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A Star in a Bottle

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Re: A Star in a Bottle

#81

Post by nickstinemates »

sitkack wrote: post #79
nickstinemates wrote: post #75

Earlier quoted context omitted.

Not a SMS pricing issue. I believe it's the fact that it costs anything at all. When wifi is free, and you have a method that enables communication without a phone plan.. that's goodness.

Correct, but that is a failure of the carriers not supporting their customers. Cellular carriers should be supporting VOIP over data (3g,4g) and internet wifi. But since they are rent seeking, they won't disrupt their voice and sms traffic, enabling plays like WhatsApp.

No debates there; it will be interesting to see how phone carriers fight being 'dumb pipes', which I believe we all want to see as inevitable.

Re: A Star in a Bottle

#82

Post by InclinedPlane »

ck2 wrote: post #16

LHC didn't make me nervous and I laughed somewhat at the people who sued to keep it off for fear it might end the world. This one however, I dunno. Sounds like things could go wrong with that much energy. When they made the first atomic bomb, they had theories about what might happen but not 100% sure and there were some surprises. But I'll take death from this over death from fracking.

Loss of containment is expected, and is more or less trivial. The result is that the fusion plasma simply expands or runs into the side of the reactor wall. This may sound dramatic but it's not. We're talking about at most a few grams of hot gas/plasma. In reality it's not any more significant than running a welding torch or a plasma cutter. As for the fusion reactions, they require the high pressure and high temperature conditions of containment in order to operate. Once containment breaks down the fusion reactions stop.

Don't let ignorance fuel fear of technological advancement.

Re: A Star in a Bottle

#83

Post by mng2 »

ck2 wrote: post #28

Check this out, Japan is going their own way instead of this experiment According to researchers at a demonstration reactor in Japan, a fusion generator should be feasible in the 2030s and no later than the 2050s. Japan is pursuing its own research program with several operational facilities that are exploring several fusion paths. http://iopscience.iop.org/0029-5515/45/2/004 Also, they are already planning the succe…

Actually, Japan is one of the biggest contributors to ITER. Notably, they are continuing a strong domestic fusion program -- compare this to the U.S., where most of the fusion budget is going to ITER, at the expense of domestic fusion programs (such as Alcator at MIT).

Re: A Star in a Bottle

#84

Post by aqme28 »

Florin_Andrei wrote: post #72
aqme28 wrote: post #18

Earlier quoted context omitted.

It's actually a lot less energy than it sounds like. The temperatures will hit 10-100 times the temperature of the sun, but the density inside will be very very low. This thing couldn't vaporize a car. Remember, this is only a 500 megawatt device, and the reaction is so unstable that if it somehow escapes the containment of the device it dies instantly. It can't "run away" like some fission reactions can. edit: Not a…

> but the density inside will be very very low The density is not that low, but the total amount of ultra-hot matter is pretty small. If magnetic confinement is lost, the plasma will expand and cool; there is no sustained fusion without the confinement. The core would probably be wrecked, but that's about it.

"The density is not that low, but the total amount of ultra-hot matter is pretty small."

I'm sorry but I don't understand the distinction.

Re: A Star in a Bottle

#85

Post by lloeki »

leoedin wrote: post #45
ryanklee wrote: post #15

> will stand a hundred feet tall, and it will weigh twenty-three thousand tons—more than twice the weight of the Eiffel Tower. This is a strange sentence. (1) Notice Height of object-A; (2) Notice Weight of object-A; (3) Compare Weight of object-A to Weight of object-B where object-B is known more for its property of Height than of its Weight. The sense here (I think) is that the Eiffel tower is significantly taller…

The article's full of fairly silly elaborate descriptions. My favourite so far (3 pages in): > Some in the field believe that a working machine would be a monument to human achievement surpassing the pyramids of Giza. Which suggests that the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed. You only need to take a look at almost any 20th century bridge, skyscraper or even ship to kn…

> the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed.

> [...] the last few centuries have completely and utterly surpassed that

In terms of what they were built for, that is travel through time mostly unharmed for several thousands of years, a literal vessel of eternity, this claim is undebatably false. Few things we have built in the last two centuries will survive more than a decade if left unattended, and even fewer more than a century. It takes but a trip to Normandy to see german bunkers getting swallowed by nature. The smarter we get, the less durable we build things: we split atoms, we flick electrons and we land proxy explorers on nearby celestial bodies but our grandeur is a delusion and nothing will remain should our kin be obliterated. The testament of mankind that are such incredible buildings can only be surpassed by moving our butt out of this rock and sustain a decent living on the next one, ensuring our species survival. Any technological achievement is but a bullet point towards that goal.

Re: A Star in a Bottle

#86

Post by dragonwriter »

aqme28 wrote: post #84
Florin_Andrei wrote: post #72

Earlier quoted context omitted.

> but the density inside will be very very low The density is not that low, but the total amount of ultra-hot matter is pretty small. If magnetic confinement is lost, the plasma will expand and cool; there is no sustained fusion without the confinement. The core would probably be wrecked, but that's about it.

"The density is not that low, but the total amount of ultra-hot matter is pretty small." I'm sorry but I don't understand the distinction.

> I'm sorry but I don't understand the distinction.

While its contained, the density is not that low; if it loses containment, the density will become low as it expands. At least, that's my understanding of the distinction here.

Re: A Star in a Bottle

#87

Post by dragonwriter »

lloeki wrote: post #85
leoedin wrote: post #45

Earlier quoted context omitted.

The article's full of fairly silly elaborate descriptions. My favourite so far (3 pages in): > Some in the field believe that a working machine would be a monument to human achievement surpassing the pyramids of Giza. Which suggests that the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed. You only need to take a look at almost any 20th century bridge, skyscraper or even ship to kn…

> the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed. > [...] the last few centuries have completely and utterly surpassed that In terms of what they were built for, that is travel through time mostly unharmed for several thousands of years, a literal vessel of eternity, this claim is undebatably false. Few things we have built in the last two centuries will survive more than a de…

> It takes but a trip to Normandy to see german bunkers getting swallowed by nature.

Or, especially for the SF Bay Area crowd, you could go to the Marin headlands and see US bunkers from the same era -- intended to defend against Japanese attack -- doing the same thing. Shorter trip.

Re: A Star in a Bottle

#88

Post by phest »

leoedin wrote: post #45
ryanklee wrote: post #15

> will stand a hundred feet tall, and it will weigh twenty-three thousand tons—more than twice the weight of the Eiffel Tower. This is a strange sentence. (1) Notice Height of object-A; (2) Notice Weight of object-A; (3) Compare Weight of object-A to Weight of object-B where object-B is known more for its property of Height than of its Weight. The sense here (I think) is that the Eiffel tower is significantly taller…

The article's full of fairly silly elaborate descriptions. My favourite so far (3 pages in): > Some in the field believe that a working machine would be a monument to human achievement surpassing the pyramids of Giza. Which suggests that the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed. You only need to take a look at almost any 20th century bridge, skyscraper or even ship to kn…

You went from "a monument to human achievement surpassing X" to "the first human achievement surpassing X". Fairly silly you said? ;)

Re: A Star in a Bottle

#89

Post by mng2 »

jackgavigan wrote: post #9

As a child, I read Friday by Robert A Heinlein, which portrayed a future in which energy needs are addressed by energy storage devices called "Shipstones", which are described as a way to pack more kilowatt-hours into a smaller space and a smaller mass than any other engineer had ever dreamed of. To call it an "improved storage battery" (as some early accounts did) is like calling an H-bomb an "improved firecracker."…

Laboratory fusion is a rather delicate process, once described as 'containing a blob of jello with rubber bands'. The typical Tokamak fusion plasma is orders of magnitude less dense than air, and if it hits the wall of the containment chamber, it rapidly loses heat and stops fusion-ing. The challenge is really to keep it going long enough and strong enough for it to be useful; there is no runaway mechanism.

Re: A Star in a Bottle

#90

Post by sbierwagen »

jackgavigan wrote: post #9

As a child, I read Friday by Robert A Heinlein, which portrayed a future in which energy needs are addressed by energy storage devices called "Shipstones", which are described as a way to pack more kilowatt-hours into a smaller space and a smaller mass than any other engineer had ever dreamed of. To call it an "improved storage battery" (as some early accounts did) is like calling an H-bomb an "improved firecracker."…

  Also, what happens if the mechanisms that contain the "Star 
  in a Bottle" fail? Will the French Alps suddenly and 
  catastrophically acquire a new valley?
This is a reasonable concern, but your intuitions on the physical processes involved are off by a couple orders of magnitude.

From a previous comment on another fusion story, two years ago: http://news.ycombinator.com/item?id=2839722

  Fusion reactors are fundamentally different from fission 
  reactors. You have to get a tenuous wisp of hydrogen (the 
  reactor in this particular experiment was running at 10 
  mTorr, or 0.0013% atmospheric pressure) very, very hot, and 
  keep it away from solid matter, which is millions of 
  degrees of colder than the fuel plasma, and will suck all 
  of the energy out of the reaction.

  You shut off the containment coils, and tremendously hot 
  plasma ions leap away from each other, instantly stopping 
  the reaction. If the reaction somehow "runs away", which it 
  absolutely can't, then it brushes the walls of the vacuum 
  chamber, poisoning it with cold metal ions, like injecting 
  lead shavings that have been chilled to absolute zero 
  directly into your heart.

  If our magical "runaway reaction" somehow overcomes this, 
  and melts a hole in the vacuum chamber, then the atmosphere 
  rushes in, both freezing cold and at intolerably high 
  pressure, like the North Sea flooding into the hull of a 
  submarine resting on the ocean floor.

  Fusion reactors don't melt down, or explode. At all. It 
  just can't happen, much like how a Yugo rear-ending a 
  garbage truck in Brooklyn doesn't instantly consume all of 
  New York City in a gasoline fireball.
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