They told me that as the first Exchanger, I should have at least a basic understanding of all aspects of the mission. And sure, I could regurgitate technical jargon well enough to pass the NASA tests. But the true technicalities of Quantum Warp Travel was well beyond the grasp of most physicists, and so even asking me, a diplomat in essence, to be able to explain the basics of matter is a legitimate stretch. Something to do with twinned particles linked through higher dimensions. It turns out the old Germanic myths were right on one thing - we all have doppelgangers. And they're on the other side of the universe.
My doppelganger was supposedly very much like me. From the few cryptic messages we received from the other side, it was evident that they were much like us in almost every way. Who would have thought that a place so far away would be so similar to our own home? They were humanoid, and could understand our logic. People were quick to propose that theirs was a mirror world - identical to our own but opposite in something like particle charge or spin. But it was not so. Their world bore many reflections of ours, but if it was a mirror that our messages flitted back and fourth through, it was a severely warped or splintered one.
For years, the technology involved grew exponentially on both sides. At first our translations were clunky. "We eat. We breathe. We think. We sleep." Some messages we assumed were not compatible with our language or culture: "We swim you. We through you." These communications grew in complexity and volume as the years passed but with similar blocks in full understanding.
We realized each person here could somehow be mapped to correspond with someone on the other side. Our subparticles, or the motions they cycled to, were unmistakably linked in some way to individuals on their side.
And that is how I was matched with the one who must have destroyed my world. As I float here in an orbit meant to taxi along my home planet, and face empty vacuum instead, I regret it all. The eagerness of our species to make the exchange - to connect with outside intelligence. My acceptance of the mission due to my body's unique reaction to radiation.
The exchange lasted a moment. I was in their world, the zapped back to mine. There was nothing here when I came back.