The Earth looked like a cannonball to Captain Anderson as he eyed it from the vantage-point of his spacecraft, several thousand miles into space.  He had heard the usual clichés about footballs and baseballs, but to him the analogy with a cannonball, despite its anachronistic nature, appeared more appropriate.  He cast a glance over his right shoulder at Major Jim Green, who at that moment was staring down at the central control panel, and said: "You know, every time I take a good look through that porthole, I get kinda mystical about things down there, including the Earth.  It seems odd that most people should be leading fairly humdrum lives on that planet of ours."

      Major Green gently nodded and then briefly glanced through the same porthole, behind which the Earth lay static and diminutive, no bigger than an average football.  "The oddest thing for me is that people should be living there at all!" he exclaimed on a softly humorous note.

      Colonel Timothy Boyd, the third astronaut on board Craft AV6, volunteered the opinion that nothing was odder than space flight, especially with two nuts aboard.  "You'll be saying that Earth looks like a goddamm cannonball next!" he snapped at Anderson, and the surprised captain surprisingly retorted that a cannonball was precisely what it did look like to him.

      "You've seized on that analogy more from the planet's size at this distance than from its overall appearance," Major Green conjectured.

      "Could be," admitted Captain Anderson, who fell to speculating again.  To think that people should be standing on their feet on opposite sides of the Earth, never doubting they were the right way up!  Given the planet's circularity, you'd think those underneath would fall into space, did you not also know that the Earth rotated so rapidly on its axis ... as to preclude anyone's being upside down long enough for that to happen.  Then he heard Colonel Boyd saying, as though to himself: "It ain't usually the mystical types who get sent up here, but more goddamm down-to-earth guys!"

      "That's right," Major Green seconded.  "Guys who want a spiritual trip through space can't be trusted to take the material one.  My guess is that the material trip is a prelude to the spiritual one, seeing as the latter can't be made just yet."

      Colonel Boyd guffawed dismissively, but Captain Anderson protested that his mystical feelings were fundamentally of a materialist order and simply pertained to the so-called heavenly bodies, which seemed to function like clockwork.  "After all, the Earth is basically in the position of an electron circling the proton nucleus at the heart of the Solar System," he went on, "and the resulting pattern conforms to an atomic integrity.  You can't expect the planets to break loose from their solar moorings, so to speak, and soar towards the heavenly Beyond, like pure spirit.  They're stuck with their proton control for as long as it exists."

      "Unlike ourselves, whose spacecraft is free to voyage in any given direction as far as its fuel tanks will allow, before it begins to drift," Colonel Boyd postulated.

      "And yet, you can't voyage to the Infinite in a spacecraft," Major Green objected, showing no fear of his superior officer.  "The spiritual journey and the material one are entirely different.  Besides, space is finite, so you'd be bound to return to your starting-point eventually."

      "I've always found that difficult to believe, since space is spatial and can't have a beginning or an end," Captain Anderson demurred.  "Only the mind is finite, whereas space goes on and on forever, as you can see."

      Colonel Boyd winced in response to the apparent lack of Einsteinian perspective in his junior officer.  In all probability space was infinite, but in an age when man's mind was expanding towards the Infinite, it didn't do to regard space in a similar light.  "What you've always overlooked," the Colonel said, "is the fact that space is curved.  For once you've grasped that fact, you'll understand why a body will return to its original starting-point if it persists long enough in a uniform direction."

      Major Green nodded his confirmation.  "A serious lapse of scientific subjectivity in relation to the higher subjectivity of the superconscious mind!" he solemnly averred for the benefit of his junior colleague.  "You shouldn't allow yourself to be influenced by those anachronistic quasi-Newtonian notions that were officially discountenanced some decades ago.  You'll be telling us, before long, that not curved space but goddammed force and mass keep the planets in rotation around the Sun!"

      Captain Anderson demurred with, for the environment, a quite vigorous rejection of that assumption.  "I shall do absolutely no such thing!" he assured the major.  "A post-atomic age demands a post-atomic world view.  A Newtonian/Einsteinian compromise would simply be out of the question."

      "Glad to hear you say so," Colonel Boyd remarked in a conciliatory tone-of-voice.  "We don't want to look at the planets too objectively these days.... By the way, did you ever read Locklin's account of antithetical equivalents?"

      "Unfortunately not," Captain Anderson replied, with a slightly guilty look on his face.

      "Well, I did," Major Green admitted, smiling.

      "Really?" the colonel responded.  "Well, there were one or two antithetical equivalents that Locklin didn't think of," he proudly informed them, "and you'll never guess what."  He paused to allow his second-in-command to ponder the matter a moment but, since Major Green made no comment, continued by saying: "The first one concerns the antithesis between moons and satellites, that is, between natural satellites and artificial, or man-made, ones - the latter functioning on an entirely different plane, superior in every respect, to the former.  And the second one, believe it or not, concerns the antithesis between shooting stars and spacecraft or, as they used to be called, rockets.  This second antithesis directly concerns us; for whereas shooting stars shoot naturally through space, with their solar propulsion and flying tail, we, their antithetical equivalents, shoot through it artificially, driven-on by the engines of our craft, which leave a comet-like streak in their goddammed wake.  Should either of you spot a shooting star today, you'll be looking at our near-absolute antithesis, which could be defined as a natural rocket."

      "Remarkable!" Major Green exclaimed.  "You must write about that when we get back to base."

      "And thereby expand our knowledge of antithetical equivalents," Captain Anderson added half-jokingly.  "Say, Locklin didn't write anything about British astronauts, did he?"

      Colonel Boyd guffawed and resolutely shook his head.  "The day the goddamm Brits get into space will be the day I quit!" he cried, and, for once, both of his colleagues were inclined to believe him.