KSK

Ahh - thank you! I was being deliberately precise with my 'raising to boiling point' because I couldn't be bothered to look up enthalpy of vaporization. So - 11 seconds of total solar flux to boil off the world's oceans? I think @Scotiuswas in the right ballpark for an hour of same.

According to this website, the sun puts out about 385 x 1024 W or Js-1 The volume of Earth's ocean's is (apparently) 1.4x1018 m3 Amount of energy required to raise 1kg of water from 20 degrees to its boiling point is approximately 335 KJ, so for a cubic metre (1000 kg) that becomes 335 MJ or 335 x106 J So, assuming that I haven't made a mess of my units, the sun puts out approximately enough energy per second to bring all the oceans on Earth to their boiling point. I draw two conclusions from this: 1) It's probably a good thing that we only receive a small fraction of total solar flux. 2) If Superman can absorb one hours worth of total solar flux, he can pretty much do what he wants.

And they probably always will. Objectively, it's quite difficult to paint a fiery explosion as anything other than a failure without going into a fair bit of detail and justification - which most publications or their readers aren't interested in. I did like the one article which reassured everyone that the flight was uncrewed - and that need for a human-interest angle also says a fair bit about media priorities. As for myself, I have these words: SpaceX... the final frontier. That was the voyage of the Starship SN8. It's mission: To demonstrate controlled falling with style; To relight engines and perform an experimental kickflip; To boldly 'splode, like no rocket has 'sploded before!

Any bets on whether they'll reuse the nosecone from SN8 just because? That thing survived an off-nominal landing - it's clearly built to last! Likewise with that landing pad. Seriously though - the flight happened too late for me to catch it last night but damn if that wasn't an *awesome* start to the day!

Nope. The astronaut starts at rest relative to the cylinder. Net momentum is zero. He throws the ball giving it momentum - and himself an equal and opposite momentum. Net momentum is still zero. The ball sticks to the wall transferring its momentum to the cylinder. The astronaut sticks himself to the cylinder transferring his equal and opposite momentum to it in the process. Net momentum is still zero. It’s that reattachment of the astronaut to the cylinder that spoils things. When the astronaut comes to rest (relative to the cylinder), his momentum has to go somewhere. If the cylinder was open at one end and the astronaut flies out of that open end, then yeah it would work. Once.

And on top of all that, @jimmymcgoochiemissed out the part where the ‘road atlas‘ is actually an old-school map, of the correct planet if you’re lucky, with most of it filled in with cartographic art and ‘Here be Krakens’ labels. I forget where this came from but someone described writing as an art where narrating an epic battle can take hours but describing how a single character walks across a room can take days. I can’t speak for our good author but that certainly resonates with my experience. The big set pieces - the cliffhangers, the derring-do, the epic launches, the crazy flights that end up with you crashing through the VAB roof - those parts are comparatively easy because they’ve been sitting in your head waiting to get out. The stuff in between that ties all the set pieces into an actual story with depth and heft and characters you care about - that’s a whole lot harder.

Luminous beings are we - not this crude matter. Rest in Peace, Mr. Prowse. https://www.bbc.co.uk/news/entertainment-arts-55117704

Yeah, blasting a rock into chunks with a laser is probably a tall order, but cutting rock with a laser should be feasible. It may take a while though, so as @mikegarrison said, space sims go for rule of cool instead. Some very simplified notes on lasers based on conversations with a colleague a couple of years back: You've got two main modes of interaction between a laser beam and a surface. Photothermal - where the material under the laser evaporates or sublimes away (think of the laser as a fancy blowtorch), and photoablative, where the material turns to plasma and dissipates. Which one you get depends critically on the power density of the beam at the surface. Typically, a continuous wave laser will operate in a photothermal regime because its difficult to build a continuous wave laser capable of reaching the required power density. Pulsed lasers on the other hand can get around that problem by shortening the pulse width. The actual energy per pulse can be relatively low but because its delivered over picoseconds or even femtoseconds, the power densities involved can get quite extreme. When you're dividing by 10-12 or 10-15, the numbers can get pretty big pretty fast. Whilst photoablation sounds pretty violent, in practice everything happens so quickly that very little thermal energy is transferred to the material that isn't directly under the laser beam, so it's a very precise technique with a whole bunch of applications, including dental or medical applications. For space rock cutting, I might try an array of semiconductor lasers. They're compact, they convert electricity directly into light (as an LED does), they can get reasonably powerful and, if I remember correctly, they're a good choice (if not the only choice?) if you want a fast or ultrafast pulsed laser. One semiconductor laser on its own might not be very impressive but - that's why you have an array of them. Even so, each pass of the laser(s) over the rock won't ablate that much material, so it'll take time to cut off a decent chunk. Not so good for space sims unless you have really dedicated players.

A couple of thoughts. Whatever method you use for breaking up asteroids is going to be very dependent on the asteroid type. A rubble-pile asteroid will behave very differently to a chunk of nickel-iron when you hit it with a railgun round. Whatever harvesting method you use will also depend on the asteroid size. Small ones can be scooped up whole, big ones might be better dealt with by building a mining facility on them, although that does come with its own set of problems. If breaking up the asteroid is the best option then, unless you’re imparting enough delta-V to the asteroid chunks to significantly change their orbit, you’ll end up with a slowly dissipating cloud of asteroid fragments which can be scooped up at leisure. There may be no need for a net. Deploying nets of any size is going to be a non trivial undertaking. Again, very dependent on asteroid composition but a laser might be more of a precision instrument than a railgun. Better for carving off pieces from a larger rock without sending those pieces flying into the distance. For space ‘sims’, gameplay trumps realism, so any space sim asteroid harvesting is probably going to be a bit dumb.

Awww - all the floof in one convenient location.

That’s fair and (seriously) good on you for doing the research and deciding it’s not for you. If more folks did that, gaming forums would be a nicer place to be. And, as I said, my ED combat experience is way out of date so probably doesn’t match up that well to the latest videos. Just as an aside - and I respect your opinion on the game so I’m not trying to talk you out of it - I think Lee Hutchinson over at Ars Technica has it about right. ED really nails the sense of flying your futuristic sci-fi personal starship and the sheer sense of scale involved in flying around the galaxy. But you find the fun in just existing within that universe and doing your thing. There are gameplay loops in there but when it comes right down to it, there’s not much you can’t do in your little starter ship. You can buy bigger ships to make things easier but, as Lee put it, it’s a pie eating contest where the reward for winning is getting to eat more pie. If you don’t enjoy the activity of trading (for example), then buying a bigger trading ship isn’t going to help much. At best it’s a necessary slog to further some other goal, at worst it’s just a grind. That’s not for everyone so yeah, I respect your ‘doesn’t hit any sweet spots’ opinion.

It’s been a while since I last played it but that doesn’t match my experience with Elite Dangerous at all. For me combat had plenty of close-in dogfighting, although I was usually too busy trying to land hits to admire the texturing on my opponent’s ship! I imagine it’s very loadout and player skill dependent though. If you’re good enough to snipe with a plasma accelerator at beyond visual range, then yeah, you’re not going to be seeing much of the enemy. I tended to go with a bog standard pulse lasers and multi-cannons loadout. I suspect my meta is several years out of date but on the other hand I did get to see what I was shooting at.

I'm pretty much at @starcaptain's level when it comes to fusion but your comment about spherical arrangements jogged a memory, specifically, reading the news blurb about this: https://ccfe.ukaea.uk/all-systems-go-for-uks-55m-fusion-energy-experiment/ No idea what the difference between a spherical tokamak and a polywell is, but the former still looks to be under active investigation.

Yeah that’s been bugging me too.

Well the Apollo 16 CSM was named Casper so I’d say that spacecraft and ghosts (friendly or otherwise) have a storied history.

Very nice post. Should be stickied in the KSP2 forum as a reality check for everyone going gaga over interstellar travel.

It almost makes sense when you put it like that.

It makes perfect sense when you get the full explanation but it blew my mind when I first heard about it. There's water ice on Mercury.

The UK - as mentioned in my original post. And the folks that are pointing out that nuclear plants should be cheaper? No doubt but that wasn't my point. Their current costs aren't preventing them from being built (albeit not in great quantities), so unless fusion ends up being orders of magnitude more expensive still (which seems unlikely given the cost of ITER), then there's no reason to assume that cost necessarily be a barrier to building fusion plants. Assuming they can be made to work.

Fission powerplants aren't cheap either and yet they're built. It's not an apples-to-apples comparison by any means but ITER has apparently cost €13 billion (£11.57 billion at current exchange rates) whereas Hinckley Point C (UK nuclear plant under construction) is a £20 billion project. I think the reason for the lack of commercial investment in fusion power is simply that it's still an expensive research project at the moment. Not many companies have the cash reserves to throw €13 billion at developing an untested technology. If and when it's shown to work, then you'll see the commercial investment, likely financed in the same sort of ways that fission powerplants are currently financed, at least to begin with. I agree that fusion powerplants aren't going to space anytime soon. Quite aside from the cost, they're too big. But 'going to space' doesn't have to be the measure of a technology's worth. If we 'just' use sustained fusion for electricity generation on Earth, I'm fine with that. Baseline power generation that's cleaner than fission and lower carbon than fossil fuels - sounds good to me.

Oh gods, what have I done...

Spotted Stellaris going for 75% off on Steam a couple of days ago and decided it would be rude not to try it. Futzed around with a few (now abandoned or on-hold) starts and am progressing nicely in my first proper game. Not playing on iron man yet though, until I've got a proper handle on how the various game mechanics work. I'm playing the United Nations of Humanity and currently enjoy excellent diplomatic, trade, and research ties with the nearest alien faction (peaceful scientific lizards). Once our ruling council have figured out a suitable political structure (i.e. once I've scraped up enough Unity points to unlock the Federations tradition), the Star League shall be founded! Although, given the number of other sci-fi references crammed into the game, I fully expect Xur and the Ko-Dan armada to then show up. At which point the only winning strategy will be to find a primitive world, recruit their finest warriors, and use them as gunners aboard our most advanced starfighters. Meanwhile, our Imperialist rivals (second Human faction) have illegally laid claim to one of our border systems. The 1st Fleet is en-route as a peacekeeping measure, whilst the shipyards are hard at work cranking out Katana II and Longbow class frigates (interceptors and missile boats respectively) for the 2nd Fleet. In the background, our R&D teams are working on a new, destroyer class ship chassis... Checking the map, I see five Imperialist systems that could be usefully acquired. None of them are inhabited but they're all rich in resources. As a bonus, capturing those systems would shorten the Imperial border with our lizard friends, which should make them a bit happier.

Except maybe not the Gentoo that immediately sprang to mind. https://www.bbc.co.uk/news/science_and_environment Apologies - it's been a long week and I couldn't resist the joke.

That's reasonable. Everyone has their version of the Kerbals, from differently coloured humans to weird plant things that release spores when they die. To my mind, part of the fun of Kerbal fan-fic is seeing all the different takes on the kerbals from different writers. Okay, I'm not so comfortable with that. I'm maybe reading too much into your words here but that sounds like 'I'm okay with gay characters but don't make them important ones, okay?' Anyhow, probably better to take this to PMs rather than cluttering up this thread and possibly drawing the Gaze of the Moderators.

Exactly. No particular reason why the default for a fictional relationship needs to be straight. Also , have a quick re-read of chapter 7 - it seems that folks are more relaxed about such things on @jimmymcgoochie’s version of Kerbin. Which is cool.