Alternate Planets, Suns, Stars, and Solar Systems Thread
- Thread starter Pragmatic Progressive
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Yeah, sorry for that. Both would of course improve their planet's fate of being habitable, and I feel that for both planets if would be enough to tip them over the edge into having native life with some sort of panspermia.
History would be comparable to today, other than different associations for color in love and war. Early astronomy and space flight will find that they’re habitable, of course. But I don’t see anyone actually caring about space any more than today. Shame, I know, but look at how pathetic we are right now.
@hurax @BrobDingnag
Let's assume that Mars formed as the mass of the Earth, and that it had kept a thicker atmosphere. Due to it's larger size, it would be able to hold onto a magnetosphere. Let's also say that Phobos and Deimos are both Ceres mass, with Phobos being half the distance of the moon, and Deimos orbiting Mars slightly further out. Along with that, I'll add that Mars's orbit is nearly circular like the Earth's, with it's orbital distance at the closest point it approaches in our timeline. How would this change Mars's appearance, and humanity's perception of it?
Let's assume that Mars formed as the mass of the Earth, and that it had kept a thicker atmosphere. Due to it's larger size, it would be able to hold onto a magnetosphere. Let's also say that Phobos and Deimos are both Ceres mass, with Phobos being half the distance of the moon, and Deimos orbiting Mars slightly further out. Along with that, I'll add that Mars's orbit is nearly circular like the Earth's, with it's orbital distance at the closest point it approaches in our timeline. How would this change Mars's appearance, and humanity's perception of it?
Mars wouldn't be red so it would have less of an association to war, so there's likely a different name for it after another god. You could estimate its brightness to Jupiter, but that wouldn't change so much for the religions down on Earth. Ceres size moons at a closer orbit make far more of a difference, they would have been detected and known before civilizations. The rhythm of their months would be not just a curiosity but something of mystical significance, and the evidence that they are orbiting a planet should be enough that geocentrism gets rejected in early astronomy.
Ah, but is that putting the chicken before the horse? Or are we putting the cart before the egg? Did the color red get associated with war first (simply because of blood), or did red get ascribed to war because Mars was the god of war and happened to be red? Red isn’t the universally accepted cultural color for war, after all. If Mars appeared to flash between blue and green (alongside Venus, by the way, which wouldn’t be a static pale yellow), and if red is otherwise associated with war, would Mars even be called Mars since it isn’t red?
I wish I was booted into Windows right now so that I could open Space Engine and answer this for myself, but… If they’re Ceres mass (I assume you mean size and albedo, too), how readily visible would they be? You can see the Galileans with even simple binoculars. Would two Ceres-size moons at Mars’s closest approach potentially appear as tiny bulges to the naked eye, or would you still need some optics to make them out? Interesting idea.
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@hurax @BrobDingnag
As for the two Ceres-size moons, I don't really know. My intention was for them to not be visible from the Earth, I am not so sure if they would or wouldn't be.
I am thinking that Mars is not a habitable planet (at least for humans), and I would think it would not be blue and green though, due to not having Earth-like conditions. I am imagining an appearance more like this, perhaps? Either one of the two. The intention of the scenario is to not have another Earth-like planet in the solar system, but it being at least be marginally more interesting for humans. I am also curious about what characteristics the planet would have, of 1 Earth mass to 1.25 Earth masses, what coloration, and atmosphere it would likely have.
I am thinking Mars can look like on the left, and Venus is similar to the right. I imagine Venus as a desert-like planet, with a thinner atmosphere. Perhaps it has a thin-Mars like atmosphere in this timeline.
As for the two Ceres-size moons, I don't really know. My intention was for them to not be visible from the Earth, I am not so sure if they would or wouldn't be.
I am thinking that Mars is not a habitable planet (at least for humans), and I would think it would not be blue and green though, due to not having Earth-like conditions. I am imagining an appearance more like this, perhaps? Either one of the two. The intention of the scenario is to not have another Earth-like planet in the solar system, but it being at least be marginally more interesting for humans. I am also curious about what characteristics the planet would have, of 1 Earth mass to 1.25 Earth masses, what coloration, and atmosphere it would likely have.
I am thinking Mars can look like on the left, and Venus is similar to the right. I imagine Venus as a desert-like planet, with a thinner atmosphere. Perhaps it has a thin-Mars like atmosphere in this timeline.
I can't tell since I haven't delved deep enough into the divine associations, just extrapolating from my own cultural baggage of Ares and Mars. Apparently the association with a god of war was first with Nergal and the color motive came later. In Egypt it was Horus, associating both the color and the retrograde motion, the bird turning its head around. Blue Mars could then be any god or goddess and have any name from it. It would also depend how far you would take the parallelism for the real world polytheist relations.
If the moons are visible then you likely would get some father god or mother goddess association, so in Greek maybe it would become Zeus? Or better, have it associated with Hera and later Juno, you get nice names for the planet, keep old Jupiter since we don't change its properties, get good avenues for symbolism.
For the moons to be visible with the naked eye, I just extrapolated from Ceres now, which is visible in good conditions, but it was only found after people were searching for it. If it is next to a prominent planet there will be more attention to it so people can find them earlier. But if you don't want them to be discovered earlier, why change them at all? You would just have the discovery of the Galilean moons swapped for some other moons. There's the thing with moons stabilizing life on the planet though, should that be the focus?@hurax @BrobDingnag
As for the two Ceres-size moons, I don't really know. My intention was for them to not be visible from the Earth, I am not so sure if they would or wouldn't be.
I am thinking that Mars is not a habitable planet (at least for humans), and I would think it would not be blue and green though, due to not having Earth-like conditions. I am imagining an appearance more like this, perhaps? Either one of the two. The intention of the scenario is to not have another Earth-like planet in the solar system, but it being at least be marginally more interesting for humans. I am also curious about what characteristics the planet would have, of 1 Earth mass to 1.25 Earth masses, what coloration, and atmosphere it would likely have.
I am thinking Mars can look like on the left, and Venus is similar to the right. I imagine Venus as a desert-like planet, with a thinner atmosphere. Perhaps it has a thin-Mars like atmosphere in this timeline.
Blue Mars looks nice, but Snowball Earth didn't have complex life yet. But give evolution its time and we will have something, from the looks of it only in the ocean though.
Red Venus though, I don't like that much. On Earth we will have a pretty red Morning Star just dimmer, but it doesn't look amenable for life without water.
Wouldn't two Ceres sized moons next to a planet brighten it up when viewed from far away? Like how Pluto was thought to be a large, singular body until it occulted a star and a 'clear' view of its binary Charon was recorded, or like how half of all the stars in the sky are actually binaries but they appear as single light points because our eyes are physically limited to seeing them as such. Unless the moons were significantly dark bodies from tholin coverage or something idk about causing the same darkness.
Thought I made some calculations first before continuing to speculate... glad I did since it was very far off. Orbiting Mars at half of Lunas orbit gives you a visual size of 12 arcminutes at the closest approach, that's one third of the Moon's visible size. No way you could confuse the system for a variable. As for it being visible, haven't found the formula for magnitude yet but for being at half of Ceres' distance the moons should be visible to the naked eye in good conditions, if only to make it more interesting. So they are probaly faintly visible like Uranus, but get noticed way earlier with their proximity to mars and the short orbital period.
@Pax_Nihil @hurax
If Mars here is not red, then it is likely that it would have had a different name. I don't really know what it would be named. I did some further research on planetary types and I found two that might be reasonable for this situation.
Venus could be a sulfur planet, perhaps? Perhaps it might still have gotten the name Venus because of it's bright yellow color, but only up until Modern telescopes and technology is invented is it discovered to have lakes and oceans of sulfuric acid?
planetstar.fandom.com
As for Mars, perhaps it could have gotten the name Mars still if it was an Ammonia planet? Brown is somewhat-ish close to red/orange? Although, I am not sure if the temperatures of Mars and Venus in this situation would allow them to be Ammonia, and Sulfur planets like these links show.
planetstar.fandom.com
I imagine that from what you are saying about the Moons of Mars here, regardless of whether Mars is an Ammonia planet or not (or a frozen Iceball like the image up there shows), it's Moons would have been discovered sooner. Likely that would have thrown the geocentric theory out of the water much sooner as well but I don't really think that would change borders, politics ,or overall history?
If Mars here is not red, then it is likely that it would have had a different name. I don't really know what it would be named. I did some further research on planetary types and I found two that might be reasonable for this situation.
Venus could be a sulfur planet, perhaps? Perhaps it might still have gotten the name Venus because of it's bright yellow color, but only up until Modern telescopes and technology is invented is it discovered to have lakes and oceans of sulfuric acid?
Sulfur planet
Sulfur planet is a theoretical class of planet with surface covered in lakes or oceans of sulfuric acid with sulfuric acid clouds in the atmosphere. Kepler-52c (Iamidae), Kepler-47b (Mellona), Tau Ceti e (Aita), and KIC 5522786 b (Sreng) are speculated sulfur planets as of 2014. Venus has...
planetstar.fandom.com
As for Mars, perhaps it could have gotten the name Mars still if it was an Ammonia planet? Brown is somewhat-ish close to red/orange? Although, I am not sure if the temperatures of Mars and Venus in this situation would allow them to be Ammonia, and Sulfur planets like these links show.
Ammonia planet
Ammonia planet is an assumed class of planet with surface covered in lakes or oceans of ammonia with ammonia clouds in the atmosphere. Viewed from space, ammonia oceans would usually appear dark brown due to large amounts of alkaline earth metals dissolved in it. Although ammonia oceans would...
planetstar.fandom.com
I imagine that from what you are saying about the Moons of Mars here, regardless of whether Mars is an Ammonia planet or not (or a frozen Iceball like the image up there shows), it's Moons would have been discovered sooner. Likely that would have thrown the geocentric theory out of the water much sooner as well but I don't really think that would change borders, politics ,or overall history?
Some details for my own alternate Venus - somewhat inspired by @DUWANG 's take on it a few months ago.
At a mass of 0.951 Earths, a full day on Venus lasts approximately 19.2 hours, providing a shorter day length than either Earth or Mars. The planet's axial tilt measures at 21 degrees, resulting in seasons throughout it's orbit. The atmospheric pressure on Venus is around 24.2% of that found on Earth. While lacking Earth's mobile plate tectonics, this planet's lower temperature and presence of underground water allow for slow movement of small Venusian plates. This movement enables the formation of mountain ranges and active volcanic activity. Additionally, the planet possesses a magnetic field strength of 0.35 gauss, which is caused by it's active inner and outer core - thanks to it's short rotation period.
The planet's atmosphere is primarily composed of nitrogen and carbon dioxide (CO²), with a similar amount of argon. It features small iron-rich lakes with a slight green tint in its colder regions. The planet's atmosphere appears faintly yellow and dry, with sporadic water clouds surrounding bodies of water and mountain ranges. Sandstorms are prevalent throughout the planet and will occasionally break out and cover the entire planet's surface. Due to it's faster rotation than Earth, storms will have more strength. In the lakes on Venus, there exist microbial and small multicellular life similar to Extremophiles found on Earth.
At a mass of 0.951 Earths, a full day on Venus lasts approximately 19.2 hours, providing a shorter day length than either Earth or Mars. The planet's axial tilt measures at 21 degrees, resulting in seasons throughout it's orbit. The atmospheric pressure on Venus is around 24.2% of that found on Earth. While lacking Earth's mobile plate tectonics, this planet's lower temperature and presence of underground water allow for slow movement of small Venusian plates. This movement enables the formation of mountain ranges and active volcanic activity. Additionally, the planet possesses a magnetic field strength of 0.35 gauss, which is caused by it's active inner and outer core - thanks to it's short rotation period.
The planet's atmosphere is primarily composed of nitrogen and carbon dioxide (CO²), with a similar amount of argon. It features small iron-rich lakes with a slight green tint in its colder regions. The planet's atmosphere appears faintly yellow and dry, with sporadic water clouds surrounding bodies of water and mountain ranges. Sandstorms are prevalent throughout the planet and will occasionally break out and cover the entire planet's surface. Due to it's faster rotation than Earth, storms will have more strength. In the lakes on Venus, there exist microbial and small multicellular life similar to Extremophiles found on Earth.
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Yes, I'm sure they would have been noticed and recorded in any serious astronomy (Egypt, Babylon and later). In Greece geocentrism and heliocentrism were first debated but I think the Martian moons would be a strong argument then so that more philosophers would prefer it, and geocentrism wouldn't have become the dogmatic position like in Renaissance Europe. But it wouldn't change that much on its own, except make it easier for Galilei. To deduce the law of gravity Newton needed the knowledge of the elliptical orbits, and noticing that was only possible with telescope lenses, so you wouldn't get earlier scientific advances from that alone... unless some unknown genius watches Mars and its moons on a dark night and gets some inspiration from it, who knows?
And I like your Venus, hostile but interesting, especially the lakes and extremophiles there.
In fact, Kepler deduced his laws from observations by Brahe, which did not use telescopes (they had in not been invented yet). Now, this doesn’t mean that the Greeks or other early peoples could make the same discoveries, because Brahe used extremely sophisticated techniques in his measurements; indeed, comparing favorably with some early telescopic observations. But it does show that telescopes as such are not necessary.
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@hurax @Workable Goblin
At least for these changes, I am thinking that Mars could be around 1 and a half times the Mass of Earth. I don't think that would affect the orbit all that much? At least for Mars's appearance, my goal is for it to be somewhat-ish similar? Though would that really be possible with a thicker atmosphere? Either way I potentially imagine something similar to Duna from Kerbal space program, with large icecaps covering a good portion of the planet's surface with an equatorial area that is warmer (and possibly slushier, if that makes sense). The Moons of Mars, with Phobos being Ceres mass and Deimos being Ceres mass. What I can perhaps change about that, is have Deimos orbiting at half the distance from Earth to the Moon, with Phobos orbiting half of that. Deimos going around Mars once every 13.5 days and Phobos going around once every 6.75 days. Am not sure how noticeable that would still be.
My intention on Venus is it being a warmer / wetter version of our Mars. You'd be able to go there and not have to deal with a pressure suit, I think. Humans would likely aim for the poles where it isn't so hot. Travel time from Venus to Mars would be quicker. I imagine it gets pretty cold at night, though. The seasonal variations probably add to that.
At least for these changes, I am thinking that Mars could be around 1 and a half times the Mass of Earth. I don't think that would affect the orbit all that much? At least for Mars's appearance, my goal is for it to be somewhat-ish similar? Though would that really be possible with a thicker atmosphere? Either way I potentially imagine something similar to Duna from Kerbal space program, with large icecaps covering a good portion of the planet's surface with an equatorial area that is warmer (and possibly slushier, if that makes sense). The Moons of Mars, with Phobos being Ceres mass and Deimos being Ceres mass. What I can perhaps change about that, is have Deimos orbiting at half the distance from Earth to the Moon, with Phobos orbiting half of that. Deimos going around Mars once every 13.5 days and Phobos going around once every 6.75 days. Am not sure how noticeable that would still be.
My intention on Venus is it being a warmer / wetter version of our Mars. You'd be able to go there and not have to deal with a pressure suit, I think. Humans would likely aim for the poles where it isn't so hot. Travel time from Venus to Mars would be quicker. I imagine it gets pretty cold at night, though. The seasonal variations probably add to that.
Beautiful.
And embarrassing me because I totally forgot about the Mars thing...
As well as other stuff I should post on other websites.
But anyway.
Why is the atmospheric pressure and gauss value so low?
I just chose values randomly. If you think they are rather low, what do you think they should be? And if you could do Mars, it would be very helpful for me. Thanks!
Don't think there was enough material to support a 1.25x Earth sized planet there. Especially with the likes of Jupiter back then almost reaching 1 AU of orbit.
Would also depend if it has the same composition as OTL Mars or the same one Venus and Earth have.
The later together with the greater distance from the sun would allow for a much greater atmosphere, even greater than Earth's, especially I could imagine higher amounts of hydrogen remaining.
Probably sub to close slightly above 0°C temperatures? Would need to look deeper into that.
But imagine at least a bigger Earth that is has an ocean of ice slush, at best even a fully liquid ocean.