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Its interesting. The thread about how human inventions got started has morphed into a discussion about our feline masters. WE DID IT ALL FOR THEM LET US CONTINUE THE GRAND CLIMATE-WARMING WORKS, SO THAT THEY MAY EVER BE SNUG AND COSY

And people who haveWOAHWOAHWOAH Imma stop right here...

If it were moving through air, or water, it would have a rounded stern. But a boat moves along the interface between air and water, so the optimum shape is subject to more complex factors. You will usually find though, that the part of the stern which is under the water does conform more to the familiar teardrop geometry. Sometimes extreme hydrodynamic efficiency may also be sacrifices for things like ease of steering or better positioning of propulsion gear. Submarines need to be quiet (inefficient shapes are noisy), and so maneuverability takes a hit for better streamlining.

Isnt that the whole topic of the study lol And yes, I knew what a knob was, I had a british childhood A Hampton Wick, right?

Are you sure its not? Arent you being overconfident? How can I be sure? Am I being overconfident? Can I be sure of anything now? Thats what I was talking about

Clock speed has not been the go-to measure of performance of single cores since Pentium chips. When they brought out the "Core" range, clock speeds dropped dramatically, but performance leapt upwards. You really need to see some benchmark tests to make good quantitative comparisons these days.

Totally agree.

Precisely.

Im having a real problem with recursive logic here because Im assuming most commenters are male.

The answer to that is down to the engineers and scientists constructing the rocket. But for my given answer above, its not relevant. If all you want to do is stop a failing rocket from going off-range, asymmetric shutoff is less of an issue, and if we're talking crewed vehicles then there are already obvious safety concerns such as escape in the first minutes of flight. I agree that solids are less appropriate fro crewed launches:- Can any pair of widely seperated boosters be shutoff in such a timely manner? Its not a trivial process to clamp down on enormous fluid flows either. But for what its worth, the blow-out shutoff on the minuteman booster was extremely punctual as it was part of the aiming process - by modulating the impulse you modulate the distance the warhead flies and very small time errors - or residual thrust - could result in large aiming errors. *** Which is what I meant when I said:

As long as we skip "Human 2000" and "Human Vista" heuhehuehueheuhue

Its a good point. Greed, selfishness, a propensity for violence, the "toxic patriarchy" that is the subject of so many civil rights movements today - even some things not exclusive to the male sex - can all be argued as being extremely effective survival measures as well, genetically speaking. I think it goes without saying that we would do better without them today, but we may not have ever become the dominant species without many of the things which today we regard as bad, or even *evil*.

Ok so some push-back, and on examination, perhaps I should not have typed "WAY" in all-caps, twice But solids *are* the cheap option. And I wasnt using KSP as my yardstick either. Its not merely about price-per kilogram of fuel, its about how much it cost to get your payload into the desired orbit. How can anyone play KSP and presume that cost can be derived from a single value like price per unit of fuel? Solid might have poor Isp, and they might be more expensive dollar-per-kilo (although I had a lot of difficulty confirming just exactly how expensive the average SRB is, nor is it particularly easy to find quoted prices on bulk amounts of what are essentially explosives....I may be on a few more watchlists) but they are cheap in terms of dollar-per-unit-thrust. And some more things: You really cannot discount the simplicity of their construction. Nor can you ignore the development costs for solids, which are certainly much less than that of liquid engines and does have an impact on the cost of launches even well after development is complete. Rocket scientists gots to gets paid. Kerosene, one of the safer liquid fuels, is easily stored...only compared to things like cryogenic liquids or toxic fuels like nitric acid. Kerosene is still a hazardous liquid that requires specialised site safety measures. Producing liquid oxygen on site is also quite handy, but this isnt exactly cheap. The fact is it is produced on site because it is such a hassle to work with - its dangerous enough that constructing a specialised factory is preferable to storage or transport. And a liquid oxygen factory is not a safe place, requiring expertise and oversight. Do not ignore how dangerous LOx can be. Solid fuel is explosive. LOx can make your clothes explosive. LOx can make concrete flammable. Not that these are likely hazards - because of safety measures...which come at a cost. Solid fuel *is* dangerous, but for example, it wont spill or flow through gaps, it doesnt form clouds of explosive vapour, it wont flow into watercourses, it cant be easily inhaled or exposed to skin or eyes. Solid boosters can be locked up in a climate controlled shed and largely ignored until needed, transport costs for hazardous liquids as compared to solids are higher. None of these things individually are huge deal breakers but they all add up. Some people say "But they cant be shut down" - I say, for a rocket, this is often an advantage. A liquid engine can fail, and the rocket fall back to the pad - failures in the first 30 seconds are the most feared events. Light off a solid and there is very little on gods green Earth that will stop it from at least going very far away. Solids are extremely reliable, whilst liquid engines require complex active control measures and have many failure modes. Plus others and I, have pointed out that it is far from impossible to shut down an SRB. I will note though that safety concerns change dramatically when the vehicle is crewed, but then this changes many significant factors and man-rating a craft is hugely expensive for these reasons. Some people say "solids cant be tested, only fired" - true, but then an SRB has 2 components: the fuel and the casing, it hardly needs testing. A liquid engine on the other hand can have hundred of components, many with very fine dimensions and tolerances, made of many different materials, often involving huge differences in temperature. They MUST be tested in case it EXPLODES. An SRB is far more predictable in nature. Many of the above things are important factors in insurance policies which is a large part of the price of a space launch. Sometimes a rocket could even be more expensive, but if it gets you a lower insurance premium based on reliability and component failure rates.... Like, do you want the liquid upper stage on your one-off, very expensive, important satellite? Or do you want the very simple, solid-state booster that has worked on hundreds of launches. Even if it means a slightly larger lower stage, the solid is often the right choice. I will admit though that after some research, the difference in cost is - as far as I could tell due to difficulties mentioned above - not as much as I had thought. Dont make the mistake either, of assuming that I am trying to say that solids are better/cheaper in all situations. Im only giving a rationale for why they are ever used at all. Manned and unmanned flight must be treated seperated. Could multiple SRBs be shutoff? Of course, certainly. Can they be shut off whilst saving an intact payload? Thats much more difficult - but it is not exactly easy with liquid engines either. But multiple SRBs *can* be prevented from running out of control, though it may be easier/simpler to engineer the flight so that their maximum splashdown footprint is all within a safe area. *** Why are LESs solid fuelled? Because you can get monstrous thrust. Because they can be relied upon to fire exactly when you want them to. Because Isp efficiency is a tiny factor in this context.

Here's a thought - Rockets are not designed for maximum dV efficiency. Rockets are designed for maximum cost efficiency. Those two different design imperatives result in different looking rockets. Solids are WAY cheaper than liquids. WAY.

Here's your... Sorry, couldnt resist ...I'll show myself out.

I have some thoughts: Generations don't run in sequence: one, then another. Its a smooth spectrum of change. "Blame", if we're gonna call it that, is spread across many "generations", for example - if kids today are some way or other, it has something to do with their parents. And it also has to do with the kids a few years older (and their parents) and the kids a few years younger (and their parents) that "kids today" mix with or see or hear.

It'd still be a tough shot to make. So the guy with a gun is sidekick to guy with a bow and arrow? Thats my major problem. Hawkeye can go kick himself too. And every other leather-wrapped, nerd-porn bow wielder too. It just stretches suspension of disbelief too far. If you're a weapon guy (as opposed to a guy with powers) why handicap yourself? Also, a bow makes just about the worst striking weapon I can think of, but they're always whirling it around like ninjas [snip].

Please...can you sum that up for me? This is what I got from it: Antimatter doesnt have exactly opposite spin values for its constituent parts, compared to normal matter, but they are different? Something about spin deciding how it reacts to gravity? In conclusion - antimatter has normal mass properties? Am I close? People seem to be leaning quite heavily on "antimatter clearly has energy, and because E=MC^2 it therefore must also have normal positive mass and therefore reacts to gravity in the expected manner." It was my understanding that that is all well and good but empirical evidence [for antimatter's response to gravity] is for now out of our reach. I would also wager that E=MC^2 is an oversimplification in this matter...no pun intended. The formula itself is a reduction of the full mathematics of mass-energy equivalence and it is not applicable to all forms of mass or energy. Id be the first to admit that this is pushing the limits of my experience, I have so far merely been regurgitating what I have seen elsewhere over time.

Its more than a charge difference, there are opposite quantum spins as well. While we know antimatter has positive inertial mass, there is as yet no empirical proof that "inertial" and "gravitational" mass are identical things. The maths adds up, but we cannot as yet rule out some things. It is strongly expected that antimatter has the same mass properties as normal matter, but it cant yet be tested.

Well the track-like part was only about 50-100m and the next shortest route would have made a kilometres-longer loop to get to the same place.

So Im driving home after work, accident on the motorway, on-ramp closed. Very annoying. Use "Waze" GPS app to find alternate route. Very busy, takes a long time to navigate to new route. It tells me to take this turn-off. Seems legit, Im on a main road, the turn off is a main road, no issue. Drive, drive drive, 60mph speed limit. Road goes through some woods. Very nice, well-maintained country road to drive along, no traffic, you know the type. The road narrows. Gets narrower. Turns into a dirt track, partially flooded, deep, gravelly wheel ruts. Have to slow down rapidly from about 60 to about 20 (thank you ABS!) then down to a 5mph crawl through water. Did I mention Im in a Fiat 500? Road widens out again, turns back into a well maintained, wide, fast road - a few minutes further on, I turn onto the road that leads to the motorway. What the butt? Its like they forgot to finish building the road? And it wasnt like there were any signs, like "You may want to slow down from highway speeds as the road almost disappears round this bend" It was like I drove through a slice of an alternate universe, 2 bits of legit main road joined with a length of farmyard track? Lesson - on unfamiliar roads, use extra caution, literally anything can be around that corner. Complaining about lack of signage, poor roads or bad drivers wont knit bones back together - or pay for your car. I dont blame the Waze app, it was just joining lines on a map, and it *was* the quickest route.

I have read about communities in South America that use snakes for vermin control in the same way as cats/dogs. I like snakes. Thats such a cool story! I think part of the allure of cats is that there is a mysterious hint of underlying thoughts that you dont get from other animals, perhaps it is mere anthropomorphising but still, its there I mean, that *is* smart behaviour... *** I have read something interesting about Zebras too. It was about why are horses domesticated but Zebras arent? The answer turned out to be that Zebras are essentially total butts to work with.

There is something to be said for the theory that cats domesticated us... ...we feed them, house them, clean up after them, entertain them, and for what? But seriously, wild cats and dogs wouldn't have been existing in the same numbers in every area, some places would use cats for pest control, others dogs. There are other factors in domestication other than cuteness and pest control though, for example in Egypt there was a strong religious factor. Myself Im fond of all animals (with one or two notable exceptions), especially cats and dogs, but if I had to categorise myself I'd be a cat person.

Meh. They both have clear-cut advantages and disadvantages, you select whatever suits the program. Had a glance at the article, I dont really like it. It reads as a breakdown of the differences between liquid and solid - which is fine - but then frames it as some kind of controvercy? Whereas Im pretty sure orbital ATK know exactly what they're doing? Its not like tanks of stored fuel+oxidiser are invulnerable...

waiddasecond isnt he supposed to be like a god with a bow and arrow? Whats he doing with a gun? And surely impossible shots from the rooftops are his whole deal? Maybe I get it, a bit of an internal consistency thing. I mean really though, the show should be called "bullet" and he should have a rifle or a carbine.