[ WP ] In an alternate universe , two earths orbit our sun . Today we finally launch a first mission to visit our sister planet .

You would think they were only 6 months away, no? 
 
 So goes the naive thinking, but orbital mechanics is a bitch and the trip takes 3 years. Halfway out to Jupiter, and then back down. 
 
 It was n't exactly how we expected first contact. Little green men ushering us into the pan-galactic community was the hope. Easy to say that did n't happen. 
 
 And it did n't even assuage those primal questions and fears. Who are we? Who made us? Are we alone? Well, to the third point: no, we're not alone. But not alone in the most uselessly possible. 
 
 Our SETI and their SETI using our Arecibo and their Arecibo ( respectively ) to look and listen. Suddenly a pattern cut through the static: nearly the same message we sent came back. 
 
 At first we thought it was some reflection off of Io or something like that, which would explain the minor differences between outgoing and incoming. But a resonance pattern developed between the messages we sent ( and they sent ) and we received ( and they received ). 
 
 Equally smart and equally sharp scientists on either end found out how to modulate this, control it, and make meaning. 
 
 So we had a conversation going. And we shared a lot. 
 
 The differences in history, language, and culture proved minimal. Sure, externally measurable things were off a phase: Halley's Comet, positions of Mars, etc. 
 
 Some of the'coin-flip' moments of history went the other way. The Stauffenberg plot succeeded, Hamilton won the duel, Remus gets the credit over Romulus. Little things. And our timeline seemed just as weird yet familiar to them. 
 
 This had even spurred on a new historic/philosophical/theological school: that there is an inertia to time, and that somethings must be, but most things do n't matter. Of course the same school developed over there, and for the same reasons. 
 
 We agreed to launch at the same time. 12 people on each ship. Six each were people we thought we had exact counterparts for. The other six were as random assignment as the project allowed, to test how chance worked through across this gap. 
 
 The two crews were forbidden to directly contact eachother, but both Earths talked to both ships. As our crew neared their planet, we got ready to receive the sister ship. 
 
 You never expect the figure in the mirror to step out into your room. But today he did. 
 
 One wife upon meeting her mirror-husband experienced a psychotic break. 
 
 One parent meeting his mirror child could n't tell any difference, and just continued on like normal. 
 
 One brother killed his mirror immediately. On the other side the murder still took place, but with the roles reversed. 
 
 No one had anything to learn, or any new ideas to present. We both had the technology for trip through space, we were both stuck at the same point in unifying quantum physics with general relativity, we both were starting to master genetics. 
 
 With the interaction proving both dangerous and fruitless, neither public was much interested in continued exchange. 
 
 We each sent our ship back, and from each a couple people decided to stay in the mirror world. 
 
 We kept in contact, but limited it to simpler matters. Science, asteroid tracking, search for *other* life in the universe, that sort of thing. 
 
 So we're not alone. But it does n't matter. 
 
 When you look up in the night sky, you're looking away. And when you lookup in the day, the sun is in the way. 
 
 The orbital dance of symmetry continues unaffected, disinterested.
