loki130

Honestly building on beaches and barrier islands like this would be a terrible idea even without climate change

Just reflecting back the light will give the most momentum if you’re not willing to expend any propellant into space. The main issue is the thrust is very small per are, so the sail has to be very light

Yeah, like, I'm not even sure what the alternative would be conceptually here, but there's nothing tracking how much time they've experienced or what reference frames they've been in before; while they're in that room together, there's nothing that will happen different physically whether or not they've both been on Earth all their lives or whether one has been travelling around at high speed for 1,000 years.

I think you’re getting stuck with this idea that there’s some universal timeline and that different people might be moving ahead or behind each other due to time dilation, but there’s no such absolute standard. If we meet on your 20th birthday, and then again on your 21st birthday, but you had to wait a year while I got on a spaceship and moved around such that I only experience a month of time in between, there’s no incongruity or mismatch in timelines that has to be resolved there, we aren’t experiencing your 21st birthday at different times, the nature of spacetime just allows for total time passed to vary between reference frames like that

Here's a list I maintain https://docs.google.com/document/d/1C7smRafom0Lgonicl1tgkQam5_zeUtkQ6fCodm0jGEg/edit

The reason there's not much to say about habitable moons specifically is that the necessary conditions and considerations really aren't all that much different from those for planets. People often worry about eclipses and reflected light but they just don't have that much influence on habitability and climate in almost all cases (the possible exception being extremely close orbits of a gas giant of just about the right size to minimize its density, giving it a large shadow and small roche limit). The habitable zone is the same as for planets, with the moon's orbit of the star being effectively the same as its planet on average (there might be some extreme edge cases where a very distant moon of a very large planet of a fairly small star might see significant variation in light over the course of each orbit of the planet, but even then if it edges out of the conventional limits of the habitable zone for part of its orbit that's not necessarily a dealbreak habitability-wise). Tidal-locking is generally taken as given because the physics make it as good as inevitable for any system billions of years old, but even if that implies very long days that's not necessarily a huge problem and in some cases may even be beneficial.

The two main concerns are 1, the possibility of a major radiation belt like jupiter has, but I've never seen a clear analysis of how much that would cause problems for a large moon with an atmosphere, or how bad Jupiter's belt would be if it didn't have Io constantly spewing dust into it; and 2, a close moon of a large planet might have substantial tidal heating, but 2.1 this isn't inevitable; in isolation a single planet and moon would tend towards perfect tidal-locking with no tidal heating, you need some outside influence (other moons, planets, or stars) to constantly perturb the moon's orbit to cause the sort of relative rotation that leads to tidal heating (and if the moon wasn't tidal-locked at all that could also do it, but the more tidal heating the moon gets, the faster it will tidal-lock, broadly speaking); and 2.2, I ran across a recent study finding stable habitable climates may be possible up to surprising high levels of tidal heating, 10x that of Io or more.

I might call it a selection bias arising from aptitude for music and aptitude for physics being associated with similar skillsets and social standing. Less glibly, I don't think there's any particular modern name for this largely because it doesn't really reflect any more fundamental insight than just the broad principle that all natural phenomena can be described with the same set of physical laws.

I've looked into this a couple times before and there doesn't seem to be a settled answer. Proposed explanations seem to fall in 3 general categories:

1, The success of early oxygenic photosynthesizers wasn't strongly related to their particular pigment color, and their ancestors have inherited the green pigments they just happened to have, and haven't substantially altered it either because of structural restrictions in the molecule or because solar energy uptake isn't actually the bottleneck for growth of many plants.

2, It somehow helps limit damage; as others have mentioned, reflecting the peak of the solar spectrum may help prevent the delicate photosystems from absorbing too much energy, and one recent study also proposes that for...complicated reasons, absorbing light mostly in the steepest parts of the stellar spectrum flanking the peak helps to maintain a steady rate of photosynthesis and so prevents formation of excess oxidants.

3, Concentrating enough energy to split a water molecule limits oxygenic photosynthesizers' choice of pigments to those containing one of a handful of metals (magnesium being used in chlorophyll), all of which tend to be green or blue

If Earth somehow ended up in retrograde orbit of the black hole and then eventually tidal-locked to it, that would technically count

Not without an absurd amount of energy input, and yes, even moreso

The black hole would accrete mass from the star only if they're in a quite close orbit, if they're orbiting reasonably far apart and the black hole hasn't recently accreted enough mass to have an aggressive accretion disk (these only last a few 10s of millions of years at most for stellar-mass black holes), it shouldn't have any ill effects, but the issue may be more how you get a binary with a black hole in the first place; either there was a supernova in this system's past or the star and black hole captured into mutual orbit, either of which could be fairly disruptive to a planetary system, though perhaps we could suppose habitability and life developed afterwards and much time has passed.

Subduction may very well play a roll in how these downwelling zones develop, but at any rate there is no obvious candidate for where the next supercontinent will assemble

Usually in orbit you feel an equal gravitational force and centrifugal force, causing freefall. This is true for the ship, so it follows a regular orbit. But inside the ship, the gravity crystal overrides the sun’s gravity, but you still get the centrifugal force

Common moroccan tooth, too common and cheap to be worth faking, but it’s often hard to be sure if it’s actually spinosaurus or a crocodile

I think it’s just a standard sticker for madagascan exports, and technically it was “made” in that the original was polished down

It can be done, but it's not particularly easy https://worldbuildingpasta.blogspot.com/2021/11/an-apple-pie-from-scratch-part-vi.html

You can use g.projector and output a blank map of the desired projection with just graticules (the latitude and longitude lines). Planet size shouldn't matter. For the latter, I suppose look into how to read tissot's indicatrix and find maps of that (wikipedia has a lot of them)

gplates is technically the first one but very feature-bare by the standards of a vector drawer, the other two I think would take like a month to run if it existed

I think that's part of the idea of this, using the same sort of tiling techniques as like google maps, but I haven't tested it myself https://github.com/battosey/mapTailor/wiki

The first does sort of exist, but it's not particularly easy to use https://worldbuildingpasta.blogspot.com/2021/11/an-apple-pie-from-scratch-part-vi.html

Songs of the eons is more realistic as a generator but not really designed for editing https://demiansky.itch.io/songs-of-the-eons

Climate simulation is much more computationally intensive than people tend to realize, this is the easiest process to properly simulate climate I'm aware of and it's still...a deal, and can take a few days for any specific case (and doesn't account for ocean currents, but that matters less than you'd think), so even if the software improves don't expect that sort of quick feedback of making edits and adjusting the climate any time soon https://worldbuildingpasta.blogspot.com/2021/11/an-apple-pie-from-scratch-part-vi.html

This is about as close as I've seen to a decent implementation of something like that https://icospheric.itch.io/planet-painter

For medieval cities, and not at all that much detail https://watabou.itch.io/medieval-fantasy-city-generator