When Mission of
Gravity was finished in late 1952, I had a perfectly honest
degree in astronomy. I nevertheless made a few mistakes, including
one in basic physics; I said, somewhere in the story, that the
Bree would sail faster with the wind behind
her. Predictably, a sailor caught that one.
More seriously, I erroneously took for
granted that the figure of rotation which was Mesklin would be an
oblate spheroid, and did all the gravity calculation (on a slide
rule) assuming that most of its mass was degenerate matter very
close to the center. John Campbell told me when he accepted the
story that a mathematician had told him that Euler must be spinning
in his grave, but I still don’t know what theorem I
violated.
More usefully, a few years after the
story was published, members of the M.I.T. Science Fiction Society
(MITSFS) managed to get enough computer time to figure out more
nearly what the planet’s shape would be. They were presumably
right; all I could console myself with was the realization that I
had written the story to give pleasure to people even if that
wasn’t quite the specific pleasure I’d had in mind.
I eventually did get a computer, wrote
a relevant program in BASIC6, and came up
with an object looking more like the discus used in field and track
sports—an object fairly sharply curved at the poles, much flatter
in the midlatitudes, and coming almost to a real edge at the
equator. With arbitrarily chosen three g’s at the equator, the
polar gravity came out to only about 275, as I recall.
I assume that readers with appropriate
background knowledge and computer hardware will want to check this.
Maybe someone will want to write a
book on the things that minor differences in the basic assumptions
will do to Mesklin’s shape.
Personally, I wound up doing forty
years of high school teaching instead of being an astronomer
essentially because of my mathematical weaknesses.