End of an Era

Broadly speaking, Earth looked much as it did from modern space photos: a blue ball covered with twists of cottony whiteness. My eyes finally got used to the scale of the planet and began to make sense of the partially obscured continents. Their shapes had changed over the millennia, but I knew enough about tectonic drift to easily figure out which was which. There was Antarctica, a tiny white splotch much smaller than it is in the twenty-first century. Just splitting from it was Australia, turned at an odd angle. India was moving freely across the Tethys Ocean on its way toward its inevitable impact with Asia, the event that would push up the Himalayas. South America had only just begun to pull away from Africa, the perfect jigsaw-puzzle fit of their coastlines obscured slightly by a seaway that ran from where the Sahara Desert would one day be to the Gulf of Guinea. Another giant seaway, broken only by a long north-south archipelago, separated Europe from Asia. Between South America and North America was open ocean, thousands of times wider than the Panama Canal would one day be. Still, the Gulf of Mexico was clearly visible, and -

Christ.

Jesus Christ.

"Klicks!" I shouted.

"What?" said his voice.

"Look at the Gulf of Mexico!"

"Yeah?"

"Look at it!"

"I don’t—"

"It’s all on dry land," I said, "not half-submerged as it will be in our time, but, look — it’s already there."

"What are you ta — oh. Oh, my God…" Klicks’s voice was full of astonishment.

"Het!" I called out, wishing I had a name to use. "Het! Any Het!"

"Yes?" came the emaciated voice of a brachiator.

"How long has that crater been there?"

"Which crater?"

"The one on the rim of that large gulf at the southern end of the landmass we took off from. See it? It’s about a hundred and fifty kilometers in diameter…" I wasn’t that good at estimating distances from this high up, but I knew how big it had to be.

"Oh, that crater," said the voice, each word a distinct, separate sound. "It formed about ninety of our years ago — two hundred or so of yours."

"You’re sure?" asked Klicks’s voice.

"We had tracked the asteroid that made that crater. For a brief time we thought it might pass near Mars; as you may know, our two moons were once asteroids, captured by our gravity. But it did not come particularly close to us; instead, it struck your planet. The explosion was visually spectacular."

"But … but…" Klicks was trying to make sense of it. "But the impact that made that crater is what we’d thought had killed off the dinosaurs."

"An incorrect assumption," said the Martian, simply. "After all, the dinosaurs live on."

The best resolution in the geologic record this far back was maybe ten thousand years, and that only under extraordinary circumstances; a hundred thousand was much more common. Events that had occurred centuries or even millennia apart could easily seem simultaneous.

"The impact must have had a big effect on the biosphere, though," said Klicks, a note of desperation in his voice. I felt myself grinning from ear to ear.

"Not really," said the Het. "Those plants and animals at the crater site were destroyed, of course, but the worldwide effect was negligible." It paused. "Your people and mine inhabit the same messy solar system. Impacts happen — surely you know that. But life goes on."

I wished I could see the look on Klicks’s face — but all I could see was the glorious planet below. We were whisking back toward the night, the terminator hurrying toward us. Our view swung back up to look at the stars. There were so many that discerning any pattern, anything that one might call a constellation, seemed impossible. I enjoyed the spectacle; Klicks had been in line to possibly go to Mars, but I’d never dreamed that I would see the stars from space. The sight was magnificent, breathtaking, truly the most beautiful thing I’d ever seen, and -

"What’s that?" Klicks’s voice intruded again from the outside world.

I scanned the heavens, trying to find whatever had caught his eye. There, far down in the southern sky: a tight rosette of brilliant blue points. I watched it as we swung around. The points didn’t shift at all in relation to the background stars as we continued in our orbit, meaning they weren’t nearby.

"What is that?" Klicks said again.

"What" "is" "what?" The reedy voice of the brachiator.

"That cluster of lights," said Klicks. "What is it?"

"We do not speak of it."

"You must know what it is."

"We do not."

"Is it in this solar system?"

"No. It is some three-to-the-fifth light-years away. Clarification: Martian light-years, and two hundred forty-three of them in your counting. About double that in Earth light-years."

"Then what is it?"

"It’s a beacon, isn’t it?" I said, surprising myself. "A visual signal to the rest of the galaxy that there’s intelligent life there." The rosette was beautiful, with mathematically precise construction. "Look at it: the points are arranged in a geodesic. It’d look like a sphere from any angle. It has to be artificial."