Captain's log, stardate— HAH! I always do that. Sorry. Captain's log, 32nd October, CE 2967. Mission Elapsed Time: seven months, fourteen days. Current position: two hundred light years from the nearest human-inhabited planet.
Have altered course to investigate a very faint distress signal coming from a nearby star system. The star is a G-class; distant and unremarkable enough to have no name other than the computer-assigned designation MDEC+56.00938. In accordance with UAAE Object Naming Protocol we have dubbed it Vontus. We are now moving into orbit around Vontus 6c, a terracompatible but dark and cold moon of the system's only gas giant, from which the signal appears to be originating.
*
"We are now in stable orbit around Vontus 6c, captain," announced the pilot of the UAAE Ambidextrous.
"Good," replied the ship's captain. "Maintain orbit. Begin deep all-frequency passive scans of Six and its moons, and launch a probe to give us a look at the far side. What of the distress call?"
"The message appears to be emanating from a half dozen signal buoys in orbit around Six Cee," said the communications officer. "Message is... captain, this is impossible. We're two hundred light years from the nearest colony, but the message is being broadcast in Earth Standard... and the callsign is yours, captain!"
"Put it on the screen," said the captain. A picture flickered up over the main bridge, in the place of what was usually a panoramic star-studded image of the Ambidextrous' surroundings. The man who appeared - between vigorous bursts of static - was bearded, bloodied, sweaty and perhaps a little older, but quite recognisably the captain.
"Thi-- captain J-- --re of the UAAE Ambid--s," it announced. "W-- landed-- -- -- two months ago. Set up-- killing crewmen. Unstoppable. Grasers and railguns-- --effectual. Can't-- --age to UAAE Comm-- -- -- --and here. Repeat. DO NOT L-- --ERE. Temporal flu-- --extreme danger to the rest of-- cannot let -- esca--..."
The message turned to plain static. "That's all there is, captain. The message is dated... sir, it's dated 16th October 2968, almost a whole year from today!"
The captain ruminated. "What have scans of Six Cee found?"
"The moon appears normal, if chilly," replied the ship's computer pleasantly. "There are some strange geothermal readings coming from a position towards its north pole, consistent with the impact of a ship comparable in size with our own some months ago. There is also the expected large magnetic field from the gas giant, Vontus 6, and an above-average background positronic wind which seems to be blowing almost directly away from Six Cee itself."
"Positrons? Electrons moving backwards in time?"
"That's one interpretation, captain."
Further thought. "All right. Recall the probe. Finish our survey of the system and resume our previous course."
"Sir, don't you want to investigate this?" queried the captain's second-in-command.
"Hell no."
*
Captain's log, supplemental. Decided my alternate self probably has extremely good reasons for warning off other ships, and attempting to land or investigate would most likely endanger my ship, my crew and myself as well as perpetuating what appears to be a temporal causal loop. Dropped an additional warning buoy just in case the others fail, and resumed course for the Blue Void, only four hours behind schedule. | 
