Post AlEbxoASaYjzkJ7moi by Aaron_DeVries@mastodon.social
(DIR) More posts by Aaron_DeVries@mastodon.social
(DIR) Post #AlEbxkLIoJ2LsmAOA4 by Aaron_DeVries@mastodon.social
2024-08-22T16:37:09Z
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Tossing around ways to incorporate practical interstellar travel in a more hard sci-fi setting. And it occurs to me you can do sublight interstellar travel over more reasonable expanses if you make the setting a globular cluster.The avarage distance between stars can be less than a light year. Some at distances comparable to the width of our solar system. So traveling between systems could take as little as a few months with a torchdrive, or couple years for further destinations.
(DIR) Post #AlEbxktgkSXhbQFql6 by isaackuo@spacey.space
2024-08-22T17:10:09Z
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@Aaron_DeVries Yes, and also Omega Centauri is a cool sounding name that lets you have the inhabitants argue about whether they are Omegans or Centaurans.Furthermore, planetary bodies are likely to just be loosely wandering around in the core (where stars are close to each other). So you don't really need to travel from one star to another. You can just travel from rogue planet system to another - a much shorter distance.OTOH, maybe there wont' be much planetary material.
(DIR) Post #AlEbxlci34YTr3Jnvs by isaackuo@spacey.space
2024-08-22T17:13:23Z
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@Aaron_DeVries Note that a globular cluster will have a LOT of white dwarfs, and these have a particularly strong Oberth effect. With an escape velocity of on the order of, say, 5000km/s, it's suitable for easy cheap propulsion up to thousands of kilometers per second.Really, these white dwarfs are perfect for powering serious space trade in a globular cluster.
(DIR) Post #AlEbxmBnwaczbtjpdQ by Aaron_DeVries@mastodon.social
2024-08-22T17:18:26Z
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@isaackuo exactly, there's a lot of interesting things that could be incorporated in a globular cluster setting. Entier colonies could latch onto small bodies that drift about, jumping to a new one when the one they are on is going to get too close to a star.Panspermia could be a big driving factor for life spread. Very old planets, chaotic planets with unstable environments.
(DIR) Post #AlEbxmy13LC01QIKmW by isaackuo@spacey.space
2024-08-22T17:35:01Z
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@Aaron_DeVries Note that lighter stars, like red dwarfs well tend to be further to the periphery and much further apart from each other. These may also have more planetary material and also generally have a more stable environment for life to evolve.So it might not be so conducive to panspermia.One idea I like is of Europa-like biospheres powered by tidal forces (which can provide power on gigayear timescales). But the thick ice crusts are VERY ungood for panspermia. ...
(DIR) Post #AlEbxnjWCjBqOkWGp6 by isaackuo@spacey.space
2024-08-22T17:37:39Z
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@Aaron_DeVries ... I mean, being powered by tidal forces is great for a Europa-like moon orbiting a rogue brown dwarf or gas giant. It means the biosphere has nice stable conditions even as the planetary system gets flung out of its home star system, and suffers bouts of darkness and extreme radiation as they pass by stars, pulsars, etc.The thick ice crust is great for shielding the biosphere from all sorts of badness. But for panspermia ... no. Just no way.
(DIR) Post #AlEbxoASaYjzkJ7moi by Aaron_DeVries@mastodon.social
2024-08-22T17:42:07Z
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@isaackuo I was thinking the periphery would be a better place for intelligent life just because the spacing would be a bit higher. Planets there would be more stable for longer. But further in simpler life could be found.Ice shell moons I belive are probably the best places for life in general cluster or not so no argument here. Panspermia depends on how active and thick the shell is and how offten it resurfaces.
(DIR) Post #AlEbxoeEnqYnEf3ZEO by isaackuo@spacey.space
2024-08-22T18:10:17Z
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@Aaron_DeVries Ah, now that you mention it ... for your own setting you can make up whatever you want in terms of how quickly ice crusts move material around.AFAIK, the latest scientific estimates are not very favorable. This was in terms of transport of surface oxygen trapped in ice to the subsurface ocean.Basically, sputtering of ice creates oxygen at the surface, as hydrogen preferentially escapes. This could be good for life if the oxygen can make its way to the ocean. But it doesn't.
(DIR) Post #AlEd1boYYlU6XsFu7c by nyrath@spacey.space
2024-08-22T19:34:44Z
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@isaackuo @Aaron_DeVries I was going to mention that Ian Douglas (William Keith) sed that in his scifi novel Star Carrier. Until I discovered that was mentioned in the Wikipedia entry...https://en.m.wikipedia.org/wiki/Omega_Centauri#In_fiction
(DIR) Post #AlEwXkryKK8T1btYa8 by tkinias@historians.social
2024-08-22T21:54:57Z
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@isaackuo for my own setting, I’ve assumed that (a) life is pretty common under the ice in tectonically-active frozen worlds—they maybe even make up the majority of life-bearing worlds—but also (b) those ecosystems are totally anaerobic—so while there may be ‘interesting’ multicellular life, the systems are way less energetic than aerobic ones@Aaron_DeVries
(DIR) Post #AlEwXm6Bkx6MpzYQNc by tkinias@historians.social
2024-08-22T22:02:47Z
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@isaackuo but do we have a sense for *how much* oxygen might be hanging around in the atmosphere?earth-size or larger planets out past the HZ could hold on to pretty substantial atmospheres, so are we talking like a few millibars of O2 or something more like the kind of O2 pressure you’d get from a photosynthetic biosphere?@Aaron_DeVries
(DIR) Post #AlF4hhITGPeITRXdr6 by isaackuo@spacey.space
2024-08-23T00:16:43Z
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@tkinias @Aaron_DeVries I don't know how solid this scientific research is, but evidently deep sea microbes can create oxygen via some process that's not photosynthesis.https://oceanographicmagazine.com/news/deep-sea-microbes-oxygen/If we assume a Europa-like biosphere with similar microbes creating oxygen, it might pool in gas pocket upside-down "lakes" against the ice crust. While this wouldn't be a full sized atmosphere, the pockets could be big enough for aliens to utilize fire for various processes.