A strange interstellar object is coming to Earth in this excerpt from The Last Astronaut

Preflight Check

Sunny had given this presentation multiple times. The first time, when he’d talked to McAllister’s boss — NASA’s administrator, the head honcho — it took ninety minutes to get through. When he gave the same talk to NASA’s advisory groups, then the mission directorates and the staff offices, he’d gotten down to a tight twenty. Then one day they’d put him in front of a 3-D camera and told him he would be speaking directly to the president of the United States. That time he’d been given five minutes.

Now he was giving the talk one last time. They promised. He was still a ball of nerves as he headed to classroom six at JPL and loaded all his files into the screen on the podium. Whom could they possibly be bringing in this time? The secretary-general of the UN? The classroom could hold 120 people. Today only four came in and sat down in the big stadium-style chairs. Two of them sat down in the middle rows, a couple of seats apart from each other. A Southeast Asian woman in a cardigan and some military guy with tons of medals on the front of his uniform. He took his hat off and carefully sat it on the seat next to him. Sunny caught the woman’s eye and smiled. She gave him back a very fast, tight little smile, then leaned forward and hugged her knees, as if she was very nervous. Maybe she had some idea of what he was going to say.

Two more people came in and sat down in the front row. Roy McAllister and a middle-aged woman wearing a pair of cheap AR sunglasses. It took Sunny a minute to realize whom he was looking at.

“Wait,” he said. “ Wait — she’ s — you’ re —”

“Clearly you recognize Ms. Jansen,” McAllister said. “So let me introduce you. Everyone, this is Sunny Stevens. He’s an astrophysicist working in our Planetary Science Directorate. He may look young, but don’t let that fool you. He’s well on his way to his first Nobel. Most likely for the discovery he’s going to tell you about today.”

Sunny nodded, barely listening. It was her. Sally Jansen, looking right at him.

The woman who’d killed Blaine Wilson. The woman who’d lost the race for Mars. What the hell was she doing here? This was top-secret stuff, not meant for every washed-up astronaut NASA could drag in off the street —

“We’re a bit tight on time, Dr. Stevens,” McAllister said. “Perhaps we could . . . ?”

Sunny nodded and exhaled deeply. He was a little thrown, but he could do this. He knew it all by heart. He just wished — he wished Jansen would take those sunglasses off. Who still wore AR sunglasses? Everybody in his generation just used an earring or a nose ring as their device. The sunglasses made it impossible to see her eyes. To know what she was thinking.

Still, she was just one more person he needed to convince. Sunny knew what was at stake with these presentations. He tapped the screen on the podium and got started.

Light bloomed above them as an AR image formed, pixels coalescing out of the air.

“This,” he said, gesturing at the air above their heads, “is an object called 1I/2017 U1. Also known as ‘Oumuamua, which is a Hawaiian word meaning ‘first messenger.’ ”

In augmented reality the object turned lazily on its short axis. It didn’t look like much, honestly. It was a cigar-shaped lump of rock, a dull red in color. The image was heavily pixelated. “We never got a really good look at it. It came into the solar system way back, in 2017, long before I was born, and, uh . . .”

It occurred to him that some of the people listening to him were old enough to remember 2017. They sat there looking like lumps of rock themselves. He brushed off the thought and went on.

“It was just another rock, right, a piece of space debris, not even big enough to worry about.” Scale bars appeared around the image, showing that ‘Oumuamua was thirty-five meters across and 230 long. “They couldn’t even figure out what it was, back then. Whether it was an asteroid or a comet. There was one thing about it, though, that got a lot of attention. It didn’t come from our solar system.”

The image zoomed out to show the track ‘Oumuamua had taken around the sun. It dove out of deep space almost perpendicular to the plane of the ecliptic — the plane around the sun’s equator where all the planets orbited. Moving very, very fast it swung around the sun, looping around to shoot off at a new angle that sent it past the inner planets and then, eventually, back out into deep space.

“We still don’t know where it came from. Maybe somewhere around the star Vega. But yeah — it came from out there. Out there in the galaxy.” As he warmed up, Sunny had to fight the urge to bounce up and down on the stage. This is where it got very interesting. “It passed through interstellar space — it might have been out there for a hundred thousand years or more. Then it very briefly passed through our solar system before heading back out into the dark. Our telescopes weren’t great back then, and we barely got a look at it. But it changed — well, a whole lot of things in astronomy. It made us really think, for the first time, about what else was out there.”

He tapped the screen, and ‘Oumuamua’s path traced a white curve around the sun. He tapped the screen again, and a second curve appeared.

“In astronomy, if you see one specimen of a new type of object, you know you’ll find more of them if you look. The universe is so big there are very few unique things in it. We had to assume it wasn’t the only interstellar rock out there. Back in ’17, KSpace was still working on launching their first rocket, but already they had a strong interest in astronomy. They set up a radio telescope survey to look for more I objects. About three years ago I took over that project. Specifically, I created a new search pattern that focused on the part of the sky where ‘Oumuamua originated. I figured if one rock came from that direction, maybe more of them would come from the same place. It turns out I was right.”

The second white curve traced almost exactly the same arc as the first. “This is 2I/2054 D1.” He couldn’t help but beam out at his sparse audience. “My baby.”

He turned and watched the white curves, entranced as always by the cosmic duet.

“If ‘Oumuamua was weird, so was 2I, and in all the same ways. It has the same deep-red color. It’s the same basic cigar shape, about eight times as long as it is wide. That was enough to pique my interest. But then I used a light curve analysis to get a better idea of its size.”

A graphic representation of ‘Oumuamua appeared as a small spindly shape floating in front of the screen. A tiny blur of low-resolution pixels. 2I appeared above it — and dwarfed it.

“2I is about three hundred and fifty times bigger than ‘Oumuamua. Identical in almost every single way, except on a massively larger scale. I’ve estimated it’s about ten kilometers across and eighty kilometers long. And it’s currently headed toward us, eating up twenty-six kilometers every second.”

Sally Jansen coughed for his attention. “That sounds fast,” she said. “Too fast.”

Sunny gave her a tentative smile. At least she was paying attention. “Oh yeah,” he said. “And that’s why 2I is super interesting. Both of them, ‘Oumuamua and 2I, they came at us about the same speed. Interstellar speed, call it. Most comets, even the really fast ones, top out at about five kilometers per second. The fastest spacecraft ever built — Voyager 2 — is moving about fifteen kilometers a second. There’s one difference, though. Comets and planets and everything natural will keep the same speed pretty much forever, right? We know the laws of physics, and how they apply to big, dumb objects moving through space. ‘Oumuamua followed all those rules. It came in super fast. Then it sped up as it swung around the sun, which makes sense; it used the sun’s gravity to get the slingshot effect, to speed itself up. Originally,” he said, pointing at the white curves above his head, “we thought 2I would do the same thing. Swing around the sun, build up a good head of steam, and head back out for the stars, so fast we would barely get a look at it. That’s what I was expecting — what everybody was expecting. Except then it didn’t.”

He tapped the screen. His heart was pounding in his chest. This was the thing he needed to explain. The reason he kept giving this presentation.

“It slowed down,” Stevens announced. “Decelerated. The last time I checked, it was down to about twenty-one kilometers per second, and it’s still slowing. It shouldn’t be doing that. I mean, there are reasons why an astronomical body might decelerate, sure. Drag or a collision with another object or . . . whatever, but none of them fit. 2I wasn’t acting like a normal space rock, but what did that mean? Then it went and answered the question for us. It changed course.”

On the screen the white curve bent inward on itself, moving away from the sun. “With no physical explanation, it started moving in a direction we didn’t expect.” The white curve made a delicate, graceful arc toward the plane of the ecliptic — and the orbits of the planets. One planet in particular.

“It’s headed towards Earth,” Stevens said. “If it continues on its present course and deceleration, in about six months it’ll pass inside the orbit of the moon. By that point it’ll have slowed down to less than eleven kilometers per second. In other words, less than Earth’s escape velocity.

“To me,” Sunny said, “this looks like a classic Hohmann transfer orbit.” He waved at the screen, and the trajectory continued as a dashed line. The view zoomed in so they could see the curve bending around the surface of Earth. “This is just speculation, but I’m thinking it’s going to eventually execute another course correction, one using very little delta-v. A minimum expenditure of thrust. With just a little nudge, it could enter a polar orbit of the Earth.”

Jansen leaned forward in her seat. The AR simulation was good enough Sunny could see the white curves crisscrossing the black lenses of her sunglasses.

“Comets and asteroids don’t act like that,” she said. “What you’re saying —”

Sunny did bounce up and down a little then. He shoved his hands in his pockets because he didn’t know what else to do with them.

“It’s not a comet or an asteroid. It’s a spaceship. It’s a spaceship moving under its own power.”

“And if it’s coming from deep space — that means it’s a starship,” McAllister said, softly. “An alien craft.”

ROY MCALLISTER, ASSOCIATE ADMINISTRATOR FOR EXPLORATION AND OPERATIONS, NASA: We attempted to make contact with 2I every way we knew how. We had a team from the SETI Institute design a series of radio signals that would indicate our presence, our intelligence, and our desire to communicate. We used the most powerful radio transmitters in the world to send the signals, repeating the message hundreds of times a day. There was no response, not even an acknowledgment that the aliens had got our call. We needed to know — as soon as physically possible — what its intentions were. It wasn’t an academic question. It was possible that 2I intended to take up orbit around Earth. It was also possible it was sent to crash right into us. An object that large, moving at that velocity, would wipe out all life on the planet. I took Dr. Stevens’s presentation to every government scientific and political body that would listen. I found a lot of doors open to me — it didn’t take an astrophysicist to understand how important this was.