I, on the other hand, needed real food. Susan had packed me a can of strawberry-banana Boost and two leftover drumsticks from yesterday’s dinner. I downed the thick beverage and made it halfway through one of the legs. I wished I’d had something different to eat; it felt a little too primal to be using my teeth to tear meat off bones in front of the alien, although, for all I knew, Hollus was stuffing live hamsters into his gullet.

While we ate, Hollus and I watched the videos Abdus had fetched; I’d had the education department deliver a combo VCR-TV unit to my office.

First up was “Arena,” an episode of the original Star Trek series; I immediately froze the image on a picture of Mr. Spock. “See him?” I said. “He’s an alien — a Vulcan.”

“He” “looks” “like” “a” “human” “being,” said Hollus; he could eat and talk at the same time.

“Notice the ears.”

Hollus’s eyestalks stopped weaving in and out. “And that makes him an alien?”

“Well,” I said, “of course it’s a human actor playing the part — a guy named Leonard Nimoy. But, yeah, the ears are supposed to suggest alienness; this show was done on a low budget.” I paused. “Actually, Spock there is only half-Vulcan; the other half is human.”

“How is that possible?”

“His mother was a human; his father was a Vulcan.”

“That does not make sense biologically,” said Hollus. “It would seem more likely that you could crossbreed a strawberry and a human; at least they evolved on the same planet.”

I smiled. “Believe me, I know that. But wait, there’s another alien in this episode.” I fast-forwarded for a time, then hit the play button again.

“That’s a Gorn,” I said, pointing to the tailless green reptile with compound eyes wearing a gold tunic. “He’s the captain of another starship. Pretty neat, huh? I always loved that one — reminded me of a dinosaur.”

“Indeed,” said Hollus. “Which means, again, that it is far too terrestrial in appearance.”

“Well, it’s an actor inside a rubber suit,” I said.

Hollus’s eyes regarded me as if I were again being Master of the Bleeding Obvious.

We watched the Gorn stagger around for a bit, then I ejected the tape and put in “Journey to Babel.” I didn’t fast-forward, though; I just let the teaser unfold. “See them?” I said. “Those are Spock’s parents. Sarek is a full-blooded Vulcan, and Amanda, the woman there, is a full-blooded human.”

“Astonishing,” said Hollus. “And humans believe such crossbreeding is possible?”

I shrugged a little. “Well, it’s science fiction,” I said. “It’s entertainment.” I fast-forwarded to the diplomatic reception. A stocky snout-nosed alien accosted Sarek: “No, you,” he snarled. “How do you vote, Sarek of Vulcan?”

“That’s a Tellarite,” I said. Then, remembering: “His name is Gay.”

“He looks like one of your pigs,” said Hollus. “Yet again, too terrestrial.”

I fast-forwarded some more. “That’s an Andorian,” I said. The screen showed a blue-skinned, white-haired male humanoid, with two thick, segmented antennae emerging from the top of his head.

“What is his name?” asked Hollus.

It was Shras, but for some reason I was embarrassed that I knew that. “I don’t remember,” I said, then I put in another tape: the special-edition version of Star Wars, letterboxed. I fast-forwarded to the cantina sequence. Hollus liked Greedo — Jabba’s insectlike henchman who confronted Han Solo — and he liked Hammerhead and a few of the others, but he still felt that humanity had missed the boat on coming up with realistic portrayals of extraterrestrial life. I certainly didn’t disagree.

“Still,” said Hollus, “your filmmakers did get one thing right.”

“What’s that?” I asked.

“The diplomatic reception; the scene in the bar. All the aliens shown seem to have about the same level of technology.”

I furrowed my brow. “I always thought that was one of the least believable things. I mean, the universe is something like twelve billion years old—”

“Actually, it is 13.93422 billion,” said Hollus, “measured in Earth years, of course.”

“Well, fine. The universe is 13.9 billion years old, and Earth is only 4.5 billion years old. There must be planets much, much older than ours, and much, much younger. I’d expect some intelligent races to be millions if not billions of years more advanced than we are, and some to be at least somewhat more primitive.”

“A race even a few decades less advanced than you are would not have radio or spaceflight and therefore would be undetectable,” said Hollus.

“True. But I’d still expect lots of races to be much more advanced than we are — like, well, like yourself, for instance.”

Hollus’s eyes looked at each other — an expression of surprise? “We Forhilnors are not greatly advanced beyond your race — perhaps a century at most; certainly no more than that. I expect that within a few decades your physicists will make the breakthrough that will allow you to use fusion to economically accelerate ships to within a tiny fraction of the speed of light.”

“Really? Wow. But — but how old is Beta Hydri?” It would be quite a coincidence if it were the same age as Earth’s sun.

“About 2.6 billion Earth years.”

“A little over half as old as Sol.”

“Sol?” said Hollus’s left mouth.

“That’s what we call our sun, when we want to distinguish it from other stars,” I said. “But if Beta Hydri is that young, I’m surprised that you have any vertebrates on your world, let alone any intelligent life.”

Hollus considered this. “When did life first emerge on Earth?”

“We certainly had life by 3.8 billion years ago — there are fossils that old — and it may have been here as far back as four billion years ago.”

The alien sounded incredulous. “And the first animals with spinal columns appeared just half a billion years ago, no? So it took perhaps as much as 3.5 billion years to go from the origin of life to the first vertebrates?” He bobbed his torso. “Life originated on my world when it was 350 million years old, and vertebrates appeared just 1.8 billion years later.”

“I wonder why it took so much longer here?”

“As I told you,” said Hollus, “the development of life on both our worlds was manipulated by God. Perhaps his or her goal was to have multiple sapient lifeforms emerge simultaneously.”

“Ah,” I said dubiously.

“But, even were that not true,” said Hollus, “there is another reason for all space-faring races to be comparably advanced.”

Something was tickling at the back of my mind, something I’d once seen Carl Sagan explain on TV: the Drake equation. It had several terms, including the rate of star formation, the fraction of stars that might have planets, and so on. By multiplying all the terms together, you were supposed to be able to guesstimate the number of intelligent civilizations that might currently exist in the Milky Way. I can’t remember all the terms, but I do remember the final one — because it chilled me when Sagan discussed it.

The final term was the lifetime of a technological civilization: the number of years between the development of radio broadcasting and the extinction of the race. Humans had first started broadcasting in earnest in the 1920s; if the Cold War had turned hot, our tenure as a technological species might have been as little as thirty years.

“You mean the lifetime of a civilization?” I said. “The span before it blows itself up?”

“That is one possibility, I suppose,” said Hollus. “Certainly, my own race had a difficult time learning to use nuclear power wisely.” The alien paused. “I am given to understand that many humans suffer from mental problems.”

I was startled by the apparent change of topic. “Umm, yes. I suppose that’s true.”

“As do many Forhilnors,” said Hollus. “It is another concern: as technology advances, the ability to destroy the entire race becomes more accessible. Eventually, it is in the hands not just of governments but also individuals — some of whom are unbalanced.”