I nodded, knowing no matter how realistic and accurate the reconstructions might be, they would never be the same as the originals. “Thank you.”

“It is a terrible loss,” Hollus said. “I have never seen fossils of that quality on any other world. They were really quite—”

She broke off in mid-sentence, and her simulacrum froze in place, as if the real Hollus, the one in synchronous orbit aboard the mothership, had been distracted by something happening up there.

“Hollus?” I said, not really concerned; one of her shipmates was probably just asking her a question.

“Just a moment,” she replied, the simulacrum moving again. I heard a few songs in the Forhilnor language as she communicated with somebody else, and then the simulacrum froze once more.

I sighed impatiently. This was worse than Call Waiting: you still had the damned simulacrum taking up most of your office. I picked up a magazine off my desk — the latest New Scientist; the departmental copy started its circulation with me and worked its way down through the ranks. I’d only just opened its cover when the Hollus avatar started moving again. “Terrible news,” she said, one word per mouth, her voices oddly attenuated. “I — my God, it is terrible news.”

I dropped the magazine. “What?”

Hollus’s eyestalks were swinging back and forth. “Our mothership does not have to contend with the scattering of light by your planet’s atmosphere; even during daytime, the Merelcas’s sensors can still clearly see the stars. And one of those stars . . .”

I leaned forward in my chair. “Yes? Yes?”

“One of those stars has begun its conversion to a — what is the word, again? When a massive star explodes?”

“A supernova?” I said.

“Yes.”

“Wow.” I remembered all the excitement around the planetarium back in 1987 when the U of T’s Jan Shelton discovered the supernova in the Large Magellanic Cloud. “That’s great.”

“It is not great,” said Hollus. “The star that has begun to explode is Alpha Orionis.”

“Betelgeuse?” I said. “Betelgeuse has started going supernova?”

“That is correct.”

“Are you sure?”

“There can be no doubt,” said the Forhilnor, her two voices sounding quite shaky. “It is already shining with more than a million times its normal brightness, and its luminosity is still increasing.”

“My God,” I said. “I — I should phone Donald Chen. He’ll know who to notify. There’s a central bureau for astronomical telegrams, or some such thing . . .” I picked up my phone and dialed Chen’s extension. He answered on the third ring; one more and his voice mail would have picked up.

“Don,” I said, “it’s Tom Jericho. Hollus here tells me that Betelgeuse has just gone supernova.”

There was silence for a few moments. “Betelgeuse is — was — a prime candidate to go supernova,” he said. “But no one knew precisely when it would happen.” A pause, and then, earnestly, as if he just realized something: “Did Hollus say Betelgeuse? Alpha Orionis?”

“Yes.”

“Look, is Hollus sure? Absolutely sure?”

“Yes, she says she’s positive.”

“Damn,” said Chen into his phone’s mouthpiece, but I don’t think he was really talking to me. “Damn.”

“What?” I said.

Chen’s voice sounded strained. “I’ve been going over that supernova data Hollus sent down, particularly as related to gamma-ray output. For the last supernova, the one in 1987, we had lousy data; it happened before we had any dedicated gamma-ray observation satellites — Compton didn’t go up until 1991. The only gamma-ray data we had for Supernova 1987A was from the Solar Maximum Mission satellite, and it wasn’t designed for extragalactic observations.”

“So?”

“So the gamma-ray output of a supernova is much greater than we’d thought; Hollus’s data proves that.”

“And?” I said. “What does that mean?” I looked over at Hollus, who was bobbing extremely rapidly; I’d never seen her so upset.

Chen let out a long sigh, the sound rumbling across the phone line. “It means that our atmosphere is going to be ionized. It means that the ozone layer is going to be depleted.” He paused. “It means that we’re all going to die.”

Ricky Jericho was many kilometers north of the ROM, in the playground at Churchill Public School. It was the middle of the ninety-minute lunch break; some of his classmates went home for lunch, but Ricky ate at school in a room where they let the kids watch The Flintstones on CFTO. After he’d finished his bologna sandwich and apple, he’d gone out into the grassy yard. Various teachers were walking around, breaking up fights, cooing over skinned knees, and doing all the other things teachers had to do. Ricky looked at the sky. Something was shining brightly up there.

He made his way past the jungle gym and found his teacher. “Miss Cohan,” he said, tugging at her skirt. “What’s that?”

She used a hand to shield her eyes as she looked up in the direction he was pointing. “That’s just an airplane, Ricky.”

Ricky Jericho wasn’t one to contradict his teachers lightly. But he shook his head. “No, it’s not,” he said. “It can’t be. It’s not moving.”

My mind was swirling, and my intestines were knotting. A new day was dawning, not just in Toronto, but for the entire Milky Way. In fact, even observers in far-distant galaxies would surely see the growing brightness once sufficient time had elapsed for the light to reach them. It beggared the imagination. Betelgeuse was indeed going supernova.

I put Don on the speaker phone, and he and Hollus conversed back and forth, with me interjecting the occasional worried question. What was happening, I gathered, was this: in every active star, hydrogen and helium undergo fusion, producing successively heavier elements. But, if the star is sufficiently massive, when the fusion chain reaches iron, energy starts being absorbed rather than released, causing a ferrous core to build up. The star grows too dense to support itself: the outward explosive thrust of its internal fusion no longer counteracts the huge pull of its own gravity. The core collapses into degenerate matter — atomic nuclei crushed together, forming a volume only twenty kilometers across but with a mass many times that of Sol. And when infalling hydrogen and helium from the outer layers of the star suddenly hit this new, hard surface, they fuse instantly. The fusion blast and the shockwave of the collision propagate back out, blowing off the star’s gaseous atmosphere and releasing a torrent of radio noise, light, heat, x rays, cosmic rays, and neutrinos — a deadly sleet pouring out in all directions, an expanding spherical shell of death and destruction shining brighter than all the other stars in the galaxy combined: a supernova.

And that, apparently, was happening right now to Betelgeuse. Its diameter was expanding rapidly; within days, it would be bigger than Earth’s entire solar system.

Earth would be protected for a time: our atmosphere would keep the initial onslaught from reaching the ground. But there was more coming. Much more.

I’d tuned the radio in my office to CFTR, an all-news station. As reports started appearing on Earth’s TV and radio stations, some people rushed to caves and mine shafts. It wouldn’t make any difference. The end of the world was coming — and with a bang, not a whimper.

Those Forhilnors and Wreeds currently visiting Earth, perhaps along with a few human passengers, might escape, at least for a time; they could maneuver their starship to keep the bulk of the planet between themselves and Betelgeuse, acting as a shield of stone and iron almost thirteen thousand kilometers thick. But there was no way they could outrun the expanding shell of death; it would take the Merelcas a full year to accelerate to close to the speed of light.

But even if that ship could escape, the Forhilnor and Wreed homeworlds could not; they would soon be facing the same onslaught, the same scourge. The asteroids that hit Sol III and Beta Hydri III and Delta Pavonis II sixty-five million years ago were minor blows in comparison, mere flesh wounds from which the ecosystems rebounded within a matter of decades.