[Waragainstsleep]

Originally Posted by subego 

Let's say you want to spin your space ring to get 1G.

What's the minimum ring diameter for this to be effective?

Effective at what?

[P]

I guess minimum diameter so it doesn't get distracting. Some googling again shows that noone knows. We don't know what rotation speed would be acceptable. Werner von Braun apparently proposed one with a 250 feet diameter wheel and a revolution of 3rpm, which would give about one third gravity, but then others think that 3rpm is too quick and we should keep it down to 1rpm.

[ghporter]

You can get 1G at the outside of any spinning ring. The more important questions than diameter are about angular velocity (or RPM) and how much working height above the deck you would require having some reasonable fraction of 1G.

According to this site's calculations,, a 100m radius ring would produce about 1G if rotating at 3 RPM, while a ring of 50m radius turning at 4.3 RPM would also give about 1G. In both cases, there would be about 0.9G felt at 3m above the theoretical deck.

If you go down to a 20m radius, 7 RPM gives you a bit over 1G at the deck, but you still have over 0.9G at 3m above the deck. Much smaller, and you wind up with some problems: with a 10m radius ring turning at 9.5 RPM, you get about 1G at the deck, but at 3m "above" that, you only have 0.7G, which is enough to (literally) screw with your head - your semicircular canals and vestibular labyrinths to be specific. That could make it hard to maintain balance or coordinate movements between feet and hands.

If you just had to have 1G at the deck, the smallest radius I'd recommend would be 18m at 7.1 RPM, with a maximum working height of 2m above the deck (which is a pretty low ceiling). 20m at 7 RPM would give you more flexibility.

Of course the mechanics of turning a big ring are tricky too. In a practical application of this, I think it would have to be a balance of how hard it is to keep your ring turning at the required rotational speed and how hard it would be to build the size ring needed to satisfy the 1G requirement.

[el chupacabra]

How would that work? Centrifugal force would push you down, but also backwards. It would be like tying a string to a plate, standing an action figure on the plate then twirling/spinning it and expecting the action figure to stand on the plate while not falling off.

[P]

Force would be "backwards" compared to some point in space, not compared to the station itself - and you wouldn't have Earth's gravity to contend with, as you are in freefall compared to that. No, the idea works, the issues are managing to build it in orbit (or L1 or something).

[mindwaves]

Interesting answers. I've never tried apples with cheese before and I'm kind of afraid to do so, haha.

[Laminar]

Originally Posted by el chupacabra 

How would that work? Centrifugal force would push you down, but also backwards. It would be like tying a string to a plate, standing an action figure on the plate then twirling/spinning it and expecting the action figure to stand on the plate while not falling off.

You would only feel any acceleration. Grab a bucket, fill it with water. Swing it in a circle at a steady speed. The water stays in the bucket. Speed up or slow down too quickly, though, and the water comes out.

[subego]

Originally Posted by mindwaves 

Interesting answers. I've never tried apples with cheese before and I'm kind of afraid to do so, haha.

Apple and cheddar omelettes are the bomb-diggity.

[subego]

Thank you everyone for the space station answers!

I guess the follow-up question is do you even notice the gravity is artificial in the 20m radius at 7RPM model? How would it's non-earth qualities manifest?

All you have to do is throw something (a ball) while inside it and it'll appear to curve in a weird direction because you keep spinning while the ball is really still going straight, until it hits a wall.

[el chupacabra]

I still dont understand the space ring thing. Whats to stop me from just floating happily in place while the ring spins around / without me. It seems I wouldnt experience centripetal force until the wall hit me, which would then pull me outward on the ring, wouldn't the wall have to be constantly pushing against me to create the artificial gravity? In other words the wall would have to be inconveniently there to sort of act like the string in the swinging bucket of water?

[subego]

Once you've been pushed to the outside of the ring, the rotational force is pushing you into the "floor", and you don't need the wall anymore. Friction makes you "stick" to the floor, and as long as you're stuck to the floor, you keep rotating with the station, which keeps pushing you down.

The "wall" would be a ladder. Hold on as you go "down" from the (zero-g) center to the floor, and you pick up the ring's rotational forces along the way.

[subego]

It wouldn't behave exactly like normal gravity, though.

If you're standing on the floor, and drop a ball, from your perspective it wouldn't fall straight down. It would hook opposite the direction the ring is spinning. How far would depend on your RPM.

Likewise, if you jumped straight up, you wouldn't land in the same spot. However, you wouldn't just float because even though losing contact with the floor means the the ring is no longer accelerating you, you maintain the same velocity you had the moment you broke contact.

This velocity is tangent to the ring, so it sends you back to the floor sideways.

[subego]

If you drop the ball, it would go in the direction of the arrow...



The thing to note is that's still towards the floor, because the floor curves around, it's just not the same point of floor you dropped it over.

Also note the floor is moving, so it will be catching up. It won't look like it shot off at a right angle to you, because your entire frame of reference is rotating around the ball as it "drops".

[ghporter]

Originally Posted by subego 

Thank you everyone for the space station answers!

I guess the follow-up question is do you even notice the gravity is artificial in the 20m radius at 7RPM model? How would it's non-earth qualities manifest?

Aside from the oddities like what And.Reg posted, there will be enough differential between how things behave at your eye level and how they behave at the floor for you to notice. Along with the curved floor, that's enough to "notice" any time you look.

Note the space station sequence in 2001, and compare it to the sequences aboard Discovery. Even in the massive space station the curve of the floor was easily noticeable, while on Discovery it was almost claustrophobic. The Discovery's centrifuge was 5.5m in radius (around 18 feet), which allows us to get a visual sense of the size of what we've been discussing.

[mindwaves]

Is the adverb dying?

I have been hearing "It's real good" instead of "It's really good" for quite some time. Today at Sam's Club, I saw a sticker on a loaf of bread that says "Fresh Baked" and a Foster Farm's chicken sticker that says "Thin Sliced."

[P]

Think Different?

[ghporter]

The adverb isn't dying. Proper use of English is being vandalized.

Think Different isn't an abuse of adverbs because it's a slogan, and slogans don't necessarily have to be in proper English. But product descriptors should be in proper English. What does "thin sliced" mean when applied to cold cuts? It implies "thinly" sliced, but since the statement isn't in proper English, that's not clear. Maybe the meat was sliced by a guy named Thin...

[P]

Maybe that guy Thin is what got sliced?

[ghporter]

Ewwww. I hope he didn't get any of himself on the cold cuts!

[subego]

Thin coldly cuts.

[Gearhead40]

What happens if your spouse changes into a person that you never wanted to marry in the first place?

[andi*pandi]

What kind of changes? Have you changed also?

[Cap'n Tightpants]

Originally Posted by Gearhead40 

What happens if your spouse changes into a person that you never wanted to marry in the first place?

It's rare for a couple to be together for life (some would even say it's unnatural), and fighting to stay together often isn't the right thing to do.

[el chupacabra]

Why is it, as computer hardware advances, programs/apps seem to get larger and more bloated as if to make sure to compensate while accomplishing the same menial task? Many tablet/phone "Apps" remind me of early 90's mac games or "programs", only difference is 90's programs took 2-4MB of space while modern apps take up 20-100.

[P]

What Andy giveth, Bill taketh away. If you want an even more absurd comparison, try games. The Legend of Zelda, a game that must have spent months playing, is 64 KB. A modern game of similar scope is probably only limited by a dual-layer Bluray, that is 50 GB. That is a factor close to a million.

The answer usually given is that back when weak computers were all we had, focus was on making programs work at all on the hardware available. Now that hardware is more powerful, it is more important to develop quickly. Programmers moved from fine-tuned assembly to high-level languages to big general libraries instead of writing purpose-build code, which means that code size increases and speed drops.

In a way, we have moved into the industrial era - instead of a hand-carved cabinet, you get something of glue and sawdust from IKEA. Not as pretty, not as solid over the years, but cheap and efficient to produce.

[Cap'n Tightpants]

That's why when games like the Witcher series, Pillars of Eternity, and the forthcoming Tides of Numenera (oh my!) it's important to play them, if you're into adventure/RPG genre.

(Especially Tides of Numenera, that's going to be a game changer (PI). Though I'd wait until it's out of early access.)

[BLAZE_MkIV]

A big part of game size increase is the pictures. Those tiny little 4 bit sprites in zelda became multi MB images files and texture maps. Then you add in "cinematic" cut scenes for huge increases in storage needs with no software behind them.

[Doc HM]

There a brilliant book called The Backroom Boys

Backroom Boys: The Secret Return of the British Boffin: Amazon.co.uk: Francis Spufford: 9780571214976: Books

4 stories of British boffinism at its best (from Concorde on down), but with a brilliant section on the development of the old arcade style game Elite.

Awesome.

[Laminar]

B...boffin?

[Cap'n Tightpants]

You call yourself a Top Gear fan?

[Laminar]

No?

[Cap'n Tightpants]

that explains it

Originally Posted by P 

What Andy giveth, Bill taketh away. If you want an even more absurd comparison, try games. The Legend of Zelda, a game that must have spent months playing, is 64 KB. A modern game of similar scope is probably only limited by a dual-layer Bluray, that is 50 GB. That is a factor close to a million.

The answer usually given is that back when weak computers were all we had, focus was on making programs work at all on the hardware available. Now that hardware is more powerful, it is more important to develop quickly. Programmers moved from fine-tuned assembly to high-level languages to big general libraries instead of writing purpose-build code, which means that code size increases and speed drops.

In a way, we have moved into the industrial era - instead of a hand-carved cabinet, you get something of glue and sawdust from IKEA. Not as pretty, not as solid over the years, but cheap and efficient to produce.

I was just thinking about this effect the other day. I mean, Super Mario 64, an 8 MB game, was blazing fast and had all throughout well-resolved polygons. The 3D aspect looked real. This was all 20 years ago, and done on a 93.75 MHz CPU with a 62.5 MHz GPU.

[sek929]

Originally Posted by Laminar 

B...boffin?

Tinkerer basically.

[Doc HM]

Originally Posted by sek929 

Tinkerer basically.

A bit more than that perhaps.

[mindwaves]

Couldnt you eat any plant, assuming it wasn't poisonous?

Let's assume that you are stuck on a deserted island surrounded by wild plant life. None of the plants are immediately edible, but if you needed to live for a few days longer, couldn't get you eat whatever plants are available? Your body will not be able to digest a large percentage of it much like a cow, but you can get a few digestive calories from it, right?

That won't last you for a long time, I know, but in order to last a bit longer, could a human do so?

[P]

I guess that that is what you call a high fiber diet.

I expect that it will just go through you, making you feel full but not giving you any nourishment.

[subego]

I feel you'd probably expend more calories foraging, chewing, and trying to digest it then you'd get back. As an aside, it wouldn't happen over a couple days, but your teeth would probably end up falling out it you ate enough grass (silica content).

[Cap'n Tightpants]

wrong thread

[John B. Smith]

How come you can't mix clear and dark liquor drinks without having an atrocious hangover?

[osiris]

Why has Elf been on TV now for the past month? Did Christmas move?

Why were mosquitos created?

[P]

Originally Posted by And.reg 

Why were mosquitos created?

Because there was this huge population of two-legged hairless apes that a species could parasite on.

[Demonhood]

Originally Posted by John B. Smith 

How come you can't mix clear and dark liquor drinks without having an atrocious hangover?

I don't think that matters. From my experience it's quantity and quality (and hydration) that determines how you feel the next day. A lot of crappy drinks call for mixing together the entire contents of your liquor cabinet in the hopes of stumbling upon something tasty. Plus, people mix in low quality vodka or gin just to up the alcohol content of something without changing the taste. This makes the drink significantly more alcoholic than you think it is, getting you drunk before your brain knows what's going on. Or they add a light flavored liquor to a darker drink to sweeten it up. Which makes it go down easier so that you'll drink even more.

[Waragainstsleep]

Originally Posted by P 

Because there was this huge population of two-legged hairless apes that a species could parasite on.

Haven't they been around way longer than us?

[P]

In existence, yes - as a family of species at least - but it is the current population boom that has lead to them being so successful as a species. Remember reading somewhere the percentage of their food that comes from humans these days, and it was a very high number.

[iMOTOR]

As I understand it though, blood is only used by female mosquitos to produce eggs, it's not food per se.

[el chupacabra]

Whats so special about the Mona Lisa painting, it's kind of plain isn't it?
On a similar note why is most Renaissance art focused on religion, isn't there anything else to paint other than bible characters?

[subego]

I think the Mona Lisa is overrated.

I should be able to answer these questions, because I went to art school and all, but I've forgotten a lot of my history.