There were a good many theoretical problems in science that made them itch to learn the answers. What was the truth, they wanted to know, behind the “missing mass”—the fact that all the observable matter in the universe did not seem to weigh enough to account for the observed motion of galaxies? Did protons really decay? Was there something before the Big Bang, and if so, what?
Human scientists worried about all these questions, too, in the days before we met the Heechee. The Heechee had a big advantage over those early humans (my meat progenitor included). They could go out and take a look.
So they did. They sent out expeditions to study novae and supernovae and neutron stars and white dwarfs and pulsars. They measured the flow of matter between pairs of close binaries, and they metered the flux of radiation from the infall of gas around black holes. They even learned to look inside the Schwarzschild barrier around black holes, a trick which led to some useful technology later on; and I do not even speak of their equally great curiosity about the ways particles fit together to make atoms, atoms joined into molecules, and molecules became living things like themselves.
I can easily summarize exactly what it was that the Heechee wanted in the way of knowledge. They wanted it all.
But of all their quests none was more urgent, or more assiduously pursued, than the search for inteffigent life in the universe other than their own.
Over time, the Heechee found a couple of examples-or almost did. The first was a chance discovery that brought quick joy and almost instant disappointment. A small, icy planet, hardly worth a second look in the normal course of events, surprised them by showing some curious anomalies in its magnetic field. No one was greatly interested at first. Then, on a routine sweep, a Heechee-manned exploration ship checked out the reports from the instrument-only robot investigators. The planet was more than 200 AU from its parent not-very-bright K-3 star, certainly not the sort of place where you would expect life to develop. Its surface temperature was only about 200 K and nothing stirred on its glacial surface. But when the Heechee investigators sounded the ice, they found great masses of metal buried in it. Echoes showed the metal to be in regular shapes. When, excitedly, the crew called for thermal borers and sent them down to investigate, they found buildings! Factories! Machines!
And nothing living at all.
They faced the disheartening fact that once there had been intelligent life on that planet, well up to early industrial standards by the remnants they disinterred, but it was there no longer.
Dating the ice cores showed that they were half a million years too late to find anyone alive, and that wasn’t the worst of it. The worst was a finding by the geologists and geochemists that said, inarguably, that that particular planet could not have evolved in that particular orbit; its composition was like that of Venus, the Earth, and Mars, the kind found only close to a primary.
Something had hurled it so far from its sun that it froze.
Of course, it could have been some astronomical accident like the (however statistically unlikely) near passage of another star. But none of the Heechee could believe that (though they wanted to).
Then they found the second heartbreak.
It wasn’t a heartbreak at once. It was a bright hope that persisted for a long time-more than a century! It began when a Heechee vessel caught the scent of a radio transmission, tracked it down, and found a genuine, incontestable artifact of a highly technological civilization traveling through interstellar space.
It did not have a living crew. It couldn’t have, except perhaps for microbes. The object was a vast, gossamer, metal spiderweb, a thousand kilometers across but so fairy-silk flimsy that the whole thing weighed less than a fingernail.
It did not take the Heechee long to realize what they had. Where the wires joined were transistor-like things and strips of piezoelectric materials. The object was a calculator. It was also a computer, a camera, a radio transmitter, all wonderfully crafted into a gauzy web you could crush into the palm of your hand.
It was a robot sailship, propelled by light.
The proof was certain: There was intelligent life in the universe like the Heechee themselves! Not just intelligent life; it was technological life, starfaring life. They understood at once that this was an ultralight interstellar probe, a starwisp, drifting out to explore the Galaxy by radiation pressure, surveying other stars and reporting back by radio to its makers on their home planet.
But where was the home planet?
The Heechee ship had unfortunately failed to measure the precise alignment of the web when they captured it. Though they knew within a few degrees of where it had pointed, those few degrees encompassed some hundred million stars, far and near.
So for the next century, every Heechee ship that went into space, wherever bound, carried a dedicated radio receiver. It was always on, and it did nothing but listen for the song of another of those starwisps.
And they found them.
The first one was damaged, its orientation no longer perfect-but even that limited the choices to only about a million stars, an improvement of two orders of magnitude. And then they found a fine new one, in perfect working order, zeroed in precisely.
Swarms of Heechee explorers pounced on that corner of the Galaxy. There were still a lot of stars to search, but now only hundreds instead of millions. They searched them all. This one had no planets. Those two were close binaries where no planets could possibly support life, even if planets had existed. These others were too new and bright, too young to have given life a chance to evolve—And then there was this other one.
It wasn’t prepossessing. It was a cinder, too small and dull to be even a neutron star. True, it was in the right place. True, it did have planets . . . but it had been a nova hundreds of thousands of years before. All its planets were scorched bare. There was nothing left that could be called a living thing.
But on the fourth planet . . . there was a line of rubble across a valley that had once been a dam, a tunnel buried inside the collapsed sides of a mountain-yes, this had been the place the starwisps had come from.
And once again the Heechee had got there too late.
It was almost as though, the Heechee thought, someone had been going around the Galaxy wiping out civilizations before the Heechee could get to them.
Or before those civilizations could get living representatives of themselves into interstellar space.
And then the Heechee made one final, terrifying discovery. They sent out an expedition under a wonderful Heechee female named Tangent, and the whole nightmare picture came together for them.
I won’t tell you about Tangent.
The reason for that is that sooner or later Robin will. He doesn’t know that yet. He doesn’t know that he himself wifi hear it shortly from someone who knew it at first hand. He would know that if he would let me tell him about this person-or, indeed, about some other persons whose presence on Gateway will matter greatly to him. But Robin can be quite obstinate when I try to tell him things he really ought to know.
That is the story; I apologize for the discursions. Let me just add one thing. It is not, exactly, irrelevant.
I implied, a while ago, that although I “knew” that e to the i times pi power equaled—1, I didn’t understand “why.” I mean, there is no intuitive reason why (the base of the natural logarithms) raised to the power of ((the square root of minus one) times (the ratio between the circumference and the diameter of a circle)) should equal anything in particular at all, much less a simple negative integer like minus one.