no difference. What would happen? The Examiners claimed that no human was likely to replicate the inspiration, but had they assumed that every physicist on Earth might attack the problem? And could they, no, would they intervene if there were a catastrophe? Would there be any way to tell if there had been an intervention? Only time, and perhaps a collection of twelve-lightyear distant college students, could tell. That was one reason Sarswati had stalled. The message spoke of daily updates.

Twelve hours later. MIT should have been able to find the Sun in their night sky and transmit, but there was nothing that the receivers at Robledo de Chavela could hear. What had happened? The message had claimed that MIT was there and that there were two ham operators able to bounce signals halfway round the planet. Where were they?

The next day. Kal was still alone in the control building. She had slept, although badly, in the operator’s quarters and the Chilean police had kept out a few enterprising newsagents who had decided that driving two hundred miles into the desert was preferable to a videoconference. There should be a new message anytime. Because of the two-and-a-half hour difference in length-of-day, this message should begin with the star well overhead. A large subarray tracked Tau Ceti.

As an hour passed, she became more and more worried. The videoconference was scheduled that afternoon, and that could not be stalled. Then the AI reported that a signal was coming down, steadier and stronger than the day before. Kal sat, to hear the words of the distant world.

2026 August 24
Test Year 0, Day 1
Tau, Caltech

This is Chamer again. I’ll assume that you heard my message yesterday. If not, I’ve made a summary and it will play afterward. A CS undergrad was able to rig up a recorder program, which will take the Morse and replay it at ten times the speed. We’ve been lucky in what people requested. Between solar cells, batteries and human-powered generators, we have about forty kilowatts, plus the solar arrays on top of the parking ramps that will give a megawatt during the day once they are reconnected. Power is rationed, but I’ve got two kilowatts for this morning’s transmission and a hundred watts to talk to MIT. The gigahertz generator they were using had seen a lot of use, and gave up the ghost as they powered it on. You should hear from them relatively soon. In any case, they have asked me to rely a message.

Power rationing is rather strange. Those with power supplies barter with those with weapons for food. A sniper shot three one-hundred-kilo lizard-like creatures, each with six legs and no tail. A hundred people volunteered to test them for edibility. Others, including most of the vegetarians, are experimenting with fruits and nuts. So far, we’ve had a few things people can’t keep down but nothing terrible. The worst illness here was from someone trying to cook frogs from the Baxter pool, although that might also be alcohol poisoning.

The collies I mentioned yesterday are amazingly well domesticated, although they do try to herd the squirrels. Their owners tell me that the dogs are the result of the Sheep Dog Society’s breeding projects and the smartest dogs they could think of. That may be good or bad: I saw one of the pups tracking the scent of one of the quasi-lizards and try to follow it into a propane grill. Personally, the German Shepards and the huskies are more useful.

It warmed up to twenty-two C in the afternoon. The astronomers say that we’re five degrees south of the equator, so the temperature shouldn’t change too much seasonally. It was sunny and dry, although the surrounding area implies a fair bit of rainfall. MIT is about three degrees north of the line, and almost exactly a hundred and twenty degrees over. We’ve agreed to use the mid-longitude as the meridian.

I’m using a slightly less kludgey version of the transmitter I made yesterday. Moore Lab is about two hundred and fifty meters from the coast. The furthest apartments are about a hundred meters from the shoreline, which is a twenty-meter high cliff. A rock climber reports hard granitic rock for most of the distance, but we have about four meters of soil at the edges of campus. We seem to have requested some of practically every seed committed to the Longyearbyen vault, although only a small amount of ground has been broken so far.

The forest on three sides of us is really three small woods, about ten kilometers square total. The rest of the area is covered by some loose groundcover. The plants are using something close to type-A chlorophyll, although they have a bluish cast. A fair-sized stream runs into the sea to the south, through a rather pretty set of falls. The mechanical engineers are talking about damming it and setting up hydroelectric.

A few geologists went on a joyride in two of the departmental field-trip vans. This terrain extends for about twenty kilometers inland and far further north and south. Further from the coast, the land becomes hillier. They found a crude vein of iron. Some seismologists are talking to the chemists about getting a lot of explosives made up. They want to look for oil.

I regret to report that we’ve had four successful and two attempted suicides. Details are in the compressed message, but three people jumped off Millikan while we were flying and two took pills. One a mixture of cyanide and HF: he died despite a massive shot of hydroxycobalamin from a labmate. The other found sodium thiopental barbiturate: she’s alive but basically in an induced coma. The last attempted seppuku unsuccessfully. We’re not sure if he will survive, but his intestines are intact; he only cut skin and adipose tissue. Thank God we have a few requested surgical kits and people who know to use them.

Those of the suicides who wrote notes seem to have been advocating voluntary extinction. The consensus of everyone else is that suicide is something the Examiners do not approve of and that we want to go on living.

There have been a number of fights. About a third of the physics students were assaulted yesterday, either in transit or shortly afterwards, fortunately only by individuals so there are no major injuries. One of the physics undergrads was attacked by a man with a knife, but he had forgotten that she won the 2013 California shodokan aikido randori contest. He remembered very quickly, and is suitably repentant. The fights seem to have been spontaneous and not premeditated, but the physicists are still a little on edge.

At MIT, with the larger population, there were some group attacks. Several of their physicists were briefly held up at W16 by a small mob, but that dispersed quickly when laser spots appeared on five chests and a voice from a loudspeaker began to explain certain facts, such as ‘…killing each other is probably not what the Examiners intended, but if you all feel like dying…’. After everyone had calmed down, three students holding five laser pointers between them walked out of the building. They’d been hiding behind the mirrored glass. We’d only been here an hour, and already MIT has had a hack. Fortunately, it served its purpose: anger and resentment has, at least temporarily, been converted into laughter and enthusiasm.

Despite all of this, the four funerals here (the bodies were cremated using gasoline), and the two who are under sedation, things have been remarkably orderly.

The group discussion I mentioned at the end of yesterday’s message lasted for only three hours despite fifteen hundred people attending, probably because everyone was hungry and/or needed to run into the woods for a moment. A crew has taken it upon themselves to dig latrines around the edges of campus and to clean up the bathrooms after finding out what the toilets would do. There is water in the holding tanks, but the ends of the pipes need to be dug out and re-routed.

We have a mix of technology. The quasi-lizards I mentioned were obtained using a heavily modified form of a Mini-Hecate 0.338 high-velocity rifle, then roasted using the gas grills. A fire of local vegetation was started, but made some noxious fumes. Once the guns run out of shells, the compound and crossbows will see a lot of use. Our main power supply will be the solar panels. The EEs are claiming 200 kilowatts online by tomorrow, plus these wonderful betavoltaic tritium batteries and two bicycle generators.

Yesterday, I didn’t have time to say what the Examiners gave me. I still can’t describe everything, because I only have transmit power for the next ten minutes and there are more important matters, but I will tell you about one item. I have a copy of the Honjo Masamune. I hope the Tokugawas have found the original. I requested the copy because the philosophy of Masamune has important applications to this test.

Morale is surprisingly high here, and seems good at MIT. When I called them just before this transmission, they told me they had found an edible plant that looks very much like the Sponge, as well as describing the hack and its context. All of the above activity may be temporary, with people only co-operating until there is a reliable food source. I noticed that those who had requested rations are somewhat less eager to work. But there is something far more important.

I told you MIT has a message. So does Caltech. After the meeting yesterday, I was approached by two of the physics grad students. They had not spoken much during the meeting, in which everyone asked and was asked who had had the inspiration. Some of the asking was a little threatening, but no one has faulted me for yesterday’s transmission.

These two told me their names and the name of one student at MIT. They asked that I call MIT and ask if anyone there wanted to talk to anyone here. When I called, the operator (the undergrad from yesterday) asked whom I wanted. I gave the name. Another voice gave the names of the grad students with me and asked ‘Which undergrad knows?’ I handed a microphone to one of the grad students on my end. He gave a name I recognized, a physics undergrad at MIT. Then the two started to talk. It soon became clear who these four are. They know how to make negative mass.

They argued for thirty minutes. They weren’t discussing physics. The first argument was if the MIT ham and I could be trusted. When they decided that we could, they began to argue about if they should divulge their information. Eventually, they reached an agreement. Starting tomorrow, and continuing whenever we can spare the time and power, they will give seminars on the relevant physics, until everyone here knows how to make negative mass, on the same level that everyone knows how to make a fission bomb. This should defuse at least some of the resentment.

The physicists had one other argument. The Examiners told us they wouldn’t stop us from broadcasting the knowledge of negative matter to you, but they may have lied. We can’t know, for twenty-four years, if you are even receiving our messages at all. We can’t control who reads the messages, because our beam is far larger than the Earth’s orbit. And we can’t afford to transmit the knowledge if it will be misused. Negative matter can’t be made here, but if the information reaches Earth the resources of a small nation or a large corporation could destroy the entire planet. The four physicists do not want to be responsible for the death of every human on Earth.

Everyone here will know how to make negative mass, but will not be able to do so until we have made many other things. We can agree on who broadcasts what and who does not, because there are so few of us. And thus the four physicists, whose names I cannot say lest those inspire you, made their second decision.

The Examiners are testing nine thousand humans to see if we are responsible. They claim to communicate faster than light and to have left it to our judgment to tell the rest of humanity the inspiration. If we send a signal that they don’t like they can signal ahead and block it. But if they speak the truth, we have only one reasonable option.

We are being tested as a proxy for the entire human species. For that we apologize. But before we tell you how to make negative matter, we must test you in turn. You’ll need to call us. Everyone on Earth can receive this message, and everyone can talk back. Starting in a little under twenty-four Earth years, we will hear what the human race has become. Then we will decide if we should tell you. It may take us years to make the decision, but within a few decades you will either know this near-infinite power, or you will know that we refuse to tell you unless the Examiners tell us that humanity passes their test.

We will keep calling you, telling what happens to us and what we learn of this world. If nothing else, you will know how we attempt to pass the Examiners’ test. Let this be your equivalent of the twenty kilograms we were given. Caltech listening out.

Will stopped his focused tapping at the transmit key, flipped a switch and pressed the enter key on a laptop. Now the computer would take over the jobs of tracking and transmission and he could go meet Mina and try to provide consolation.

2038 July 19
Earth, Atacama Desert

The AI detected a ten-fold increase in the speed of the signal. It decoded this new message and found that it was largely a copy of yesterday’s and contained little new information except six medical reports, written in a strangely professional manner. Sarswati remained seated in her armchair for some time, then began to prepare her release statement. The prewritten form wasn’t going to do the job.

An hour before the videoconference was slated to begin, the half-dozen staff of the microwave observatory arrived in the control room. As the first confirmers of the signal, they would be in the release.

Sarswati went to a refrigerator in the corner of the room. She took out a dusty bottle and wiped it off. It was 2018 Heidsieck Monopole Champagne. A cabinet produced glasses.

She handed out the glasses and popped the cork of the bottle. “A toast. Humanity is taking the qualifying exam.”