Hello everyone - was wondering if I could get some feedback/advice for a planet map that I have been working on. If possible could I have some suggestions on whether I need to modify the landforms in order to be plausible expecting a similar amount of continental drift and geological activity as Earth. Its a small almost dwarf planet towards the outer edge of a orange dwarf star roughly 0.85 x the Sun.
Alternate Planets, Suns, Stars, and Solar Systems Thread
- Thread starter Pragmatic Progressive
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I do apologise for the late reply (assuming this is in response to me!) - you certainly can I would be delighted.
It looks great, but I'm afraid the Robinson projection doesn't work like that: the way you've drawn it, the southern continent would narrow to a single point at the south pole.
Yeah, I think you will want to stretch out the alt-Antarctica to go all around the South Pole. Otherwise neat map.
I was thinking on making maps for proposed surfaces of high-ESI exoplanets such as Kepler-438b, when I get the right maps to do it.
Reasonably pleased with the final result for that little exoplanet. Have corrected the suspiciously pointy southern continent and got around to doing some rough calculations for the orbital mechanics and so on for it. I will be doing a worldbuild/scenario thread on the ASB section somewhen soon which will be the "official" version but as previously mentioned I would be delighted and honoured if anyone wants to use it for anything! I have made the primary of the star system a M3.5 Red Dwarf now because of mixing some half-completed projects together.
Radius - 3,374 km
Mass - 0.151 Earth
Density - 5.605
Gravity - 0.54g
Semi-Major Axis 0.405 AU
Eccentricity - 0.13
Ethel 3
Radius - 3,374 km
Mass - 0.151 Earth
Density - 5.605
Gravity - 0.54g
Semi-Major Axis 0.405 AU
Eccentricity - 0.13
So, question for smarter people than me - could a binary planet system (where two planets orbit each other) form between objects of Neptune/Uranus size?
Binary gas giants would much more difficult to form than binary terrestrial planets. This is due to the stability needed in the accretion disk in the pre-planet stage. Also it is a tendency for gas giants to rapidly accumulate mass so I think one proptplanetary body eats up the other in the planet-building process. However, it could be possible, due to perturbed orbits.
I was imagining it forming due to the collision or near collision of two already formed ice giants.
Could anyone knowledgeable about biology tell me whether iron carbonate is hypothetically possible and practical as an alternative to calcium carbonate when it comes to xeno-animal shells? If iron carbonate isn't possible then what is the strongest plausible material.
All I gotta say is that a planet where an animal shell (generally made of refuse OTL) is made of IRON chloride, that planet is gonna have to have an absolutely massive amount of iron for it to work.
Iron Sulfide would work though, since there is a species of snail, the Scaly-foot Snail, that has a shell made of Iron Sulfides and has iron sclerites on its 'foot'.
trurle
Banned
Well, in current continents configurations and without moons the axial tilt is going to be unstable (too much land and ice near poles). Not really a problem for one snapshot, but climatic history of the planet is going to be violent. Also, too many continents. The mantle circulation for the planet of essentially the Mars size is going to be a single-cell (unless planet is very young), producing a single (and likely small) stable continent (Tharsis on Mars) and chaotic lowlands which can be under or over the sea level.
Also, the possible problem: M3.5 dwarf is going to be ~2% of solar luminosity, resulting in planet insolation at 0.4 au similar to Ceres in Solar System. May be too cold to maintain oceans unless you have some exotic sea chemistry (i.e. liquid carbon dioxide or ammonia) To make a habitable planet on such an orbit, you need K7-K9 star.
Also, too few erosion landmarks. Planet of Mars size and with ocean is going to have very impressive fjords, bays at flooded river mouths, and scattered barrier islands at the ends of continental shelf. If absent, this planet is very young.
P.S. Actually, everything is down to planet age. Map more or less plausible for very young (<0.5 Gyr) planet, but utterly strange for earth-age planet of Mars size.
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Thanks for the detailed analysis - will really help with trying to make it more scientifically plausible. Guess that is what happens when you trust Wikipedia for calculating habitable zones! I was aiming it to be just on the edge of being habitable or not for the setting but guess I went a little bit too far.
As a quick additional question if its alright would the fact that it had been terraformed from a relatively uniform icy surface within the last couple of thousands years make much difference to the expected landforms? I wasn't sure whether that would be long enough to form fjords and so on.
trurle
Banned
If on the outer edge of a habitable zone, there still enough precipitation in form of snow to drive glaciers. With nearly 100% humidity due total ice cover, snow will eventually accumulate (albeit slowly) and glaciers will carve fjords everywhere.
So, from what I've researched online, for a moon of a gas giant to be habitable to large earth-like lifeforms, it would be unlikely but not impossible. For the moon to approach Earth in size, it seems more likely to be a captured satellite than a naturally occurring one, or else it orbits a planet much larger than Jupiter. So assuming we get a really big moon of a gas giant in the temporal zone, which is the right size/distance from the start to retain liquid water and not get it's atmosphere roasted by solar radiation or the planet's magnetic field, what would the climate of this moon be like? It would almost certainly be tidally locked with the planet it is orbiting.
Scratch that, apologies. Rather embarrassingly it appears I have misread a logarithmic scale!