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Cake day: June 4th, 2023

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  • Tlaloc_Temporal@lemmy.catoScience Memes@mander.xyzSad Ganymede noises
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    6 days ago

    200+ dwarf planet candidates. Lots of them have very low densities, and most are too far away to know hardly anything about them. Pluto was only confirmed to be in hydrostatic equilibrium with New Horizons, and Quaoar has a Dwarf Planet name, but probably isn’t in hydrostatic equilibrium.

    It’s not the specific bodies I’m worried about, it’s a useful idea of a planet. Finding dozens or hundreds more of them should be exciting, not a reason to throw up our hands and disqualify them.


  • I think “Planet” should be a gravitationally rounded mass that’s not a star anyway. Those can be divided into rocky and gaseous, and further divided by principal composition.

    Smaller than that isn’t usually worth having a name, but moons can be just as interesting as free orbiting planets.

    The distinction between minor and major planets is decently clear in our star system, but if we define it poorly it won’t help us understand other systems or why the major ones are important. It’s definitely not enough to disqualify minor planets from being full planets though. Go ahead and declare 8 major planets arbitrarily, but don’t try to justify ignoring the other few dozen planetoids poorly.



  • Ceres would be a way better start. Lots of water for shielding, consumption, and fuel; easy access to asteroid orbits; and a shallow gravity well to make transport easy.

    Similarly, many of the icy moons around the gas giants would be good, also with decent mining, but better science opportunities too!

    Our Moon is good too. Close, big enough to not need zero gravity setups. That’s actually about it really, it’s just right here. May as well do Orbit I guess.

    Start with Antarctica and the ocean floor. That’s still 80% as difficult, and rescue can take 30 minutes, not 3 days or 10 months!



  • 1kg of oxygen is a good estimate, humand need 0.5-1kg per day.

    Astronaut calorie budges is a bit higher than average, as would be for labouring humans. About 3000kcal, or 12 MJ.

    I think more important than the raw energy and oxygen is sourcing the water, cleaning the water, producing the energy to electrolyse and heat, and maintaining the equipment necessary to do so. And that’s assuming all food is shipped in.







  • Tlaloc_Temporal@lemmy.catoScience Memes@mander.xyzSea Level
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    26 days ago

    The Sol-Jupiter system would have a bary center just 7% outside the surface of Sol. The effect of all the Gas Giants together can either center the syster in Sol’s core or move the barycenter 120% outside Sol.

    The really weird thing is that the part of stars outside the core is more like an atmosphere. If the star gets hotter, the parts outside the core can expand. This is happening slowly as Sol’s core fills up with Helium and becomes denser, which fuses Hydrogen faster. So despite weighing less, the Sol-Jupiter barycenter will be engulfed within Sol’s envelope. Once Sol stops fusing Hydrogen in it’s core, the core will shrink and heat up, fusing Hydrogen in a shell around the core, which will cause the envelope to grow and engulf Venus and possibly Earth directly, and definitely contain the full system’s barycenter. After that it will release a bunch of mass in a planetary nebula, which will cause it to shrink a lot, and the remaining planets will probably orbit much farther out, which would throw the barycenter waaaayyyyyy outside of the white dwarf left over.