Comment on A complete tier list for our solar system

GreenBeanMachine@lemmy.world ⁨1⁩ ⁨day⁩ ago

• gandalf_der_12te@discuss.tchncs.de ⁨1⁩ ⁨day⁩ ago

  like, i remember doing the maths a while ago and figuring out the following:

  a planet needs to be in a certain mass range (from minimum mass to maximum mass) to be attractive to long-term human setttlement.

  • the minimum mass is given because the planet can only hold an atmosphere if it has a minimum mass of around 10^23 kg because only then the gravitational potential is large enough to prevent the atmosphere from floating away.
  • also, the planet has to have less than a maximum mass, sothat a spaceship can still lift off from that planet. that’s because fuel consumption scales exponentially with planet’s mass, and if the planet’s mass is too big, basically you “hit a wall” in the fuel-over-planet-mass diagram where it simply becomes practically impossible to lift off from that planet ever again. that maximum mass is around 10^26 kg.

  it is remarkable that earth is in this narrow mass range. there’s only 7 objects in the solar system who are in this mass range: earth, mars, the 4 biggest moons of jupyter, and the biggest moon of saturn. that’s why i think that these 7 objects are especially interesting for long-term human settlement.

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• Furbag@lemmy.world ⁨1⁩ ⁨day⁩ ago

  Ganymede and Titan are an easy shoe-in for A tier.

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