p1t1o

A *semi*-autonomous car with a *human driver* in it, killed a pedestrian in a collision recently, and the moral debate is already hotting up.

I think its too far of an extrapolation. Especially if you compare the recent trend - in the past robotic servants were all the rage, all you need do is check out all of those charming "predictions" of what the future would be like from 50-100 years ago. But now, people loathe the idea of computers controlling autonomous weapons, so there has been a negative trend. Sure in the future, it might reverse, but it is equally reasonable to assume that with the exponentially increasing complexity of machines, that people balk even more about them controlling aspects of their lives. One could say that war fought by machines is preferable because fewer lives are lost...until a machine goes wrong and we try and figure out who to blame. Because in the end, even in the far future, we are still human. And if we arent, then all predictions go out the window anyway. So I just tried to present good reasons why, and good reasons why not, how the future reacts is anyones guess. IMO. Just after WW2, there were many people of authority who assumed that manned air combat was a thing of the past, as they had just started to invent missiles. It was assumed that all air combat would be via missile from then on, and look what happened. We could easily have fully autonomous combat drones today, the only reason we have human drone pilots is accountability (and because the distance is still short enough to keep remote control feasible). Having said that, there is early work being done on naval drones that would have more autonomy than the UCAVs we are used to, even drone submarines which by necessity would need to have a lot of autonomy as the communication links would be very poor. Modern missiles could be thought of as fully autonomous combat drones with the power to make lethal decisions (some, for example, can visually search for programmed targets and call off an attack if none are found. Some can even attack as a coordinated "swarm"), but I think they are sufficiently different as any discussion of them would muddy the waters.

Ideally, space warcraft would not require human crew because of huge physical limitations. For one thing, you'd have to install a bunch of toilets, which are not particularly useful in battle and weigh a lot. Reaction times are not really relevant because humans would always be operating in conjunction with computers. Even a 20th-century era "Phalanx" CIWS is not "manually" operated. There are two reasons to have human crew - Accountability - Who is responsible for waging the war? Who makes the decisions? Obviously, there does not need to be a general on every space fighter, but there needs to be a human in the loop somewhere, otherwise who is fighting this war? You can keep the humans off-ship, but then there are time-lag issues. You can program a computer to make these decisions for you but someone has to "pre-make" those decisions when doing the programming, and there are many cases where you'd want the programmer to have much more up-to-date information. Essentially, you may want computer operators on-site, with access to sensor telemetry and without any lag between input and action. Even an AI has to be tasked, and there are advantages to having the person giving the orders nearby. Because you need them - maybe in the future we will have access to AI that can reliably be left in charge of waging a battle without supervision, but that is a tall order, and until then, a human brain is the best AI ("I"?) we've got. Oh sure, you can extrapolate infinitely into the future and say "Space wars dont need humans because computers are faster and make better decisions" And one could easily say "Space warships will be obsolete because by the time we can build good ones, we will be able to shoot them down from surface installations" In other words, extrapolating that far into the future, you can justify almost anything. But the reasons for "Why would we need human crew of any kind?" and "Why wouldn't we need a human crew of any kind?" will always be valid. It may easily be the case that in the far future, a whole fleet can be commanded by one on-site human. And it is also the case that at some point in the infinite future, entirely automatic wars will be fought with barely a human noticing. But I think we can say for certain that fleets of huge space battleships each with a crew of thousands, is unlikely to ever occur.

Here's a fun story about my first "date" (I had had a girlfriend and stuff before, but at uni you dont really "date" so much as...fuse? I dunno, anyway...) So 1st date goes quite well (met on dating website, not especially relevant) and shared a kiss on the lips at the end. Later, me arriving for 2nd date, am wondering how I should greet her? I go for what I intended to be a brief kiss, on the lips, following on from date #1. She offered her cheek. So what we got was me smearing my lips broadly across her face, starting somewhere near her mouth and ending not far from the corner of her eye. Her almost complete lack of [visible] reaction spoke volumes. This is one of my "lying awake at night" memories. Even now Im sitting here thinking "Maybe one day the ground will swallow me up and I wont have to remember that again".

Im not sure if you can really speak to his intentions, but either way, nobody is actually getting locked up.

5 years probation is not the same as 5 years in prison. I dont know much else about the story - so its certainly possible to be some kind of screwup - but I've heard too much of "it was juuuuuuuuuust a joke" being used as an excuse and it drives me up the wall. You cant say whatever mindlessly offensive or threatening thing and then just "just a joke lol" and have all consequences washed away. It almost makes it worse, that you can hurt someone, then think that a magic sentence can make your actions just disappear, thats highly offensive just in-and-of-itself. On the face of it, without any other detail, just on hearing "he even said it was a joke" Im inclined to think 5 years probation was sensible, but I admit I have only read a couple of lines about the case so my information is lacking, but Im not particularly inclined to find out more. PS: I hope your cat gets better

2km/s sounds pretty slow for a limit on electronics, I've never heard of one like it for coilguns. I mean, there will be a limit to switching speed on particular types of hardware, but there are all sorts of things you can do to achieve faster speeds. For one thing, after a minute or two of googling I found an example from 4 decades ago (1978) which used only a single coil, but accelerated a 2g projectile to 5km/s (within a space of 1cm!!) https://journals.scholarsportal.info/details?uri=/00189464/v20i0002/239_mspia.xml So yah, that 2km/s limit is 100% BS. FunFactTM: Super-fast switching hardware is often controlled under so-called "dual-use" regulations, as it is a key enabling technology that allows efficient nuclear weapon designs. http://nuclearweaponarchive.org/Library/Pasley1.html For your static charge idea, you neatly left out the part that explains how you accelerate the static charge that is propelling the projectile! Anyway, it sounds pretty similar to a coilgun but swapping magnetic fields for electric ones. Seems workable in principle but I wonder if static fields can be manipulated with the same speed and power as magnetic ones?

It might be worth popping down to the nearest Lego store, they may have it on-site.

Oh Ive got a good one about writing papers. At uni, in pharmacology class, we had to write a few pages on a particular drug - our choice - in pairs. My partner chose MDMA - Ecstasy - which seemed like an interesting choice. We only got half credit because my partner wrote exclusively about how MDMA was fun and we should all try it and drugs should be deregulated. I mean, the regulation of drugs is an interesting topic for discussion, but this was a pharmacology class...

Well I've found love...and Im quiiiite happy....what was the next part? Was it gaming because if so then Im set.

I mean, it'd be weird if this wasnt the case

The state-of-the-art when I was at uni was to create a document in word, with anything in it, maybe copy a wall of text (literally any text) off the internet so the file has some size. Then open the file in raw-code or ASCII format and delete a few random strings and save. Now the file is corrupt and wont open! Mail it in with a nice title and wait for feedback. In theory, this buys you 12-24 hours grace before the professor finds you and was like "I couldnt open your paper" and you'd have it ready and be like "Oh was there a problem? Must have gotten corrupted in transit, Ill mail you a fresh copy!" Cue the university adopting a "zero tolerance" policy so if you didnt electronically submit something that could be read and marked by the very second of the deadline (emailed it in 10seconds late? you missed it sorry you get a zero), thats your problem and if you get a zero because of legitimate computer problems, you get a zero. And as you of course are repeating in your head as I speak - you've got all week, dont submit it at the last minute!! Oh the sweet sting of young person problems!

I did a little reading on this and I think the bottom line is the "limit" is a bit higher than I thought, but only sort of. Bullet speed is indeed limited by the detonation velocity of the propellant and by the speed of sound in the resultant gases, but these maximum values can be in the Mach 10-20 range. However it is a case of severely diminishing returns. It is quite complex because it involves propellant density and overall mass, projectile mass and dimensions, breech and barrel geometry and shaping. What it boils down to is that the "limit" is Mach 3-4, for a reasonable breech pressure and mass of propellant. The theoretical absolute-maximum limit is somewhere near the detonation velocity of the propellant. The theoretical absolute-maximum limit is physically impossible to achieve in practice and it requires an excess of energy to approach it. Kinetic tank cannon achieve velocities in the Mach 5 range using very large propellant/projectile mass ratios by way of a sub-calibre sabot thingy. The HARP gun achieved Mach 6+ by using an UNHOLY amount of propellant in a similar manner and a very long barrel. It should be noted that a breech cannot be made infinitely strong by adding more and more material. Beyond a certain point, a high enough pressure will crack the interior walls no matter how thick and strong the casing. And once its cracked, further shots would be....ill advised. "But p1t1o? With a detonation velocity on the order of Mach10+, cant we achieve higher muzzle velocities than merely Mach6?" Sure, if the barrel is 100% frictionless and the projectile has zero mass. Its also worth remembering that the energy from the propellant combustion has to accelerate not just the mass of the projectile but the mass of the propellant as well. So if you have 3 times the mass of your projectile, of propellant, a full three-quarters of the energy has to go to accelerating the gas rather than your projectile. That is one of the things that leads to diminishing returns when it comes to adding more propellant. So to conclude - There is a maximum limit to the speed of conventionally-propelled bullets. There is also a practical limit, which is a somewhat lower - overcoming this limit requires a large excess of engineering and energy. You cannot increase the range of a weapon (beyond some modest limit) by increasing barrel length alone - the weapon has to be designed as a complete system, the properties of the breech, barrel, bullet, propellant etc all have to work together to achieve an optimum result. Not to mention that other things that affect how the weapon performs, such as weapon harmonics - how the weapon (especially the barrel) flexes and vibrates on firing. Sorry for wall of text, I just wanted to draw a line under all that

The ammunition struggles of the minigunman: "IM HERE MOTHALUVVAS TIME FOR SOME REVENGE AWWWW YEAH LETS GET THIS REVENGE PARTY STARTED!!!" BRRRT .... .... ....

I have heard anecdotally from an RAF pilot that you are never supposed to hear the 3rd "eject", because if you havn't pulled the handle after the 2nd "eject", the person giving the command will have.

Rocket-boosting the projectile is cheating ***EDIT*** I looked up some paperwork on this and apparently the early Martlet-2 was not rocket boosted (until Martel 2G1 - pictured above, 2nd from bottom) and achieved the specs you mentioned. I also looked up the propellant used, and it turned out to be fairly standard, mostly nitroglycerine and nitrocellulose, basically cordite, similar to most firearms even today. What I said about mach limits is still definitely true, Im going to have a wee look and see if I cant find out how the HARP gun was able to achieve such high muzzle velocities. Maybe Im off on the range of where the upper limit lies, but I didnt think I could be that far off. It did use eye-opening quantities of propellant (650-850lbs), but then the projectile weighed 400lbs. I might come back on this. PS: Since Im very cynical, and since the HARP project was the brainchild of one Gerald Bull, I cant dismiss the possibility that the results were falsified. Part of me is protecting my ego, I know, but there you are. https://en.wikipedia.org/wiki/Gerald_Bull Though I think the most likely explanation is that the rules can be broken if you use a large excess of energy, or perhaps the pressure was so unusually high in this device, that the local speed of sound was much higher than in conventional firearms. *********** None of these suggestion require a 50-70m long barrel, and sniper-like accuracy at 11km is probably impossible regardless, without active guidance.

Excellent point! How would we go about discovering whether or not this is true? (that we are functioning as neurons in a larger uber-mind) How can a neuron discover the nature of the mind it is a part of? Is it like matrix-style universe simulations, the existence of which are by definition impossible to prove/disprove from within?

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@everyone but particularly @ARS On barrel length: There is a maximum speed that you can propel a round via gas pressure. It is limited by the speed of sound in the medium - not in air, but in the combustion gases. You cant push the round faster than the gases want to expand naturally. Note that a pile of 100tons of propellant does not produce a shockwave that goes any faster than that from 100pounds of propellant. With explosive propellants this tops out around Mach 3-4. To fire projectiles faster you have to use propellants with much higher sound velocity, so you use a "light gas gun" which uses explosive to compress hydrogen, this hydrogen can then be used to propel projectiles up to around Mach 20-25, commonly used in hypervelocity or high pressure physics research. To fire rounds further, you fire a heavier round. So, the gun with a 50-70m barrel that can snipe out to 11km is total BS. I mean, a 20mm round might be able to travel 11km, but not out of a 50m barrel, and not particularly accurately. I would imagine that due to, amongst other things, air not being a smooth field (pressure variations, wind, turbulence etc.) that theres an upper limit to accuracy that can be achieved with unguided projectiles. You cant just keep arbitrarily scaling up weapon parameters infinitely.

What if humans are unaware of their true roles neuron-analogues in a gigantic super-conciousness and memes are its thoughts?

Sure they do. One nuke per debris object. Everything is vapour. Problem solved. This may be tongue in cheek.

I've never heard of *motion* being part of the whole "spooky action" thing, but this sort of thing is approaching the edge of my knowledge. With standard quantum entanglement, IIRC, the spooky action does take place at the same time (ie: "superluminal") but it is not possible to transmit information in this way. Or something. The XKCD science forum is a good place for stuff like this, there's some folk there that are super into quantum stuff.

What? You only need to boost a mere 38 trillion tons of nitrogen to fill space out to GSO with 1e-7atm of nitrogen. "Impractical"...Pshaw!

Lets be honest. None of these things are going to work because there are too many objects, and thats not even counting things like debris or shrapnel. The only way to solve it properly is if we all agree to not use space at all for a few years, then we nuke the feaces out of the whole zone. Just literally go to town. Keep going until the statistical probability that there is anything significant left in orbit asymptotes to zero. Then we can go back to space....but carefully this time. ***** But seriously, here's an idea. We start launching large tanks of something like nitrogen in retrograde orbits and we just release it as gas. Done often enough it will raise drag in large regions for object in prograde orbits, slowly deorbiting them over time. This would also deorbit fragments and shrapnel, paint chips and the like. Still-active satellites could be re-boosted, I'd wager there are a lot fewer active satellites than there are junk objects, especially if you count debris/shrapnel etc. Im just spitballin' I havnt thought this all the way through, obviously.

Half-butted political discourse is, for good reason, against forum guidelines. I dont want to derail this thread by explaining immigration, european scientific policy, and greater societal concepts such as "you cant just pick the thing you dont like (immigrants) and say that it takes money directly from the thing you do like (space) because thats not how any of that works." so I'll just point out that threads tend to get locked when those subjects take over, which they are wont to do.