Alt text:
While it seemed like a fun prank at the time, I realize my prank fire extinguishers full of leaded gasoline were a mistake.
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All chemical propulsion is just controlled explosions that we use to push a thing forward. It’s not that different, as long as you don’t use it in the atmosphere or near humans.
Yeah I know, it’s the same principle behind modern fuel engines. Still, using nukes for propelling something forward is a bit of a stretch.
Not just nukes, but nuclear shaped charges, at a rate of maybe one per second for a manned vehicle or even more for a faster cargo only mission.
If you can trust the human monkeys with the “shaping” of a rock that got us here, how you gonna distrust the widdle trivial matter of taking little bits of something and splitting them.
It’s shaped charges, it’s totally fine and sane. I’d happily get on the 1,000th Orion flight*.
*Only if that’s a fresh hull
Ah the 50s, when everything atomic was rad.
::Fallout theme starts playing::
“I don’t want to set the world on fire…”
It’s not uncommon in scifi. Netflix’s Three Body Problem also explores such a solution in quite some depth.
I love The Three Body Problem, both the books and the show. But it bothered me to no end to read Netflix’s Three Body Problem.
I’m not familiar with the books, and the plot summary of their Wikipedia article does not mention nuclear propulsion whereas the article for the series does, so I went with that.
Unless what bothers you is the x followed by the apostrophe and the s, which I never know when to omit the s, so it is what it is.
Ah gotcha. Yeah you should check out the books if you’re liking the show! The books go into a ton more detail and the Staircase Project is pretty cool. Seeing it on the screen is cool too, but if you really wanna nerd out I highly recommend the books.
It would probably work just fine, but it needs a huge ship. It could get up to a few percent of the speed of light.
FWIW, nuclear test ban treaties are considered to outlaw it. I think we’re more likely to solve the technical difficulties of antimatter propulsion than we are to get over the political difficulties of nuclear bomb propulsion.
It could get up to a few percent of the speed of light.
So could a person sticking their head out and blowing, but it’s still a terrible idea.
Just as an observation, there was a time when everyone on the Internet was gaga over the idea of Project Orion, and you didn’t dare speak out against it lest you get a hail of downvotes.
It’d work fine in deep space. It’s not a good idea to launch from Earth this way. But again, we’ll probably find something better once we’re at the stage of needing it.
But then how would you launch nukes on orbit without the risk of accudental nuclear explosion?
Implosion-type nukes are all but impossible to make go off that way. They need a whole bunch of small explosives to go off very precisely to squeeze the core in just the right way. A short circuit or a crash won’t have the necessary precision. This isn’t entirely safe, either–it can still cause a small explosion with a flash of fallout and radiation–but it’s a manageable problem.
Gun-types (Little Boy was one) are easier to go off on accident, but the US retired its last gun-type design decades ago. I don’t think Russia used them much, either. They’re only good for smaller bombs, and their safety issues make them questionable for any use. Smaller nuclear powers aren’t bothering with them.
Read “Footfall” for a hard scifi story featuring such a ship.
Will do! Thanks
I like Footfall, but it’s also a little over the top for me.
Co-written by the guy who tried to sell the US military the concept of “rods from god” (orbital kinetic weapon). I wouldn’t expect anything less.
Not worse than a fusion torch. Or open-cycle nuclear propulsion. Or an antimatter drive.
You know, the Kzinti lesson😉
Never heard of those, but if they are on par with project Orion I have some nice readings to do today.
If you’re into hard sci-fi and you’re looking for a good read, they actually dropped a pretty good recommendation with that reference at the end - Larry Niven does a great job of blending real-world theories like Dyson spheres and advanced propulsion drives, with some of the more far-flung standards of the genre like an intra-planetary teleportation grid.
Aren’t there plans again?
Considering that you need huge shields and dampening and you only have the mass of the bomb itself as propelant, is it still as effective as controlled propulsion?
I think you may be mixing up Project Orion (let’s chuck bombs out of the back to make us go zoom) with NERVA (a nuclear thermal rocket engine where the heat from chemical reactions is replaced with heat from a nuclear reactor to generate gas expansion out of a nozzle). Something like NERVA is actually a great idea. Let me tell you why!
-
It’s completely clean (unlike Orion and fission-fragment rockets)
- the reactor and fuel never touch, the fuel goes through a heat exchanger and is not radioactive
-
it provides extremely high efficiency
- chemical rockets top out at ~400-500 isp in vacuum
- NERVA tests in 1978 gave a vacuum isp of 841
- ion thrusters like NEXT has an isp of 4170
-
it provides lots of thrust
- NERVA had 246kN of thrust
- NEXT (which was used on the DART mission) is 237 millinewtons
- That’s 6 orders of magnitude more thrust!
-
No oxidizer is needed
- All you need is reaction mass, just like ion thrusters
For automated probes, the extreme efficiency and low thrust of ion thrusters makes perfect sense. If we ever want to send squishy humans further afield, we need something with more thrust so we can have shorter transit times (radiation is a bastard). Musk is supposedly going to Mars with Starship, and the Raptor engine is a marvel of engineering. I don’t like the man and I’m not confident that he’ll actually follow through with his plan, but the engineers at SpaceX are doing some crazy shit that might make it happen.
Just think though, if the engine was literally twice as efficient and they didn’t need to lug around a tank of oxidizer, how much time could they shave off their transit? How much more could they send to Mars? Plus, they could potentially reduce the number of big-ass rockets they have to launch from Earth to refuel. If you can ISRU methane, then I imagine you could probably get hydrogen.
There are problems that still need to be resolved (the first that comes to mind is how to deal with cryogenic hydrogen boiling off), but like, the US had a nuclear thermal engine in the 70s. It was approved for use in space, but congress cut funding after the space race concluded so it never flew.
I’m happy to see that NASA is once again researching nuclear thermal rockets. Maybe we’ll get somewhere this time.
I’m more with VASIMIR though, maybe with a nuclear reactor for power, since it’s variable.
-
Don’t forget the mass of whatever ablates from your shield!
They spoke to that and found it manageable. The ablation isn’t there deal breaker
So soup sounds like an idea and is actually an idea. Checks out.
I dont know, soup has always been a better idea than it first seemed to me
Depends on the soup I find.
At least when you make soup yourself it good
Canned french onion soup? meh.
Homemade french onion soup? Yeah!
YMMV. For me soup sounds like a good idea but I find it annoying to eat so for me personally it is a bad idea.
What is this transition lense slander
I know right, I recently replaced my glasses with transition lenses and it’s pretty nice.
Who doesn’t want automated sunglasses? Not seeing any downsides yet. Only thing I know they don’t work in cars, but I don’t generally drive so it’s ok
The technology has come a long way since the 90s
I find that they don’t “un-tint” when going inside fast enough for my liking, personally.
Creates kind of the opposite effect of going from a dim room into a bright space. Instead of evrything seeming extra bright, it just dimmed everything and made it more difficult to see.
One problem my mom did not anticipate was that she would be stuck effectively wearing sunglasses for my brother’s outdoor wedding, where was sitting up with the bride and groom for the whole thing (Indian wedding). She just looked like an asshole, and continues to look like an asshole in the just about every photo of the ceremony. Oops.
Why would wearing sunglasses outdoors make someone look like an asshole?
Haha. Good point. You pretty much always have sunglasses on outside like it or not. Even when its shady
In the cold they take too long to transition to clear. So you end up taking them off for a few seconds when you go inside. It’s only minorly annoying.
To be fair, regular glasses mist up anyway when going inside from the cold, so you take them off anyway
Didn’t really notice much in the winter here
Can confirm, it’s all positives with the only downside being that it costs a little more.
They have different varieties, some do work in the car
But then they would probably work in a well lit office too.
No, they don’t change inside (I’ve had them). They do have a slight tint all the time though, which isn’t a big deal.
Was it long ago? Mine have no tint
The human brain is very good at smoothing over brightness differences, even an oppressively well lit office is still typically an order of magnitude dimmer than the sun.
I was under the impression that bloodletting could in some cases actually be beneficial.
Yeah, for people with hemochromatosis (too much iron in the blood) the main treatment is still bloodletting.
Or go piss off Magneto
Yeah, it’s still practiced. But the whole four humors thing is a bit old hat.
I think there’s a few of these misplaced. Heelys>transition lens.
And also often in such cases, blood donation is suggested instead.
Heelys>transition lens.
I dunno, seems kinda unrelated…
Also leeches are used to help veins heal after reattaching fingers/ears/other dangly bits, which is a form of bloodletting
Yeah it can reduce PFAS levels in your system. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2790905
Though better to just donate that blood than let it go to waste.
Didn’t Paul McCartney write a song about blood letting?
🎵if this ever-changing world in which we’re living makes you give in to need… Live and let bleed!🎵
Excuse me, what about pizza in squares?
I guess because there is no crust to grab. Gotta get grease and maybe sauce on your hands to eat the inner squares.
But square pizza is the sort you eat with fork and knive tho?
Not necesarilly. I fear we have to face it: This is one of the rare cases where xkcd fucked it up.
Not at all, they are probably talking about horrible Dayton Style pizza. For when you want pizza but it needs to be thin, unsatisfying, greasy, and difficult to eat.
https://en.wikipedia.org/wiki/Dayton-style_pizza
Fucking heathens, if it weren’t for them keeping keeping the alien technology from area 51 at Wright Patterson AFB I’d have them wiped off the map.
This is the superior thin crust style of pizza. Cut in squares, which is a totally fine and legitimate thing to do.
Do people actually eat this?
https://upload.wikimedia.org/wikipedia/commons/0/04/Marion%27s_Supreme.JPG
I only had New York style pizza in the US and thought the US pizza game isn’t that bad.
People who eat Dayton-style pizza are like the city of Dayton itself—smelly inside and bereft of true purpose. Those of us in the US who haven’t been so psychically damaged wouldn’t eat that shit.
(I’m only just learning about the disgusting gutter pizza. I don’t like Dayton because my last company was slowly destroyed over several years by a company that was headquartered in Dayton. I associate the city with the asshole who was CEO. Fuck you, Chris! I’ve heard Dayton is, at worst, not great, so take my comment as the joke it is.)
Hard to believe but they do. Note the blackened edges to make it even worse. It isn’t a nice char like you get with Neapolitan, or even the seared cheese you get with a good Detroit or Pan, it’s just burnt.
There are many American pizzas that are great, Chicago deep dish, NY, Detroit, on and on, Dayton style is not one of them.
Yes, and well-made crust like this is delicious.
Unfortunately lots of it isn’t great
There is no pizza acceptable to eat with fork and knife.
<Chicago pizza has entered the chat>
That’s a misnamed quiche.
Tomato soup in a bread bowl, with cheese. Not quiche, the filling isn’t egg-based.
It’s delicious. And since the Italians call just about any round bread with toppings pizza (e.g. Bartolomeo Scappi’s pizza was cake with powdered sugar & saffron toppings) it’s pizza. As is New England clam chowder in a bread bowl!
Pizza with zucchini and champignons. Vegetables pizza in short.
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As a fork-and-knife pizza eater, I have come around to pizza squares.
That said, PIZZA BELONGS IN A TRIANGLE
This can be solved by using a napkin
(Or just not caring about the problem anyhow)
Or by cutting it into standard slices. But yeah napkins and apathy work too.
If the pizza is a square or rectangle (like Detroit deep dish or a flatbread) it is on, but round pizza cut in squares is just bad
The only correct way to cut (not too gigantic) round pizza is into six parts so you get equilateral triangles (well, modulo a curved section) which is ideal for holding.
Home-made pizza rarely if ever is round, though, in which you probably don’t want to go for squares but eyeball some appropriately-sized rectangles.
I think sliced bread is overrated as fuck. It used to be nice back when people couldn’t just buy knives for cheap, but nowadays it just means getting stale bread faster.
For some types of bread, the machine can do it much more uniformly and without crushing. This can be difficult for humans.
You can buy your own bread slicer
My appartment is too small for this kind of stuft. Buying sliced bread is fine.
Of course
i got a like 30 year old electric bread slicer, never sharpened the blade, still cuts like brand new, sometimes the crust gets stuck when its a super fresh super crispy crusted bread, but its amazing.
Thanks, i laughed. ^^
Those aren’t good types of bread, though.
I recommend a very nice bread knife! I have a mediocre bread knife that was like 15USD like 15 years ago and it still saws solid slices of soft bread without schmushing the bread!
I’m mostly just commenting on why it was such a big deal in the time that it happened rather than today. Today, we do have more machines, easier access to knives, and generally less domestic work to do than was the case in this era. I do own a breadknife, though I rarely eat bread and it’s mostly denser loaves when I do (a kind of sandwich bread the wife prefers or something like Baurenbrot for my tastes).
But sliced bread has become something else that doesn’t exist with loaves. You can’t buy an unsliced loaf of ultra-processed white bread.
You can get a wide variety of both sliced and unsliced loaves in pretty much every supermarket in my area. The ultra-processed american type bread is something else entirely and it’s also a bad idea too, like pretty much all ultra-processed foods. Can that stuff even get stale? I remember it staying exactly the same up until it grows mold.
For pan loaves, people store it in a plastic bag to keep the crust soft.
Pan loaves should be presliced, stone baked loaves with thick crust should not.
oh lord that alt text
What’s wrong with Transitions lenses. I like mine
Transitions are game changing. Sounds like someone who doesn’t wear glasses all the time. I even had transition sunglasses before I needed glasses - got tired of taking them off going in/out all day.
Not sure who created this (I kkow, XKCD), but it’s mediocre.
Double-ended extension cords belongs in the top
leftright corner. Sounds bad and is bad.Double-ended extension cords belongs in the top left right corner. Sounds bad and is bad.
Remember, you’re probably more technical than the average person. Double ended extension chords sound fine if you haven’t heard of them before until you think about it for five seconds.
I’ve worn glasses my entire adult life and I had to get rid of them because being half blind every time I transition from outside to inside was interfering with my job.
This. I worked in a hardware store as a floater (I’m good at things, they ask me to do random) and often found myself irritated at how often I need to go outside for a minute to meet a customer or something, and then come back in and all the fucking lights are off.
It might just be a joke. I use transitions in my cycling glasses, where I might be in shade or when it starts to get dark (but I’ll still have something protecting my eyes). I use regular sunglasses in the car, as transitions generally won’t work there.
You can get them to work in the car. You just need to break all your windows.
Easy.
I prefer to cut the top off.
My only gripe with them is that if I spend any amount of time outdoors, even if it’s not actually sunny, my glasses quickly turn to shades.
Coming inside and not being able to see a lot.
I specifically got rid of them having had them in my last pair. Too annoying!
They transition very quickly though. Takes like a minute
I work from home in an office garden. The walk from the house to house to the office was enough to transition the lenses and then you’re wearing sunglasses for 5 mins and they slowly change back. Definitely takes longer than 1 minute.
Interesting, yeah, I don’t mind them as much I guess. Now I’m considering just getting prescription sunglasses to wear all the time
Every single glasses of mine have had transition lenses, I can’t imagine my life without them anymore.
I love transitions lenses. I have transitions contacts and they are fantastic.
Omg, does that mean your “eye color” changes in the sun?
If you keep one eye closed and expose the other to sunlight, you can see the difference. The lenses tint a dark shade of purple. I have dark brown eyes, so you can’t really notice the difference easily. There is a purple ring that is most noticeable outside of the limbal ring. They don’t turn your eyes black like you had the tint of sunglasses or transitions glasses, which would be cool.
I would imagine someone with lighter color eyes, like really light blue, would have a very noticeable difference.
Something I did notice as the wearer is when the lenses are tinted there is like a contrast filter on your vision so colors look better.
Holy cow-had no idea they made those.
They kind of released under the radar because a comedy skit about them came out and gaslighted people into believing they were not a real thing.
I only found them because I went to order contacts and saw the product category.
They aren’t as good as sunglasses(but are really awesome) and they don’t work much in the car so you will still want sunglasses.
Same. Although mine became a lot less useful after becoming a night owl.
Replying to spammers sound like a good idea at first, should be top left.
Pizza is way too right and too high on this graph.
One of the cooler parts of Three Body Problem was when they attempted the Orion Project to accelerate a probe to 1% of light speed.
Project Orion is a bad idea??
Just don’t start the nuclear propulsion until you’re outside of earths gravity well…
Project Orion is a bad idea??
A tricky bit of math to achieve, certainly.
I don’t get the diverging diamond interchanges one
Diverging diamond interchanges are a type of road intersection that appears very chaotic from the outside, but are actually pretty simple and safe to navigate
Diverging diamonds are great if your only consideration is car throughput.
If you are considering people walking or riding bicycles, they are shit.
It doesn’t help that US diverging diamonds seem to insist on having pedestrians walk through the median.
But honestly all interchanges are varying degrees of horrible and if you want your city to be bearable to navigate as a pedestrian/cyclist you just really don’t want to do urban highways, or roads above a certain size in general.
I hadn’t considered that. I was still pretty car-brained when i watched the cgp grey video on them, but now that you mention it, i definitely agree
This is expensive to address because you have to separate cyclists out to the right before the right car lane splits for right turns before the crossover. And then you have to build a bridge or tunnel for cyclists and pedestrians. On each side.
Really, any road busy enough to justify a diverging diamond probably already needed separated bike lanes. But in America (motto: “If you aren’t in a car, you don’t matter”), there almost certainly was not any cycling infrastructure there before.
There is one of these near me. Their solution for pedestrians is to make them cross the high speed outer lanes four times (where drivers are encouraged to not slow down). Their solution for cyclists is take the lane and pray or get off and do what the pedestrians have to do.
Edited for clarity: pedestrians cross four times, not drivers are encouraged to not slow down four times.
where drivers are encouraged to not slow down FOUR times
Wtf, thats insane
To be clear, it is four times that pedestrians have to cross, not four times that drivers are encouraged to not slow down. Drivers are not explicitly encouraged to not slow down, but the point of the diverging diamond is to make drivers not have to slow down.
Ohhh, thanks for the clarification 😅
Significantly safer to navigate in practice than traditional intersections, and very straightforward to navigate, if not quite as easy as a normal intersection you’ve seen all your life.
Having to stop for a stoplight twice just to go straight? No thx.
There are many of these where I live. The lights are usually timed so that you just go straight through without having to stop. They’re much better than the traditional intersections that came before.
I will absolutely concede that they’re shitty for pedestrians or cyclists, however.
The ones I’ve used time the pedestrian lights with the traffic, so it’s safer for them. Still tricky for peds going across turn lanes.
They’re usually built over a motorway where there was already two stoplights just to go straight, so …
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