The two astronomers were stealthily stalking a small group of wildebeest on the African Savanna while taking a break from their research. One of the magnificent but twitchy bulls seemed on edge and sensed that something was amiss. Perhaps it had caught a whiff of the perspiration from the two astronomers. The wildebeest began a quick trot that the astronomers had to keep up with if they wished to capture a few photos of the encounter for their office wall decorations. But the change of scenery from the cramped cubicles back at the lab to the grand vistas of the savanna was a welcomed break even though they had little to show for it. After 15 minutes they abandoned the chase and returned to camp to discuss their research.
They talked about the bizarre exoplanet their survey had turned up. It was the talk of the scientific community, and speculations had run rampant about what it all might mean.
After cataloging 150,000 planets with the new satellite observatory their research team had found an Earth-sized world with liquid water oceans and an oxygen-nitrogen atmosphere. It was clearly hospitable for life and had a thriving biosphere, but something was wrong with the analysis. Its only detectable moon was impossibly bright, and reflected light at 99 percent efficiency. Not even a fresh polar ice cap could muster more than 85 percent. It was as though a large portion of the moon's surface were covered by some kind of reflecting mirror. Detailed analysis of the moon's orbit, phasing and eclipses with its planet had shown that the mirror was probably well over 100 km across. It was the only exoplanet in the growing catalog to show signs of actual alien technology. Plans were soon set in motion to send an unmanned probe to this planetary system 45 light years from the sun to see what was there. At the fastest achievable speeds, it would take 130 years for the probe to arrive, and 45 more for scientists back on Earth to receive the data by radio transmission. It would be the lucky next generation of scientists to finally uncover the mystery of this enigmatic system.
The Aliens had been busily cataloging planets for over a century once the instrument on their largest moon had been completed at great cost. The Aliens had spent millennia establishing a global society that was well-fed, stable, and satisfying to its 10 billion members. Now it was time to turn outward to the stars to reveal greater vistas to contemplate. Over one million worlds and 300 similar to their own had been discovered since the Great Telescope began operation. An armada of probes would now be sent to these 300 worlds to see if more than bacteria prospered in their biospheres. The probes would be the marvel of von Neumann, nanotechnology engineering so that the highest speeds could be achieved at the lowest cost. One of these probes was selected to make the journey to the nearest of these worlds only 45 light years away. It would arrive in 55 years and with any luck the scientists alive today would learn the results in their Old Age 100 years from now.
The Earth probe arrived and immediately went into orbit around the enigmatic planet. Its blue skies, white clouds and abundant oceans made it a twin to Earth though with unfamiliar continents. The probe darted past the moon, and with its imaging systems fully activated, had revealed the bright surface region to be a vast optical telescope consisting of thousands of segments; each a perfect mirror, although slightly dimmed by a thin layer of accumulated cosmic dust. The probe's imagers hungrily explored the volcanically active planet from its polar orbit, taking thousands of high resolution photos and transmitting them back to Earth to arrive 45 years later.
The land areas of the alien world were heavily forested, but patches could clearly be seen with buildings and roadways of unfamiliar design and purpose. On one continent, a large portion of a vast city had been engulfed by the solidified tongue of lava from a nearby volcano. Yet the probe's radio sensors detected not a single watt of radio energy, and the nighttime view of the planet revealed no luminescent carpet of artificial lighting. What had finally happened to force the Aliens to abandon their home world? Where did they go? It was not the probe's purpose to frame questions, and so 45 years later scientists spent the next decades trying to understand what had happened to these creatures.
The alien probe passed through the solar system with its sensors active and sent back to its handlers images of Saturn's gossamer rings. Taking up an orbit around Earth, it stealthily took millions of images of the planet's surface.
What a lovely world, and much like the Alien's own! It had far fewer continents though most were considerably larger than those on Homeworld. As the probe's powerful imager scanned a vast flat region on one of the continents it saw many moving creatures that were low and squat with four legs. On the next pass 90 minutes later, the creatures had traveled considerably as though in flight. Into the mix, there were now two bipedal creatures apparently in pursuit of the heard. Some kind of predator-prey tableau was playing out for the alien instruments in real-time. The imagers were so powerful, details on the creatures could be seen quite plainly so that life forms on this world could be properly catalogued.
As the alien probe passed overhead on its path across the verdant African Savanna, the two velociraptors stopped in their tracks to note the curious high-speed star as it streaked towards the distant horizon.