Years ago, someone made a documentary – “A Private Universe” – in which they talked to to a gaggle of Harvard students at commencement & asked them what caused the seasons. Almost all said that summer happened when we were close to the Sun in our elliptical orbit, winter when we were farther away. Which isn’t true – not of Earth, anyhow.
Now you might think they were just jackasses, but they make up a key fraction of our intellectual/governing elite. It can’t be that simple – they can’t just be a bunch of ignorami – there has to be a deeper, more subtle explanation.
When you think about it, it’s obvious that these beings came from another planet in some other solar system. Earth has an axial tilt of about 23.4 degrees and an orbital eccentricity of 0.0167 (close to a perfect circle) but other planets could differ and have seasons largely caused by orbital eccentricity. Seasons would be some different – summer would hit at the same time in both the northern and southern hemispheres.
It’s perfectly possible for a planet to have high orbital eccentricity: most known extrasolar planets do, usually something like 0.25 , although most of those are giants that probably wouldn’t suitable for life. Low axial tilt is also possible: for example, Venus has an axial tilt a little under 3 degrees, while Mercury has almost no axial tilt. We don’t yet have measurements of the obliquity of exoplanets, but tidal theory suggests that it tends to become quite small over time for planets in the (close-in) habitable zone of low-mass stars – possibly the most common kind of habitable planet.
The Cantab planet has to have an eccentric orbit, but mildly so: 0.10? The natives don’t seem shocked by the intensity of Earth’s seasons, just confused about the pattern and cause.
What else can we deduce from the characteristics of its natives?
Likely a higher fraction of its surface is ocean than is the case for Earth. Harvard graduates have a lot of trouble accepting or understanding the idea that human populations, having been separated and exposed to different evolutionary pressures for tens of thousands of years (even longer in the case of African hunter-gatherers), have evolved in different directions. Suppose that intelligent life on Cantab originated on an island continent, such that every other significant piece of land was several thousand miles away. Something like Hawaii, but larger. Unlike humans, who expanded to most of the world well before behavioral modernity (homo erectus) and almost all of the world before the invention of writing, Cantabrians must have originated on a small continent without significant internal geographical barriers (nothing like the Sahara Desert) and then only expanded to the rest of the world after developing fairly high-class sailing ships. So in Cantab, the expansion of the local intelligent race was more like the post-Columbian European expansion – recent. People on Cantab – they’re something like people – are no more different from each other than Aussies and Kiwis, and they find the idea of more significant differences, the kind we see on Earth, alarming and hard to digest.
Cantabrians also seem to have trouble with admitting the existence of differences between the sexes. I suggest that back on Cantab, the natives may have been fairly androgynous, rather like gooney birds. Here their sex differences are much larger, nearly as large as in real humans. Perhaps something in Earth environment has triggered an exaggeration of their originally small intersexual differences. Perhaps they used something like vitamin D as a trigger for sexual development. But less of that compound was generated back in a world with a red sun, and low levels of ultraviolet. Here, under a yellow sun, sex is super-powered.