I entered the damp steel chamber of the airlock, relieved to be out of the thick planetary atmosphere. Despite my status as a post-graduate researcher I was not exempt from patrols around the research station. I placed my heavy crossbow in its rack: with difficulties in resupply we had to hoard our small stocks of ammunition; besides, the cunningly-designed arrows were buoyed up by the dense air, and flew further.
I was here to research the huge, enigmatic time flies; alien insect-like creatures which moved through space and time in a manner tantalisingly different than ourselves. The time flies were differently shaped: some looked like bigger versions of the arrows we fired from our crossbows; others were more bulbous. In any event they were strange and threatening; we had had to kill more than one.
My supervisor, Professor Clare Youell, greeted me as I entered her time lab. My current project was tracking time fly trajectories but I was puzzled as to how best to go about it and where I might get the equipment. This was my chance to seek guidance and I seized the moment.
“Oh,” she said, pointing airily to the arrow ballistics department the other side of the corridor, “the best way is how the crossbow arrow research guys do it."
“You should time flies like an arrow," she continued, “You’ll find they have all the necessary equipment across there.”
I made a note to find out how the various designs of arrow were timed as they were fired from test crossbows. No doubt the approach could be adapted for my own research.
I was struck by a new picture hanging behind Professor Youell’s desk. It depicted the results of a patrol the previous week which had encountered a hostile time fly. The patrol had made short work of it and the picture showed the fly pinned to a native tree by a well-aimed arrow.
“Time flies like an arrow!” the Professor observed sardonically.
I summarised my latest thinking.
” In the almost-flat space-time around this planet, light cones aren't really tipped at all."
"To a first approximation here, time flies like an arrow," I added, "but the time flies seem to weave their own strange geodesics around it. It’s quite remarkable.”
I paused for a moment.
"The thing is, I don't know which sort of time fly to measure first - the spherical ones or the ones which look like arrows?"
The Professor looked at me strangely: “So you still haven’t found the fourth parsing then?”
I had no idea what she was talking about.