Codraroll

I think I've seen a screenshot of those. (source)

Honest translation: "We did it, we don't care, now we want to pretend like we're the victims."

If I'm not entirely mistaken, it's a NOTMAR. NOTAM is "Notice to airmen", NOTMAR is "Notice to mariners".

Make the whole ship out of antimatter. Problem solved. Granted, a few other problems are created instead, but those are outside the scope of the original question.

Are those the Penguin vacuum engines? I remember finally unlocking them and eagerly trying to design all sorts of new ideas with the awesome-looking upper-stage engines, only to realize they barely had the thrust to move themselves, never mind themselves and a fuel tank.

It's approximately the width of each of your fingernails, if you want a body analogy. That also makes your fingernails roughly one square centimeter. But then again, being arbitrary is not a problem, I'd say. The value of a centimeter is not the selling point, it's how it fits in an easy-to-scale system where units fit nicely together in base ten. I could learn to live with inches and pounds if there were simple and easy relations between the various units of length, volume, and mass that make conversions a breeze. Maybe add speed and force to the mix too. But the Imperial system decides to denote some of this in base 12, some in base 16, and some in base 8, or 10 depending on local customs. The common units of length and volume have nothing to do with each other. The more scientific you try to be, multiplying units with each other to work out complex problems, the worse it becomes. Metric is smooth sailing all the way, with the only hiccups arising from the occasional conversion of minutes or hours to seconds. If accuracy is not absolutely crucial, you can even approximate gravity to 10, and density to 1 for most organic substances - it makes a lot of calculations very simple to do in your head. And again, division by fractions is overrated. The value you start with before divisions is rarely a whole number of units anyway.

"Kind of disappointing" is drastically overselling it. Boring as balls, with pretentiousness dripping from every shot. They somehow managed to make space travel monotonous, even while condensing it to the run time of a movie. And that's not even mentioning the various scientific accuracies that permeated the whole movie, of course. It's one of those movies that are more fun to have watched than to watch, because at least then you can find some enjoyment in discussing how much of a piece of crap it was.

To repeat a post of mine from a few years ago:

You prove my point.

All it took was an understanding of the science and political action to mitigate the situation (the Montreal protocol). Some seem to be stuck on the first point without hope of ever progressing.

I know it makes perfect sense and all when you consider it in detail, but with the scale of this assembly I still find it quite mind-boggling that the tall tower will use those black arms to lift that big rocket atop the even bigger rocket. It just seems too big to work like that.

You round it to 1.2, which is nicely divisible by 3, and get 400 g. That's accurate to within approx. 4% (the right answer is 383.33.. g). Bit harder to divide 1.15 feet by three, isn't it? Sure, you can do the same exercise and say it's approximately 0.4 feet, but your tape measure isn't likely to feature decimal feet, so then you'd have to convert it to inches, and that's not a whole number. It's 4.8 inches, or four-and-four-fifths if you like fractions. Five if you want to round it to the closest whole number, but that's rounding the wrong way, so it's more like four-and-a-half. Yet worse if you start bringing other measurements into it. 0.4 of a pound in smaller units, that's not the same number as 0.4 of a foot in smaller units. At least being consistent with base 12 would have been something, but for mass it's base 16 instead. And for volume, a fluid ounce is either 1/10 of an imperial cup, or 1/8 of a US cup, and the two fluid ounces differ by approximately four percent. No logical relation to cubic inches either way, of course, so calculating the volume from length measurements is a hassle and a half. Calculating in base 10 and moving the decimal around is a bit easier, I think.

Will be? They are already. It was, what, +15C in Salzburg last week and the ski slopes are green. Sure the resorts can withstand one bad season every once in a while, but they are coming more and more often, and eventually continued operation cannot be economically justified.

I don't really get the fascination with scaling down by fractions. In practice, very few situations actually call for it. How often do you need to start with an even meter or a kilogram and split it equally into three? Whether it's cooking, science, or construction, the measurement you start with is rarely exactly one unit.

Back in my university days, there was a "greatest nerd contest" featuring participants from the various study programs. One of the questions was who had memorized the most digits of pi. The contestants from physics and mathematics rattled off dozens of digits, while the one from civil engineering stopped after six. When asked about what he thought about falling so far behind the others, he answered: "If you ever need to build a circular structure to a greater precision than one millimeter per kilometer, you are allowed to look it up". That answer awarded him full marks on the question.

That's just language. The half-liter is as ingrained in the language over here as the pint is in the UK. And I doubt it would cause that much critical confusion if the word "pint" became established short-hand for half a liter. Few people would complain about getting 3 cl more beer than they asked for.

Are you suggesting that various Russian sources may at times contradict each other, and may not all be in agreement about what they regard as truth? Never have I ever ...

How hot can it get before other subsystems start taking unacceptable damage? And how hot can it realistically become in there?

It may be timely to ask why it takes 20 years as costs $150/MWh to run a nuclear plant. It's not necessarily because building a reactor is really, difficult and takes a long time. Some navy shipyards build them as a matter of routine. The USS Montana, a Virginia-class nuclear submarine, was laid down on May 16, 2018, and entered service on June 25, 2022. Granted, it was ordered back in 2014, but that still means a fully operational nuclear reactor went from "we should buy this" to "running nominally, captain" in barely over eight years. I doubt it's any less expensive to build a reactor to fit inside a combat submarine than in a peaceful and spacious building on land. Nuclear power plants become so expensive because of the volumes of red tape that have to be involved. Each plant has to be designed from the bottom up. All the parts have to be custom made and individually certified, then inspected thrice over, and the volume of documentation required probably outweighs the building itself, were it all printed on paper. The safety regimen is extremely rigorous to minimize the risk of nuclear disaster, but it's also a huge cost driver. And I highly suspect that many of these safety regulations were imposed after lengthy lobbying campaigns by "nuclear safety interest groups" whose pockets were full of coal money. Combined, they make nuclear power way too expensive and time-consuming to be worth considering, while coal and gas stand out as the cheap and easily available options, without much consideration for the dangers of that industry. I can't recall the source off the top of my head, but a while back somebody found out that more deaths could be attributed to coal mining accidents since 1940 than the entire nuclear sector - including not only the events at Chernobyl and Fukushima, but also Hiroshima and Nagasaki. That's not to say that all safety regulations should be abolished so every Joe's Nucular Family Shop can weld a hat rack in an old boiler to a turbine and create a reactor in their own back yard, but it might be an idea to review the regulations and see whether the accepted level of risk can be heightened a little bit if it means a tenfold reduction in cost.

The problem with creating a grid based entirely on renewables is that it's quite smooth sailing up to, say, 80%, and from there the difficulty of replacing the remaining non-renewables increases exponentially. The demand for electricity goes up and down all the time, and with renewables, so does the supply. Preventing a gap from forming in the wrong direction is the hard part (managing a surplus is tricky too, but easier). You need some sort of storage that works long-term, to give you juice when everyone needs more electricity than the turbines and PV panels don't quite produce enough. This remains an unsolved challenge on a grid-wide scale. Or rather, the "storage solutions" we do have (fossil/radioactive fuels) are not renewable. There's batteries, of course, but those are massively expensive and can't store power indefinitely. They are good for evening out variations from hour to hour, maybe day to day, but on a longer-term basis they are inadequate. Hydroelectric reservoirs are wonderful for energy storage as they can store oodles of energy for a long, long time. However, they require the right quirks of geography, their capacity is difficult to scale beyond a certain point, and long-term forecasting is difficult. The amount of water in the reservoirs is limited by the local rainfall or snowmelt, and it's a bit of an art to determine when to run the powerplants and when to hold back. On the one hand, you want to have remaining water in the reservoirs for when you need it later. On the other hand, you also want to have enough idle capacity to absorb the next rainfall, so you don't have to send water to the sea when the reservoir goes full. Other kinetic solutions, of the "big block of concrete in a mineshaft" variety, are completely off the table. Just try to do the math on how much energy you can store in a one-ton block suspended by a 100 m cable. To put it like that, it's far from enough to justify the maintenance cost of the pulley arrangement. Then there's the solutions that involve some kind of chemistry. Typically hydrogen electrolysis, or methane production. They work, but they are hellishly inefficient. If memory serves correctly, you put 6 kWh in for every 1 kWh you get back, and I'm not sure if that includes the generator efficiency. And then there's the maintenance of the electrolysis plant. So unless a revolution of sorts happens in batteries or fuel synthesis, some base load production will be required to bridge the gap between what renewables can produce on a bad day and the demand for electricity on that same bad day. Some plant that can be fired up to create energy when the other methods don't give enough. That's where nuclear power plants - and to be realistic, probably gas-fired power plants, at least for a long while - will retain their niche for many years to come.

I know of one method that's being explored, although it sounds a little insane. And by that, I mean that the name alone should send shivers down the spine of anyone who dabbled in physics at a high school level or above: Magnetohydrodynamics. The science of the electromagnetic properties of electrically conducting fluids. The concept is fairly simple. Take a magnetic fluid, and move it. This induces a current in wires, like moving a solid magnet in an ordinary dynamo. The plasma generated in a fusion reactor is a suitable medium. This essentially turns the reactor output directly into a generator, which means you'll skip all the inefficient middle steps between heat and electricity. The generator efficiency can be very high, up to 60-70% or so. The science, however, is a bit complex. Take all the problems associated with calculating the movement of fluids, like the Navier-Stokes equations, and sprinkle in all the intuitiveness of Maxwell's equations on electromagnetism. They influence each other. Have fun. And the practicalities are nuts. After all, you're working with plasma, which tends to be rather hot. It's also moving fast, which creates all sorts of funny abrasion problems. And of course, this being nuclear fusion, there's intense radiation everywhere too. You might get slag deposits here and there too, which interrupt the flow, and then Navier-Stokes rears its ugly twin heads once again. But the potential is awesome. If you can build it without something melting and warping.

Paradoxically, fossil fuel companies are also over the moon with these news. It gives them ammo for their own lobbyism campaign. "Mr. Senator, the great state of Befuddlement needs more electricity, and we understand that you want to subsidize wind power to make that happen. In the last couple of decades, solar and wind power has grown in scope to rival the coal industry. But why throw money into the winds when you can have the future? Look here, new technology is on the way: clean fusion, unlimited power from water, so those turbines will be obsolete in a few years! It will only take a few years before fusion power plants are available, we promise. After all, it's 2022, how long can it take to develop fusion power? Instead of spending money to transit into an outmoded form of energy production, stay your hand, wait until fusion is available, and let the Coal'n'Gas'n'Oil'n'Stuff Corporation handle the state's power generation needs in the meantime, like we do today. Letting the status quo continue for a few more decades is definitely the right thing to do, for the sake of our walle-, uh, for the sake of us all." This is because the exact same process used to work in reverse: "Herr Chancellor, the great state of Unnamed European Country needs more electricity, and we understand that you want to build more nuclear power plants. In the last couple of decades, nuclear power has grown in scope to rival the coal industry. But why bother with that scary radiation stuff, when you can have the future? Look here, new technology is on the way: clean wind and solar power, unlimited power from the weather, so those nuclear plants will be obsolete in a few years. It will only take a few years to install enough solar and wind power to make the entire grid green, we promise. After all, it's 1986, how long can it take to make renewables feasible on a countrywide scale? Instead of spending money to transit into an outmoded form of energy production, stay your hand, focus on expanding solar and wind power, and let the Coal'n'Gas'n'Oil'n'Stuff Corporation handle the country's power generation needs in the meantime, like we do today. Letting the status quo continue for a few more decades is definitely the right thing to do, for the sake of our walle-, uh, for the sake of us all." Or the TL;DR: "No, don't do the thing that threatens our market position today! Do the thing that might threaten our market position in four decades, at the earliest, and let us remain top dogs in the present while your eyes are on the future!"

Or for that matter need it. If the warhead can re-enter independently, one might as well make it capable of performing the plane changes to maneuver on its own, instead of relying on a spaceplane to do it before the warhead is let loose. Come to think of it, a missile on an orbital spaceplane would be a very counter-intuitive thing for those who don't know orbital mechanics. Imagine the Hollywood movie: A space-shuttle-like craft in orbit, approaching its target. Some maps and words on a computer screen in the control room shows the target on the ground up ahead. The order is given to fire the missile. The craft's bomb bay doors open, clamps around the missile disengage, and a little piston pushes it soundlessly out into space as it engine spins up. So far, all the standard fare. But then the engine engages, and the missile fires backwards relative to the spaceplane. The engine burns for a few seconds before fizzling out. The first stage is then decoupled, dropping away to reveal ... not a second-stage engine, but the warhead nose cone. And then little streamers of air begin to appear around the warhead, in the opposite direction of the exhaust of the engine that was just discarded. The spaceplane, at this point, is flying sedately over its target or even way beyond, looking backwards at the missile as it plunges through the atmosphere. I think the movie would need a three-minute scene of the nerd character explaining the orbital mechanics, with diagrams, before the director would allow the missile strike to be shown that way.

A net energy gain, but within which system boundaries? The National Ignition Facility has achieved net energy gain in fusion before, by producing more energy in the reaction than the laser delivered to the fuel. However, this was less than the total power of the laser, which again is less than the power required to run the laser, which again again is less than the power required to support the whole experiment. To quote Wikipedia: "The experiment used ~477 MJ of electrical energy to get ~1.8 MJ of energy into the target to create ~1.3 MJ of fusion energy." I guess this time, they created >1.8 MJ of fusion energy, by delivering ~1.8 MJ of energy to the fuel. There's a long way up to 477 MJ still, and they have to go yet beyond that to get an equivalent amount of electricity back. However, it's a way that has to be walked in steps, and it's good news that yet another step has been taken.

I take it the balloons are inflated for celebrating the return? They don't seem to be needed for buoyancy. (okay, I guess they would be if the craft somehow ended upside down and had to right itself, but as-is, they look a bit goofy).