‌“All right,” I said, looking at the clock. “We have one minute until the bell. You know what that means!”‌

“Lightning round!” yelled my students.

Life had changed surprisingly little since the announcement about the Petrova line.

The situation was dire and deadly, but it was also the norm. Londoners during the Blitz in World War II went about their day as normal, with the understanding that occasionally buildings get blown up. However desperate things were, someone still had to deliver milk. And if Mrs. McCreedy’s house got bombed in the night, well, you crossed it off the delivery list.

So it was that with the apocalypse looming—possibly caused by an alien life-form—I stood in front of a bunch of kids and taught them basic science. Because what’s the point of even having a world if you’re not going to pass it on to the next generation?

The kids sat in neat rows of desks, facing the front. Pretty standard stuff. But the rest of the room was like a mad scientist’s lab. I’d spent years perfecting the look. I had a Jacob’s ladder in one corner (I kept it unplugged so the kids didn’t kill themselves). Along another wall was a bookshelf full of specimen jars of animal parts in formaldehyde. One of the jars was just spaghetti and a boiled egg. The kids speculated on that one a lot.

And gracing the center of the ceiling was my pride and joy—a huge mobile that was a model of the solar system. Jupiter was the size of a basketball, while wee Mercury was as small as a marble.

It had taken me years to cultivate a rep as the “cool” teacher. Kids are smarter than most people think. And they can tell when a teacher actually

cares about them as opposed to when they’re just going through the motions. Anyway, it was time for the lightning round!

I grabbed a fistful of beanbags off my desk. “What is the actual name of the North Star?”

“Polaris!” said Jeff.

“Correct!” I threw a beanbag to him. Before he even caught it, I fired off the next question. “What are the three basic kinds of rocks?”

“Igneous, sedentary, and metamorphic!” yelled Larry. He was excitable, to say the least.

“So close!” I said.

“Igneous, sedimentary, and metamorphic,” said Abby with a sneer. Pain in the ass, that one. But smart as a whip.

“Yes!” I threw her a beanbag. “What wave do you feel first during an earthquake?”

“The P-wave,” Abby said.

“You again?” I threw her a beanbag. “What’s the speed of light?” “Three times ten to—” Abby began.

“C!” yelled Regina from the back. She rarely spoke up. Good to see her coming out of her shell.

“Sneaky, but correct!” I chucked her a beanbag. “I was answering first!” Abby complained.

“But she finished her answer first,” I said. “What’s the nearest star to Earth?”

“Alpha Centauri!” Abby said quickly. “Wrong!” I said.

“No, I’m not!”

“Yes, you are. Anyone else?” “Oh!” Larry said. “It’s the sun!”

“Right!” I said. “Larry gets the beanbag! Careful with your assumptions, Abby.”

She folded her arms in a huff.

“Who can tell me the radius of Earth?”

Trang raised his hand. “Three thousand, nine hundre—” “Trang!” Abby said. “The answer is Trang.”

Trang froze in confusion. “What?” I asked.

Abby preened. “You asked who could tell you the radius of Earth. Trang can tell you. I answered correctly.”

Outsmarted by a thirteen-year-old. Wasn’t the first time. I dropped a beanbag on her desk just as the bell rang.

The kids leapt from their chairs and collected their books and backpacks.

Abby, flush with victory, took a little more time than the others.

“Remember to cash in your beanbags at the end of the week for toys and other prizes!” I said to their retreating backs.

Soon, the classroom was empty, and only the echoing sounds of children in the hallway suggested any evidence of life. I collected their homework assignments from my desk and slipped them into my valise. Sixth period was over.

Time to hit the teachers’ lounge for a cup of coffee. Maybe I’d correct some papers before I headed home. Anything to avoid the parking lot. A fleet of helicopter moms would be descending on the school to pick up their children. And if one of them saw me, they always had some complaint or suggestion. I can’t fault someone for loving their kids, and God knows we could do with more parents being engaged in their kids’ educations, but there’s a limit.

“Ryland Grace?” said a woman’s voice.

I looked up with a start. I hadn’t heard her come in.

She looked to be in her mid-forties, wearing a well-tailored business suit.

She carried a briefcase.

“Uh, yeah,” I said. “Can I help you with something?”

“I think you can,” she said. She had a slight accent. Something European

—I couldn’t quite put my finger on it. “My name is Eva Stratt. I’m with the Petrova Taskforce.”

“The what?”

“The Petrova Taskforce. It’s an international body set up to deal with the Petrova-line situation. I’ve been tasked with finding a solution. They’ve given me a certain amount of authority to get things done.”

“They? Who’s they?”

“Every member nation of the UN.” “Wait, what? How did—”

“Unanimous secret vote. It’s complicated. I’d like to talk to you about a scientific paper you wrote.”

“Secret vote? Never mind.” I shook my head. “My paper-writing days are over. Academia didn’t work well for me.”

“You’re a teacher. You’re still in academia.”

“Well, yeah,” I said. “But I mean, you know, academia. With scientists and peer review and—”

“And assholes who get you kicked out of your university?” She raised an eyebrow. “And who got all your funding cut off and ensured you never got published again?”

“Yeah. That.”

She pulled a binder out of her briefcase.

She opened it and read the first page. “ ‘An Analysis of Water-Based Assumptions and Recalibration of Expectations for Evolutionary Models.’ ” She looked up at me. “You wrote this paper, yes?”

“I’m sorry, how did you get—”

“A dull title, but very exciting content, I have to say.”

I set my valise on my desk. “Look, I was in a bad place when I wrote that, okay? I’d had enough of the research world and that was sort of a ‘kiss-my- butt’ goodbye. I’m much happier now as a teacher.”

She flipped a few pages. “You spent years combating the assumption that life requires liquid water. You have an entire section here called ‘The Goldilocks Zone Is for Idiots.’ You call out dozens of eminent scientists by name and berate them for believing a temperature range is a requirement.”

“Yeah, but—”

“Your doctorate is in molecular biology, correct? Don’t most scientists agree that liquid water is necessary for life to evolve?”

“They’re wrong!” I crossed my arms. “There’s nothing magical about hydrogen and oxygen! They’re required for Earth life, sure. But another planet could have completely different conditions. All life needs is a chemical reaction that results in copies of the original catalyst. And you don’t need water for that!”

I closed my eyes, took a deep breath, and let it out. “Anyway, I got mad, and I wrote that paper. Then I got a teaching credential, a new career, and started actually enjoying my life. So I’m glad no one believed me. I’m better off.”

“I believe you,” she said.

“Thanks,” I said. “But I have papers to grade. Can you tell me why you’re here?”

She put the binder back in her briefcase. “You are aware of the ArcLight probe and the Petrova line, I assume.”

“I’d be a pretty lame science teacher if I wasn’t.” “Do you think those dots are alive?” she asked.

“I don’t know—they could just be dust bouncing around in magnetic fields. I guess we’ll find out when ArcLight gets back to Earth. That’s coming up, right? Just a few weeks from now?”

“It returns on the twenty-third,” she said. “Roscosmos will recover it from low-Earth orbit with a dedicated Soyuz mission.”

I nodded. “Then we’ll know soon enough. The most brilliant minds in the world will look at them and find out what they’re about. Who’s going to do that? Do you know?”

“You,” she said. “You’re going to do it.” I stared blankly.

She waved her hand in front of my face. “Hello?” “You want me to look at the dots?” I said.

“Yes.”

“The whole world put you in charge of solving this problem, and you came directly to a junior high school science teacher?”

“Yes.”

I turned and walked out the door. “You’re lying, insane, or a combination of the two. I have to get going now.”

“This is not optional,” she said to my back. “Seems optional to me!” I waved goodbye. Yeah. It wasn’t optional.

When I got back to my apartment, before I even got to my front door, four well-dressed men surrounded me. They showed me their FBI badges and hustled me into one of three black SUVs parked in the complex parking lot. After a twenty-minute drive where they refused to answer any of my questions or even speak to me at all, they parked and showed me into a generic-looking business-park building.

My feet barely touched the ground as they led me down an empty hallway with unmarked doors every 30 feet or so. Finally, they opened a set of double doors at the end of the hall and gently nudged me inside.

Unlike the rest of the abandoned building, this room was full of furniture and shiny, high-tech devices. It was the most well-stocked biology lab I’d ever seen. And right in the middle of it all was Eva Stratt.

“Hello, Dr. Grace,” she said. “This is your new lab.”

The FBI agents closed the doors behind me, leaving Stratt and me alone in the lab. I rubbed my shoulder where they had manhandled me a little too hard.

I looked at the door behind me. “So…when you say ‘a certain amount of authority’…”

“I have all of the authority.”

“You have an accent. Are you even from America?”

“I’m Dutch. I was an administrator at ESA. But that doesn’t matter. Now I’m in charge of this. There is no time for slow, international committees. The sun is dying. We need a solution. It’s my job to find it.”

She pulled up a lab stool and sat down. “These ‘dots’ are probably a life- form. The exponential progression of solar dimming is consistent with the exponential population growth of a typical life-form.”

“You think they’re…eating the sun?”

“They’re eating its energy output at least,” she said.

“Okay, that’s—well, terrifying. But regardless: What the heck do you want from me?”

“The ArcLight probe is bringing the samples back to Earth. Some of them might still be alive. I want you to examine them and find out what you can.”

“Yeah, you mentioned that earlier,” I said. “But I have to believe there are more qualified people to do this than just me.”

“Scientists all over the world will be looking at them, but I want you to be the first.”

“Why?”

“It lives on or near the surface of the sun. Does that sound like a water- based life-form to you?”

She was right. Water simply can’t exist at those temperatures. After about 3,000 degrees Celsius, the hydrogen and oxygen atoms can’t stay bound to each other anymore. The surface of the sun was 5,500 degrees Celsius.

She continued. “The field of speculative extraterrestrial biology is small— only five hundred or so people in the world. And everyone I talk to—from Oxford professors to Tokyo University researchers—seems to agree that you could have led it if you hadn’t suddenly left.”

“Gosh,” I said. “I didn’t leave on good terms. I’m surprised they said such nice stuff about me.”

“Everyone understands the gravity of the situation. There’s no time for old grudges. But for what it’s worth, you’ll be able to show everyone you were right. You don’t need water for life. Surely that must be something you want.”

“Sure,” I said. “I mean…yeah. But not like this.”

She hopped off her stool and headed to the door. “It is what it is. Be here on the twenty-third at seven I’ll have the sample for you.”

“Wha—” I said. “It’ll be in Russia, won’t it?”

“I told Roscosmos to land their Soyuz in Saskatchewan. The Royal Canadian Air Force will recover the sample and bring it directly here to San Francisco via fighter jet. The U.S. will allow the Canadians use of the airspace.”

“Saskatchewan?”

“Soyuz capsules are launched from Baikonur Cosmodrome, which is at a high latitude. The safest landing locations are at that same latitude. Saskatchewan is the closest large, flat area to San Francisco that meets all the requirements.”

I held up my hand. “Wait. The Russians, Canadians, and Americans all just do whatever you tell them?”

“Yes. Without question.”

“Are you joshing me with all this?!”

“Get accommodated with your new lab, Dr. Grace. I have other things to deal with.”

She walked out the door without another word.

—

“Yes!” I pump my fist.

I jump to my feet and climb the ladder to the lab. Once there, I climb that ladder and grab hold of the Mystery Hatch.

Just like last time, as soon as I touch the handle, the computer says, “To unlock hatch, state your name.”

“Ryland Grace,” I say with a smug smile. “Dr. Ryland Grace.”

A small click from the hatch is the only response I get. After all the meditation and introspection I did to find out my own name, I wish there’d been something more exciting. Confetti, maybe.

I grab the handle and twist. It turns. My domain is about to grow by at least one new room. I push the hatch upward. Unlike the connector between the bedroom and the lab, this hatch slides to the side. This next room is pretty small, so I guess there wasn’t room for the hatch to swing in. And that next room is…um…?

LED lights flick on. The room is round, like the other two, but it’s not a cylinder. The walls taper inward toward the ceiling. It’s a truncated cone.

I’ve spent the last few days without much information to go on. Now information assaults me from every direction. Every surface is covered with computer monitors and touchscreens. The sheer number of blinking lights

and colors is staggering. Some screens have rows of numbers, others have diagrams, and others just look black.

On the edge of the conical walls is another hatch. This one is less mysterious, though. It has the word stenciled across the top, and the hatch itself has a round window in it. Through the window I can see a tiny chamber—just big enough for one person—with a spacesuit inside. The far wall has another hatch. Yup. That’s an airlock.

And in the center of everything is a chair. It’s perfectly positioned to be able to reach all screens and touch panels easily.

I climb the rest of the way into the room and settle into the chair. It’s comfortable, kind of a bucket seat.

“Pilot detected,” the computer says. “Angular anomaly.” Pilot. Okay.

“Where is the anomaly?” I ask. “Angular anomaly.”

HAL 9000 this computer is not. I look around at the many screens for a clue. The chair swivels easily, which is nice in this 360-degree computer pit. I spot one screen with a blinking red border. I lean in to get a better look.

ANGULAR ANOMALY: RELATIVE MOTION ERROR PREDICTED VELOCITY: 11,423 KPS

MEASURED VELOCITY: 11,872 KPS

STATUS: AUTO-CORRECTING TRAJECTORY. NO ACTION REQUIRED.

Well. That means nothing to me. Except “kps.” That might mean “kilometers per second.”

Above the text is a picture of the sun. It’s jiggling around slightly. Maybe it’s a video? Like a live feed? Or is that just my imagination? On a hunch, I touch the screen with two fingers and drag them apart.

Sure enough, the image zooms in. Just like using a smartphone. There are a couple of sunspots on the left side of the image. I zoom in on those until they fill the screen. The image remains amazingly clear. It’s either an extremely high-resolution photo or an extremely high-resolution solar telescope.

I estimate the cluster of sunspots is about 1 percent the width of the disc. Pretty normal for sunspots. That means I’m now looking at half a degree of the sun’s circumference (very rough math here). The sun rotates about once per twenty-five days (science teachers know this sort of thing). So it should take an hour for the spots to move off the screen. I’ll check back later and see if they have. If so, it’s a live image. If not, it’s a picture.

Hmm…11,872 kilometers per second.

Velocity is relative. It doesn’t make any sense unless you are comparing two objects. A car on the freeway might be going 70 miles per hour compared to the ground, but compared to the car next to it, it’s moving almost 0. So what is that “measured velocity” measuring the velocity of? I think I know.

I’m in a spaceship, right? I have to be. So that value is probably my velocity. But compared to what? Judging by the big ol’ picture of the sun over the text, I’m guessing it’s the sun. So I’m going 11,872 kilometers per second with respect to the sun.

I catch a flicker from the text below. Did something change?

ANGULAR ANOMALY: RELATIVE MOTION ERROR PREDICTED VELOCITY: 11,422 KPS

MEASURED VELOCITY: 11,871 KPS

STATUS: AUTO-CORRECTING TRAJECTORY. NO ACTION REQUIRED.

Those numbers are different! They both went down by one. Oh wow. Hang on. I pull the stopwatch from my toga (the best ancient Greek philosophers always carried stopwatches in their togas). Then I stare at the screen for what seems like an eternity. Just before I’m about to give up, the numbers both drop by one again. I start the timer.

This time, I’m ready for how long the wait will be. Again, it seems interminable, but I stand firm. Finally, the numbers both drop again and I stop the timer.

Sixty-six seconds.

“Measured velocity” is going down by one every sixty-six seconds. Some quick math tells me that’s an acceleration of…15 meters per second per second. That’s the same “gravity” acceleration I worked out earlier.

The force I’m feeling isn’t gravity. And it’s not a centrifuge. I’m in a spaceship that is constantly accelerating in a line. Well, actually it’s decelerating—the values are going down.

And that velocity…it’s a lot of velocity. Yes, it’s going down, but wow! To reach Earth orbit you only need to go 8 kps. I’m going over 11,000. That’s faster than anything in the solar system. Anything that fast will escape the sun’s gravity and go flying off into interstellar space.

The readout doesn’t have anything to indicate what direction I’m going. Just a relative velocity. So now my question is: Am I barreling toward the sun, or away from it?

It’s almost academic. I’m either on a collision course with the sun or on my way out to deep space with no hope of returning. Or, I might be headed in the sun’s general direction, but not on a collision course. If that’s the case, I’ll miss the sun…and then fly off into deep space with no hope of returning.

Well, if the image of the sun is real-time, then the sunspot will get larger or smaller on-screen as I travel. So I just have to wait until I know if it’s real- time. That’ll take about an hour. I start the stopwatch.

I acquaint myself with the million other screens in the little room. Most of them have something to say, but one of them just shows an image of a circular crest. I think it’s probably an idle screen or something. If I touch it, that computer will wake up. But that idle screen might be the most informative thing in here.

It’s a mission crest. I’ve seen enough NASA documentaries to know one when I see one. The circular crest has an outer ring of blue with white text. The text reads across the top and across the bottom. The name and “port of call” for this vessel.

I didn’t think the ship came from somewhere other than Earth, but okay.

Anyway, I guess I finally know the name of this ship I’m on.

I’m aboard the Hail Mary.

Not sure what to do with that information.

But that’s not all the crest has to tell me. Inside the blue band, there’s a black circle with weird symbols inside: a yellow circle with a dot in the middle, a blue circle with a white cross, and a smaller yellow circle with a

lowercase t. No idea what any of that is supposed to mean. Around the edge of the black area it says: “姚,” “ИЛЮХИНА,” and “ ”

The crew.

I’m “Grace,” so those other two must be the names of the mummies in the bunks downstairs. A Chinese person and a Russian person. The memory of them is almost at the surface, but I can’t quite pull it up. I think some internal defense mechanism is suppressing it. When I remember them, it’s going to hurt, so my brain refuses to remember them. Maybe. I don’t know—I’m a science teacher, not a trauma psychologist.

I wipe my eyes clear. Maybe I won’t push too hard for that memory just yet.

I have an hour to kill. I let my mind wander to see what else I can remember. It’s getting easier and easier.

—

“I’m not one hundred percent comfortable with all this,” I said. My voice was muffled by the full hazmat suit I wore. My breath fogged up the clear vinyl face-window thingy.

“You’ll be fine,” said Stratt’s voice over the intercom. She watched from the other side of double-paned, very thick glass.

They’d made a few upgrades to the lab. Oh, the equipment was all the same, but now the entire room was air-sealed. The walls were lined with thick plastic sheets, all held together with some kind of special tape. I saw CDC logos everywhere. Quarantine protocols. Not at all comforting.

The only entry now was through a big plastic airlock. And they made me put on the hazmat suit before going in. An air line led to my suit from a spool in the ceiling.

All the top-of-the-line equipment was ready for whatever I wanted to do. I’d never seen a lab so well stocked. And in the middle was a wheeled cart holding a cylindrical container. Stenciled writing on the cylinder read образец. Not deeply useful.

Stratt wasn’t alone in the observation room. About twenty people in military uniforms stood with her, all looking on with interest. There were

definitely some Americans, some Russians, a few Chinese officers, plus many more unique uniforms I didn’t even recognize. A large international group. None of them said a word, and by some silent agreement, they all stayed a few feet behind Stratt.

I grabbed the air hose with my gloved hand and gestured to Stratt with it. “Is this really necessary?”

She pressed the intercom button. “There’s a very good chance the sample in that cylinder is an alien life-form. We’re not taking any chances.”

“Wait…you’re not taking any chances. But I am!” “It’s not like that.”

“How is it not like that?”

She paused. “Okay, it’s exactly like that.”

I walked to the cylinder. “Did everyone else have to go through all this?”

She looked at the military people and they shrugged at her. “What do you mean by ‘everyone else’?”

“You know,” I said. “The people who transferred it to this container.” “That’s the sample container from the capsule. It’s three centimeters of

lead surrounding a shell of centimeter-thick steel. It’s been sealed since it left

Venus. It has fourteen latches you’ll need to open to get to the sample itself.” I looked at the cylinder, back to her, back to the cylinder, and back to her.

“This is some bull-puckey.”

“Look at the bright side,” she said. “You’ll be forever known as the man who made first contact with extraterrestrial life.”

“If it even is life,” I mumbled.

I got the fourteen latches open with some effort. Those things were tight. I vaguely wondered about how the ArcLight probe closed them in the first place. Must have been some kind of cool actuated system.

The inside wasn’t impressive. I didn’t expect it to be. Just a small, clear, plastic ball that appeared to be empty. The mysterious dots were microscopic and there weren’t very many of them.

“No radiation detected,” Stratt said through the intercom.

I shot a glance over at her. She watched her tablet intensely. I took a good long look at the ball. “Is this under vacuum?”

“No,” she said. “It’s full of argon gas at one atmosphere of pressure. The dots have been moving around the whole time the probe was returning from Venus. So it looks like the argon doesn’t affect them.”

I looked all around the lab. “There’s no glove box here. I can’t just expose unknown samples to normal air.”

“The entire room is full of argon,” she said. “Make sure you don’t kink your air line or rip your suit. If you breathe argon—”

“I’ll suffocate and won’t even know it’s happening. Yeah, okay.”

I took the ball to a tray and carefully twisted it until it came apart in two halves. I placed one half in a sealed plastic container and mopped the other half with a dry cotton swab. I scraped the swab against a slide and took it to a microscope.

I thought they’d be harder to find, but there they were. Dozens of little black dots. And they were indeed wriggling around.

“You recording all this?”

“From thirty-six different angles,” she said.

“Sample consists of many round objects,” I said. “Almost no variance in size—each appears to be approximately ten microns in diameter…”

I adjusted the focus and tried various intensities of backlighting. “Samples are opaque…I can’t see inside, even at the highest available light setting….”

“Are they alive?” Stratt asked.

I glared at her. “I can’t just tell that at a glance. What do you expect to happen here?”

“I want you to find out if they’re alive. And if so, find out how they work.” “That’s a tall order.”

“Why? Biologists worked out how bacteria works. Just do the same thing they did.”

“That took thousands of scientists two centuries to work out!” “Well…do it faster than that.”

“Tell you what”—I pointed back to the microscope—“I’m going to get back to work now. I’ll tell you anything I work out when I work it out. Until then, you can all enjoy some quiet study time.”

I spent the next six hours doing incremental tests. Over that time, the military people wandered out, eventually leaving only Stratt by herself. I had to admire her patience. She sat in the back of the observation room and worked on her tablet, sometimes looking up to see what I was doing.

She perked up as I cycled my way through the airlock and into the observation room. “Got something?” she asked.

I unzipped the suit and stepped out of it. “Yeah, a full bladder.”

She typed on her tablet. “I hadn’t accounted for that. I’ll get a bathroom installed inside the quarantine area tonight. It’ll have to be a chemical toilet. We can’t have plumbing going in and out.”

“Fine, whatever,” I said. I hustled off to the facilities to do my business.

When I returned, Stratt had pulled a small table and two chairs to the center of the observation room. She sat in one of the chairs and gestured to the other. “Have a seat.”

“I’m in the middle of—” “Have a seat.”

I took a seat. She had a commanding presence, that’s for sure. Something about her tone of voice or her general confidence level, maybe? One way or another, when she spoke you just kind of assumed you should do what she said.

“What have you found so far?” she asked. “It’s only been one afternoon,” I said.

“I didn’t ask how long it’s been. I asked what you’ve found out so far.”

I scratched my head. After hours in that suit, I was sweaty and presumably smelled bad. “It’s…weird. I don’t know what those dots are made of. And I’d really like to know.”

“Is there some equipment you need that you don’t have?” she asked.

“No, no. There’s everything a guy could hope for in there. It just…doesn’t work on these dots.” I settled back into the chair. I’d been on my feet most of the day and it was nice to relax for a moment. “First thing I tried was the x- ray spectrometer. It sends x-rays into a sample, making it emit photons and you can tell from the wavelengths of the photons what elements are present.”

“And what did that tell you?”

“Nothing. As far as I can tell, these dots just absorb x-rays. The x-rays go in and they never come out. Nothing comes out. That’s very odd. I can’t think of anything that does that.”

“Okay.” She took some notes on her tablet. “What else can you tell me?” “Next I tried gas chromatography. That’s where you vaporize the sample

and then identify the elements or compounds in the resulting gas. That didn’t

work either.” “Why not?”

I threw up my hands. “Because the darn things just won’t vaporize. That led me down a rabbit hole of burners, ovens, and crucible furnaces that turned up nothing. The dots are unaffected at temperatures up to two thousand degrees Celsius. Nothing.”

“And that’s odd?”

“It’s crazy odd,” I said. “But these things live on the sun. At least some of the time. So I guess having a high resistance to heat makes sense.”

“They live on the sun?” she said. “So they’re a life-form?” “I’m pretty sure they are, yeah.”

“Elaborate.”

“Well, they move around. It’s plainly visible through the microscope. That alone doesn’t prove they’re alive—inert stuff moves all the time from static charge or magnetic fields or whatever. But there is something else I noticed. Something weird. And it made the pieces fall into place.”

“Okay.”

“I put a few dots under a vacuum and ran a spectrograph. Just a simple test to see if they emit light. And they do, of course. They give off infrared light at the 25.984 micron wavelength. That’s the Petrova frequency—the light that makes the Petrova line. I expected that. But then I noticed they only emit light when they’re moving. And boy, do they emit a lot of it. I mean, not a lot from our point of view, but for a tiny single-celled organism it’s a ton.”

“And how is that relevant?”

“I did some back-of-the napkin math. And I’m pretty sure that light is how they move around.”

Stratt raised an eyebrow. “I don’t follow.”

“Believe it or not, light has momentum,” I said. “It exerts a force. If you were out in space and you turned on a flashlight, you’d get a teeny, tiny amount of thrust from it.”

“I didn’t know that.”

“Now you do. And a teeny-tiny thrust on a teeny-tiny mass can be an effective form of propulsion. I measured the dots’ average mass at about twenty picograms. That took a long time, by the way, but that lab equipment is awesome. Anyway, the movement I see is consistent with the momentum of the emitted light.”

She set her tablet down. I had, apparently, accomplished the rare feat of getting her undivided attention. “Is that something that happens in nature?”

I shook my head. “No way. Nothing in nature has that kind of energy storage. You don’t understand how much energy these dots are emitting. It’s like…getting to the scales of mass conversion. E = mc2 kind of stuff. These tiny dots have more energy stored up in them than remotely makes sense.”

“Well,” she said. “They did just come from the sun. And the sun is losing energy.”

“Yeah. That’s why I think it’s a life-form,” I said. “It consumes energy, stores it in some way we don’t understand, then uses it for propulsion. That’s not a simple physical or chemical process. That’s complex and directed. Something that must have evolved.”

“So the Petrova line is…tiny little rocket flares?”

“Probably. And I bet we’re only seeing a small percentage of the total light coming off that area. They use it to propel themselves to Venus or to the sun. Or both. I don’t know. Point is, the light will go away from their direction of travel. Earth isn’t in that line, so we only see the light that reflects off nearby space dust.”

“Why do they go to Venus?” she asked. “And how do they reproduce?” “Good questions. Ones I don’t have answers for. But if they’re single-celled

stimulus/response organisms, they probably reproduce through mitosis.” I

paused. “That’s when the cell splits in half to become two new cells—”

“Yes, I know that much, thank you.” She looked to the ceiling. “People always assumed our first contact with alien life—if any existed—would be

little green men in UFOs. We never considered the idea of a simple, unintelligent species.”

“Yeah,” I said. “This isn’t Vulcans dropping by to say hi. This is…space algae.”

“An invasive species. Like cane toads in Australia.”

“Good analogy.” I nodded. “And the population is growing. Fast. The more of them there are, the more solar energy gets consumed.”

She pinched her chin. “What would you call an organism that exists on a diet of stars?”

I struggled to remember my Greek and Latin root words. “I think you’d call it ‘Astrophage.’ ”

“Astrophage,” she said. She typed it into her tablet. “Okay. Get back to work. Find out how they breed.”

—

Astrophage!

The word alone makes all my muscles clinch up. A chilling terror that hits like a lead weight.

That’s the name. The thing that threatens all life on Earth. Astrophage.

I glance at the monitor with my zoomed-in image of the sun. The sunspots have moved noticeably. Okay, it’s a real-time image. Good to know.

Waaaaait…I don’t think they’re moving at the right speed. I check the stopwatch. I was only daydreaming for ten minutes or so. The sunspots should have moved a fraction of a degree. But they’re halfway off the screen. Way more than they should have moved.

I pull the tape measure from my toga. I zoom out the image and actually measure the widths of the sun and sunspot cluster on the screen. No more rough estimates. I want real math here.

The solar disc is 27 centimeters on-screen and the sunspots are 3 millimeters. And they moved half their width (1.5 millimeters) in ten minutes. Actually, it was 517 seconds, according to my stopwatch. I scribble some math on my arm.

At this resolution, they’re moving 1 millimeter every 344.66 seconds. To cross the entire 27 centimeters it would take (scribble, scribble) just over 93,000 seconds. So it’ll take that long for the cluster to cross the near side of the sun. It’ll take twice that long to get all the way around. So 186,000 seconds. That’s a little over two days.

Over ten times faster than the rotation should be. This star I’m looking at…it’s not the sun.

I’m in a different solar system.