I have a copy of A Popular Handbook and Atlas of Astronomy (by W. Peck F.R.S.E., F.R.A.S.)* that, according to an inscription, was given to my grandmother for Xmas 1896 by her Aunt Emily†. It gives us striking assurances about Venus and Mars.
By the same analogy, one might suppose that Mercury is an analog of the primordial molten-surfaced Earth. Or that the asteroids represent the ultimate fate of all terrestrial planets, breaking up into a million fragments in the manner of Krypton, and perhaps leaving relics of their destroyed civilizations to be found (as I believe Heinlein showed in Space Cadet).
In this astronomy we don’t have to account for the Kuiper belt, so everything beyond the asteroids is gas giants with more or fewer moons. One might regard them as nascent solar systems of their own (and that would certainly fit the Victorian progress-of-life model), though whether they could be seen as the successors to ruptured planets is less clear. More probably, I think, a planet ruptures as the result of moral failure, or goes on to become a paterfamilias.
In that era, of course, no one knew about Pluto, though later Lowell was involved in its discovery, I believe.
One source I read classified Jupiter, Saturn, Uranus, and Neptune as a different category of celestial bodies.There were bodies of radius comparable to Earth’s, the terrstrial planets; bodies of radius around 100x that, such as the sun; and intermediate bodies of radius around 10x Earth’s, such as Jupiter. I think they regarded the intermediate bodies as hotter than Earth, but not as hot as the sun, which would hinder their moons having life-supporting climates, I think.
I think I would not. Pluto was classified as a planet from its discovery through classic science fiction (Smith, Heinlein, and Niven all call it a planet) up to, I believe, the end of the millennium, long after swampy Venus and ancient, dying Mars were obsolete.
Space: 1889 which is available from DriveThruRPG. It’s a Victorian-era space-faring RPG and there are source books that cover the inner planets, including Mars in some detail. Interestingly Mercury is described as:
…a tidally locked world, with one side always facing the Sun, the other the void of outer space. Between the cold of the dark side and the heat of the light side, there is a narrow 100-mile wide temperate zone that circles the globe. All around the zone runs the World River, linking the various lakes and small seas, its flow driven by Coriolus effects.
Giving it a somewhat Riverworld feeling.
Less well known is Marcus Rowland’s Forgotten Futures RPG and specifically the source book Planets of Peril. This has a cosmology based on Stanley G. Weinbaum’s 1930s science fiction stories so in some ways it’s more advanced than Space 1889. Again there’s lots about Mars but this time Mercury is described as ‘not worth visiting’! A footnote about Mercury’s ‘wobble’ kills off the world river:
Mercury’s orbit is very eccentric, and its rotation sometimes lags behind its orbital position, and is sometimes ahead of it. As a result of this eccentricity there is no permanent twilight zone, as on Venus; all parts of the border between the bright and dark sides experience extremes of warmth and cold at some point in the planet’s short year.
But even that's not right!
Interestingly I discovered from Wikipedia that the idea of a twilight zone was disproven in 1965 when
radio astronomers discovered that Mercury rotates three times for every two revolutions, exposing all of its surface to the Sun
And that you can thus divide stories about mercury between ones with the twilight zone and ones that don’t.
The Wikipedia article also includes this 1978 quote from Carl Sagan-
A clement twilight zone on a synchronously rotating Mercury, a swamp‐and‐jungle Venus, and a canal‐infested Mars, while all classic science‐fiction devices, are all, in fact, based upon earlier misapprehensions by planetary scientists.
However on the positive side Pluto exists and is the lair of pirates!
Another good thing about Forgotten Futures is that it’s all available on the Authors website for free. However he does ask for donations to support the site and also 10% goes to the charity Cancer Research UK.
I’ve always fancied running something set in this world but up to this point I know absolutely no one who has even the remotest interest in this sort of setting.
Years before writing GURPS Steampunk (which has its own guide to the Victorian solar system), I ran a campaign of Space 1889. I really liked the setting, but my players hated the game mechanics. I was actually using a modified rules set that I created to support a Victorian “Legion of Super Heroes” concept, with characters such as Superbman, Daedalus, and Dame Abigail Penelope De Leon (“Noms de guerre? How quaint!”). I also played with the history a little, with a Greek Empire established after Lord Byron became the king of Greece . . .
I’m familiar with Marcus Rowland’s work (I follow him on livejournal) and I’ve thought of using Forgotten Futures, but my plan was a police procedural campaign set in the London of Kipling’s airship utopian future history. It was another one that my players didn’t quite go for, though a couple of them really, really liked it—just not a critical mass.
Lowell devoted the last years of his life to the search for Planet X and Clyde Tombaugh was hired by the Lowell Observatory in 1929, fourteen years after Lowell’s death, to continue that search. So Tombaugh would likely not have made the discovery of Pluto without Lowell. However the twist in the tale is that it was later discovered that the observatory had taken pictures of Pluto in March and April 1915, while Lowell was still alive, but had mistakenly classified Pluto as a star.
(This has give me a great idea for a Call of Cthulhu scenario where a zombie astronomer is forced to discover the exact location of an undiscovered Great Old One in Space)
Checking the Web page for Garrett Serviss’s Other Worlds (published 1906), I find the following:
Now, the history of the solar system, according to the nebular hypothesis, is a history of cooling and condensation. The sun, a thousand times larger than Jupiter, has not yet sufficiently cooled and contracted to become incrusted, except with a shell of incandescent metallic clouds; Jupiter, a thousand times smaller than the sun, has cooled and contracted until it is but slightly, if at all, incandescent at its surface, while its thickening shell, although still composed of vapor and smoke, and still probably hot, has grown so dense that it entirely cuts off the luminous radiation from within; the earth, to carry the comparison one step further, being more than a thousand times smaller than Jupiter, has progressed so far in the process of cooling that its original shell of vapor has given place to one of solid rock.
Serviss discusses the probability of life on Jupiter’s satellites, and the likelihood that it will once day cool and contract into a solid globe vastly larger than the Earth. Now that would be something to explore!