Alternate Planets, Suns, Stars, and Solar Systems Thread

Discussion in 'Alternate History Maps and Graphics' started by SaveAtlacamani, Feb 19, 2014.

  1. Jürgen Well-Known Member

    Joined:
    Jul 16, 2016
    [​IMG]

    This is a experiment inspired by this map (https://www.deviantart.com/thobewill/art/The-Centauri-Highway-738041408)

    The World of Nyx

    Nyx are a rogue Ice Giant lying 1,7 light years from the sun toward Barnard's Star, it was discovered in 2067 CE. When humanity expanded into the Oort Cloud it became one of the first colnisation target and human ships arrived around the rogue planet in 4511 CE. They had already discover that Nyx had several moons,but some surprising discovery was found. Nyx had five moons: Hypnos, Hecate, Morpheus, Asteria and Phantasos. Hypnos and Phantasos was both Earth size, while Hecate was Mars size, Morpheus and Asteria was the size of the Moon. The was likely more moon earlier, but Phantasos was a captured rogue planet, which had thrown any other moons out of the lunar system. The three inner moons was all frozen with no atmosphere, Hypnos had the least water and had some dry land, while Hecate and Morpheus was had a deep ocean, Astria are a twin to Titan. Phantasos on the other hand was unique, it was a cold version of Venus weith a very thick atmosphere and a sea level pressure of 80 bars. Together with its very active vulcanism, this result in a surface temperature of 9 degree celcius. This was a incredible discovery and while the planet was lifeless, humanity have introduced a modified biosphere on the planet, this biosphere depend mostly on chemosynthesis and kinosynthesis for energy.

    Moons

    Hypnos: While less interesting than Phantasos, Hypnos are the centre of Nyx, home to 1,8 billion people, it's the second biggest human settlement outside Sol. The population live underground in a vast number of cavern, which areas are slightly bigger than Australia.

    Hecate and Morpheus: Both are lightly populated, only 12 and 7 million lives on each. They live between the water and surface in cities in the ice. Not a lot difference between the world. Both use O'Neils Cones to ensure 1G.

    Astria: home to 171 million people, Astria are in many ways the industrial powerhouse of Nyx, the population mostly live in floating cone shaped cities.

    Phantasos: Home to 981 million people these vast number of people dwell in floating cities, these are the more traditional flying cities in the cold upper atmosphere, and mostly they mine the atmosphere for raw materials.

    Other signifcant sight in Nyx lunar system:

    Nyx itself are home to vast gas extrating industries, and around 150.000 people dwell in its atmosphere. These people mostly live here withot family a few month until they can return with a fat pay check.

    Patel Station home to the local lightway station, here Lightway vessels arrive several times a year.

    Hanseniv Yard, the biggest shipyards outside Sol, their ships are exported to other settlements in the region between the Oort Cloud of Sol and Barnard

    Reposted from the map thread
     
  2. Vlad von Carstein Chaotic Good, Worldbuilder

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    My Throne-World of Drakenhof
    I like this. Question: what is an “O’Neill Cone?” Because if it’s a way to create higher gravity zones on planetoids too large to just hollow out and spin like a giant O’Neill cylinder I’m interested for a story I’m writing
     
  3. fasquardon Cosmonaut

    Joined:
    Sep 24, 2012
    Have you encountered Isaac Arthur's videos? If not, if you are asking about O'Neill Cones, you'd probably enjoy them.

    And good luck with the story!

    fasquardon
     
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  4. Jürgen Well-Known Member

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    Jul 16, 2016
    @fasquardon link explain much of it, but it's fundamental a O'Neil Cylinder for places without microgravity, it's slightly cone shaped downward toward the gravity center. It's only really viable on a planet, moon or dwarf with a low gravity, if we get Mars gravity, it's not really practical any more. Through there's other constructs which could deliver the same effect on Mars.

    So as example you bore down a hole in the surface of Ceres, in the this hole you place this rotating cylinder, but make the cylinder slightly bigger in the top than bottom, this also mean at the bottom you can can create a curvature, which allow people to walk from the spin "gravity" to the normal gravity, allow a pretty easy access point in the bottom. Another major benefit with this model are that the planetoids deliver protection from radiation. While it can function in a place with atmosphere, it's better in a place without one.
     
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  5. metalinvader665 Well-Known Member

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    Wouldn't the atmosphere have to be totally different than Venus to be a "cold Venus"? Because the CO2 atmosphere would rain down and turn into oceans until the atmospheric pressure hit 5.1 atm (beneath which liquid CO2 can't exist). So it would have some very deep CO2 oceans (and some frozen parts cold enough for dry ice) and a rather thick and heavy atmosphere, but not quite a cold Venus.

    I though the modified O'Neill cylinder (vase-like in design) would still be perfectly viable on a place like Mars. Isaac Arthur has mentioned it before (as well as on his Mercury video).
     
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  6. Augustine Sedira Service, Family and Wisdom Banned

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    Jul 22, 2018
    upload_2018-7-27_19-44-51.png
    The Planet of Sartemos.
    Thoughts and advice on improvement are welcome.
     
  7. ST15RM Ich bin ein AH.commer!

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    That long continent bugs me. I think it needs to be curved with the projection.
     
  8. Jürgen Well-Known Member

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    Jul 16, 2016
    The necessary size on Mars would make it unviable and the atmosphere would demand continued influx of energy to keep it going. Instead you could go with a thinner structure like a carrousel lying down, it would still demand energy but a malfunction wouldn't be as disasterous.


    As for cold Venus, I'm talking about the air pressure at sea level, not a similar atmosphere.
     
  9. Augustine Sedira Service, Family and Wisdom Banned

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    Damn, I have completely forgot about projection.
     
  10. Gryphon a constant cry for help

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    Columbia district
    This isn't so much an ATL map as just a really bad OTL map (I was doing a lot of freehand and not a lot of calculating), but this is an approximate map of the 288 brightest stars (everything under magnitude 3.50, plus a marker for the Pleiades) by equatorial coordinates, set on one of the older Worlda scale maps.

    It's more a proof of concept of a way to make a star map than a real attempt at an accurate OTL map, and I can only ask you forgive my errors, which I assume to be numerous. (Note that a lot of the weirdest looking things- the Big Dipper, Cassiopeia, Centaur, and the Southern Cross- appear at the top/bottom and/or edge of the map, both places where distortion is heavy and I had to do more than the usual fudging; this is an unfortunate side effect of that coordinate system. On the other hand, Orion is lovely!)

    [​IMG]
     
  11. Dorozhand Queer Maoist

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    Anti-Binarism Cultural Revolution
    Silly observation, but I just noticed that the inner system of Huitzilopochtli looks oddly similar to the red dwarf system TRAPPIST-1, including three planets in the liquid water zone.
     
    Last edited: Sep 8, 2018
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  12. michaelk156 God of Aephlera

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    Jan 12, 2009
    Aephlera_demo.png A world I decided to start creating on a whim. Not sure if I'll return to it...
     
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  13. JohnWarrenDailey Well-Known Member

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    Oct 22, 2015
    On my alternate Earth, its moon has a diameter of 3,274 miles and orbits the planet from a distance of about 665,000 miles. A five-mile-deep mantle separates its rocky crust from its core made entirely of iron. Questions follow:

    1. Will Earth still rotate at 24 hours and revolve around the sun at 365 days with a moon of this size at this distance?
    2. How quickly will this moon leave Earth's orbit?
    3. How big and how bright would it look in the night sky?
    4. How long would one lunar cycle--new, waxing crescent, waxing gibbous, full, waning gibbous, waning crescent, new--take?
    5. How would tides and eclipses be affected?
     
  14. Ashtagon Very Well-Known Member

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    Feb 7, 2014
    I'm afb right now, but gurps first in has all the formulas you seek, at least for those cases where a formula exists.
     
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  15. rexnerdorum Well-Known Member

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    Location:
    Federated American States in exile
    1. If you want it to, yes.
    2. Very, very slowly. It will still take billions of years to leave earth's orbit (actually, it will be more catastrophic than that, but not for a while).
    3. This moon is 1.51x the diameter of ours, or 2.30 times the area. It's 2.78x farther away. Long story short, it will be 0.30x as bright. (relative brightness is area/distance^2)
    4. One lunar cycle will be 136.7 days. It will probably enter an 8:3 resonance with earth's orbit, meaning it will orbit earth 8 times for every 3 years.
    5. Tides will be 0.16x as strong as on earth. Total solar eclipses will not be possible, as the moon is too small (when viewed from earth) to cover the entire sun. Could produce annular eclipses though. Lunar eclipses can still happen.
     
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  16. Gryphon a constant cry for help

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    Out of curiosity, are you taking into account the vastly increased gravity of this essentially completely iron moon? (The calculator I tried said lunar tides would be about 0.46x the strength, plus or minus.)
     
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  17. Jürgen Well-Known Member

    Joined:
    Jul 16, 2016
    A idea to a Scifi setting

    Humanity had turned into interplanetary civilisation, they had begun to colonise the Deep Void between the stars, and send sub-light colonisation ships to other solar system, when they meet the Star Riders. The Star Riders was a younger civilisation than humanity, but they had mastered the Deep Way enable them to travel faster than light between the stars, and when they meet Humanity they meet a opportunity for loot beyond imagination. They conquered the first colonies with ease. But their first attempt to conquer Sol failed. But they wasn’t ones to give up. The vast richest of Sol was a price, they couldn’t afford to slip them by, and invasion after invasion slowly destroyed the Human defences. Humanity in desperation decided to flee, much of humanity fled to the void between the stars, where the Deep Ways was shallow and hard to use. But other fled into the the depths of the Ice Giants of Uranus and Neptune. The Star Riders conquered the Solar System, but they found it near devoid of slaves, while the vast infrastructure of Sol was a price in itself, and the rich biosphere of Earth, Venus, Mars and the Deep Seas of the Icy moons of Sol’s gas giants was a grand price in itself. They had hoped for the vast amount of slaves, which could taught them the knowledge of Human engineering. Now they could do little else than plunder the ruins of Humanity and use the little knowledge that the Human slaves, they had taken in the colonies to reverse engineer some of the technology of Humanity. They knew of the Humans hiding in the depth of the giants and in the Deep Void. But they had little ability to conquer them, the crushing pressure of the giants would crush, them, and they had little ability to travel the Deep Void. As they colonised Sol lording over their Xeno and Human slaves, they feared alien armadas rising from the depth of the Ice Giants or returning from the Deep Void. They send out slow raiders to ensure that Humanity sought away from Sol and the other systems of the Star Riders empire. While fleets guarded the Ice Giants fearing the vast population hiding there.


    In the depth of the Ice Giants, Humanity on the other hand rebuild their civilisation, they lived in large chandelier cities floating among the skies, while factory outpost on the mantle worked tireless producing the goods their civilisation needed, while deep mining into the rocky core which was under unimaginable pressure delivered the few metals and silicates their civilization needed.


    Both Ice Giants was home to close to a trillion people, but they was also civilisation under siege, they could not leave their planets without being attacked by the Star Riders. Communication between Neptune and Uranus was very limited, and the communication with the Deep Void next to non-existing, the information they got about the Deep Void limited to what information they could steal from Star Riders. But they still planned for rising from the Depths to Reconquer the Solar System, but they was forever limited by their inability to understand the Deep Way.
     
  18. merkmuds Singularitarian/Posthumanist/Transhumanist

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    Was this inspired by a recent Isaac Arthur video? Looking forward to seeing more of this setting.
     
  19. HB of CJ Well-Known Member

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    KISS. Swap Venus with Mars. Perhaps also a really big satellite orbiting Jupiter.
     
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  20. metalinvader665 Well-Known Member

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    What are the chandelier cities hanging from? Really really low "orbital" rings in the deep atmosphere, not far above the mantle? Since anything higher up in the atmosphere would get smashed by the aliens. In which case the chandelier cities might instead be growing in every direction.

    I'd also move Mercury a few million km closer to the Sun so it's tidally locked and gets even more solar energy. And fix the weird elliptical orbit too. Maybe reduce the gravity a bit too to compensate for the slightly increased delta-v.