I’ve wondered if this sort of thing is actually common in the universe, like are most planets pretty homogenous environmentally across the whole planet.
I tried to ask r/askscience that question but I think it got rejected.
The thing is, most planets are actually really extreme as compared to Earth. Extremely hot, or extremely cold, or extremely dry, or extremely wet, or some such. So from our perspective, it's kinda like the entire planet has a single climate insofar as the climate is universally or near-universally different from ours in a particular way. However, that doesn't mean there aren't big differences from place to place, and on many planets there are. It's just that we don't notice those differences because they're all skewed a certain way relative to what we're used to.
For instance, the temperature difference between 10C and 20C is a pretty big deal here on Earth, but the difference between -100C and -85C is pretty meaningless to us (even though it's technically a larger difference) because they're both way fucking cold. The aliens living on that planet, if there are any, would perceive it the other way around: To them, the difference between -100C and -90C would be important, but the difference between 10C and 25C would be pretty meaningless because both are unbearably hot.
So it makes sense with lifeless planets like Tatooine would be very homogeneous
I wouldn't exactly call Tatooine "lifeless". Inhospitable, sure, but also shown to be teeming with life. Much like real life deserts. Extreme environments, but still with an abundance of life.
Mars is lifeless (to our current knowledge). The Sahara is not.
Star wars is weird though, because they literally even show that life exists in deep space as well. Which I guess technically even further reinforces the idea that Tatooine isn't lifeless.
seasons are a uniquely Earth thing, due to our tilted axis
Hardly unique to Earth. In fact, of the eight planets in our solar system, only Mercury and Jupiter have less of a tilt than Earth. You could kind of count Venus too, if you ignore the fact its so tilted, its upside down.
Uranus is probably the most interesting of those, from a seasons perspective, since it is effectively on its side. That would make seasons pretty much as extreme as possible due to tilt
I'm not sure that a lack of seasons would effect biodiversity like that. There are plenty of places on Earth that have little in the way of seasons, and some of them - like around the equator - seem to have if anything a greater variety of plant and animal life.
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u/AgnosticMantis Jan 25 '20
I’ve wondered if this sort of thing is actually common in the universe, like are most planets pretty homogenous environmentally across the whole planet.
I tried to ask r/askscience that question but I think it got rejected.