Thargleb looked out from his perch at the radiation of the universe surrounding him. He was the last of his kind and he could look back over a long, proud history of prosperous civilization. Not that he could remember it all himself, of course. His personal life had lasted only few hundred Oscillations, a minuscule fragment of the total stretch of time that his culture had lasted, from its original rise from the chaos of unconsciousness over two trillion Oscillations ago.
It had taken 1.2 trillion Oscillations of the Element for lifeforms of his type to auto-organize out of the chaos of radiation around the tiny rock on which they lived and become self-aware. Of course, then their technology took off and very quickly they had learned to control and manipulate radiation generated by exciting atoms of the simplest element, which they also named the commonest element. They had generated such organized radiation for almost the last trillion Oscillations. He had access to the stories and songs, speculations and science of his people in the memory device he kept always with him.
They had wondered, and some had worried, whether the radiation they produced and released would ever be perceived by other consciousnesses on some other world. Would such others be friendly or hostile? On the one digit, since the universe seemed such a forbidding place, dangerous and unforgiving, there seemed little reason to assume that such strangers would be friendly. On the other digit, other consciousnesses confronting the same danger and indifference would surely have similar thoughts and realize that wherever and however it arose, all consciousnesses had to share a kinship and bear each other at least a measure of sympathy.
They had listened carefully through the long Oscillations but no response had ever been detected, or if it was detected, understood. There didn't seem to be any consciousness or culture anywhere else, and soon even this one would be over, ending with Thargleb's life since he was the last. He calmed his mind with reflections on the 55 protons of the Life Element and how they held existence together. Other elements did exist, to be sure, but none were crucial to life and awareness as the Life Element was. He waited for the end, his awareness full of a bittersweet blend of gratitude at the beauty, curiosity, and excitement of living awareness and sorrow at its impending extinction.
Jerry opened the packet containing the latest output from the SETI project at the Big Ear radio observatory and sat down to study it. The signal jumped out at him almost immediately. It was a strong signal in a narrow band near the frequency of hydrogen's characteristic absorption lines in the electromagnetic spectrum. Looking at the intensity characters carefully, he could see how it rose from near zero to a strong signal, then fell off to near zero again.
It had the hallmarks predicted by Cocconi and Morrison for a signal produced by an extraterrestrial intelligence: a narrowband signal close to the frequency of hydrogen much stronger than the background radiation it had to compete with.
He circled the signal and wrote "Wow!" in the margin.
Over the years, the "Wow!" signal became famous and many scientists and observatories hunted for a repetition, not realizing that that one 72 second burst of energy represented the complete electronic output of an entire civilization that had lasted about a trillion oscillations of a cesium atom -- a period of time a human would count as about 100 seconds.
By the time the humans responded, Thargleb and his people had not existed for several times longer than the period of their flourishing.
Morglat took the new data and began examining it. It was from the HADA, the Hunt After Distant Awareness.
Morglat's kind had only recently evolved as interactions among the material bodies near the center of their galaxy. They had begun to understand some of the sorts of radiation through which they floated. They were looking for other awarenesses. The theory was that if there were other awarenesses somewhere, they would produce radiation near the frequency of the most common element and that such structured radiation could be detected.
Morglat and his sibs hoped that such distant awareness would be friendly, naive, and tasty. They were hungry. So they waited and watched.
Each entity survived for several galactic years. Morglat himself had endured for five galactic years now and he was considered an old man. He could still find a pattern, though, and the strong signal reflected in the data made him howl with joy.
Of course, the others wanted to know what he had found. He told them, but when they looked there was nothing there. The human race had produced a few thousand years worth of electronic radiation over the course of their civilization before they had ruined their world and driven themselves into extinction. To Morglat and his ilk, one thousand terrestrial years represented a subjective time period that a human would have called a minute. The humanity signal was over before Morglat could start thinking about what it meant and of course it was never repeated.