The Expanse and its compatibility with OA stevebowers Administrator Posts: 10,519 Threads: 420 Joined: Apr 2013 05-19-2019, 03:41 AM (05-19-2019, 03:31 AM)The Astronomer Wrote: I'm pretty sure Expanse was written before we discover that half of Ceres is actually made out of water. The author acknowledged that and even wrote an essay (...or, well, whatever you call it) on that. Speaking about dry Ceres, in EG the 'Cerean' class planetoid is still described as 'rock dwarf'. Might want to change that. If anybody's interested, they could make a new thread in General Setting. Vesta, on the other hand, is mostly rocky. The class should be renamed after that object. Noclevername Enthusiastic amateur Posts: 138 Threads: 5 Joined: May 2019 05-19-2019, 03:47 AM (This post was last modified: 05-19-2019, 03:51 AM by Noclevername.) (05-19-2019, 03:06 AM)The Astronomer Wrote: Now, if you, by any chance, play Children of a Dead Earth, you might point lasers' low efficiency and their inability to run hot resulting in them requiring hilariously big radiators, but real life military lasers are over 40% efficient, so that point is kind of...iffy. TBF, current military lasers are much smaller in scale and lower in power than the ones in COADE. https://childrenofadeadearth.wordpress.c...ton-lance/ Quote:Thermal lensing increases $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$ roughly linearly with input power. This means if you have 1 kW laser with a $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$ of 1.5 (which is reasonable), this means dumping 1 MW into that same laser will yield a $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$ of about 1500 (going the other way does not work, since $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$ can’t be less than 1). ADDED: Also, the Expanse ships don't have radiators. stevebowers Administrator Posts: 10,519 Threads: 420 Joined: Apr 2013 05-19-2019, 08:36 AM (05-19-2019, 03:06 AM)The Astronomer Wrote: Alright, I'll stop beating around the (nonexistent) space bush: I demand a Starlark pic with dem glorious radiators (disclaimer: jk). Thanks in advance  Here's one... Attached Files Thumbnail(s)     Noclevername Enthusiastic amateur Posts: 138 Threads: 5 Joined: May 2019 05-19-2019, 09:34 AM (05-19-2019, 03:41 AM)stevebowers Wrote: Vesta, on the other hand, is mostly rocky. The class should be renamed after that object. Now I'm thinking of Marooned Off Vesta, where the body in question was made of ice. The Astronomer Senior Member Posts: 2,168 Threads: 108 Joined: Jul 2016 05-19-2019, 04:00 PM (05-19-2019, 03:41 AM)stevebowers Wrote: (05-19-2019, 03:31 AM)The Astronomer Wrote: I'm pretty sure Expanse was written before we discover that half of Ceres is actually made out of water. The author acknowledged that and even wrote an essay (...or, well, whatever you call it) on that. Speaking about dry Ceres, in EG the 'Cerean' class planetoid is still described as 'rock dwarf'. Might want to change that. If anybody's interested, they could make a new thread in General Setting. Vesta, on the other hand, is mostly rocky. The class should be renamed after that object. There is already another class named after Vesta: a planetoid that has experienced some volcanic activity early in its life. Since Vesta is the only known asteroid where there is evidence of volcanic activity, we should keep it. On Starlark: thanks for visualizing Starlark's radiators. It's kind of, well what do I say, really straightforward and hydrogen is a vastly superior choice...if not for how it's annoyingly hard to store. I don't know how far tech in OA went at the point, but you still need to keep it liquid, or even solid, and worry about how individual hydrogen molecule could escape from the tank walls through gaps in the tank molecules... On lasers: even if we can't build bigger ones, we can always shove many of these smaller ones together. Is there is any reason a big laser would be less efficient than smaller ones? Noclevername Enthusiastic amateur Posts: 138 Threads: 5 Joined: May 2019 05-19-2019, 04:17 PM (05-19-2019, 04:00 PM)The Astronomer Wrote: On lasers: even if we can't build bigger ones, we can always shove many of these smaller ones together. Is there is any reason a big laser would be less efficient than smaller ones? Per COADE:  Quote:In the end, the primary way to combat thermal lensing is with cooling. And the primary way to cool your laser is to make it bigger. If the proportions of a laser are kept identical, lasers can be scaled up or down with minimal change to the laser’s efficiency or output power. Indeed, you can pump 100 MW or power into a tiny palm-sized laser just as well as you can into a building-sized laser, and they will produce roughly equal beams in terms of efficiency and $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$. The only difference is that the palm-sized laser will melt into slag when you try to fire it. Laser size is mostly a matter of how much do you need to distribute the heat of the laser pumping. And if you want to combat thermal lensing, you’ll want a really big laser. This means laser size is essentially about cooling, and by extension, having a low $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$. And because size is closely related to mass, and mass is so critical to spacecraft design, the limiting factor of using lasers in space is how poor of an $[Image: latex.php?latex=M^2&bg=ffffff&fg=000000&s=0]$ you want to have, given a certain power level. Though the radiator mass needed for the enormous power supplies is the other major consideration. and  Quote:A final way to combat thermal lensing is to use Beam Combining of many smaller lasers. Combining beams side by side increases the beam waist linearly, which defeats the point, but Filled Aperture Techniques can combine beams without increasing the beam waist. However, this technique produces greater inefficiency to the final beam. The ideal way to combine beams is to simply use multiple separate lasers which all focus on a single point. So yes, if you can prevent the mini-lasers from melting under their own energy, and solve a non trivial aiming problem? Then you can have "laser banks". Noclevername Enthusiastic amateur Posts: 138 Threads: 5 Joined: May 2019 05-19-2019, 04:29 PM Can the discrepancy between serious Ceres and the series Ceres be "fixed" somehow? I am, as you can tell, a fanatic about doing so for fiction. --They could just say we're wrong about it in the real world. This excuse becomes weaker and weaker as science marches on and more data becomes available to the reader or viewer. --The rock inside Ceres that we currently think is ice, is some other low density material that has properties similar to ice but is not water bearing. --There's water, but it's somehow unusable or inaccessible. Seems vanishingly unlikely. And dumb. TV executives love that. --We're underestimating the strip mining and terraforming capacity of the Expanse setting, they actually have methods not seen onscreen, to overcome those limitations we discussed. --Aliens did it. stevebowers Administrator Posts: 10,519 Threads: 420 Joined: Apr 2013 06-19-2019, 07:01 AM (05-17-2019, 09:54 PM)stevebowers Wrote: Russell T. Davies' new series, Years and Years, is about the near future, and has one character who wants to become a transhuman; this is probably a bit early for that sort of thing, but at least it is out there. Just watched the last episode- someone gets uploaded at the end... this series has been a pretty good exploration of the transhumanist mythos, with some good RTD moments thrown in. « Next Oldest | Next Newest »

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