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Google revives controversial cold-fusion experiments

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Re: Google revives controversial cold-fusion experiments

#141

Post by olooney »

mikejulietbravo wrote: post #34

Is there an ELI5 of why cold fusion is so difficult to achieve?

Because at an atomic level "cold" means "slow" and under the standard model you need to slam protons into each other fast if you want them to fuse.

Here is a true "Explain it like I'm five:"

Kid: I want candy!

Mom: There's candy inside the pinata.

Kid: How do I get it out?

Mom: Hit it with this stick. If you hit it hard enough, the pinata will break and candy will come out.

Kid: gently taps pinata with a stick Mom, it's not working.

Mom: well, you have to hit it hard enough to break it. Try swinging the stick faster.

Kid: But I don't want to swing it fast. I want to swing it slow!

Mom: Then you won't get any candy.

Kid: crying

Cold fusion is based on the belief that there is some way around this fundamental limitation. This would not be based on any of the known laws of physics (the standard model) and would be by definition new physics. If we discount certain discredited experiments which could not be reproduced, then there is no experimental evidence that this ever occurs, nor is there any unexplained phenomena that would require such new physics. Nevertheless, some people feel the search is still worthwhile.

I give a more detailed account (ELI22+) with and physics and numbers above: https://news.ycombinator.com/item?id=20034550

Re: Google revives controversial cold-fusion experiments

#142

Post by jpeg_hero »

olooney wrote: post #121
imglorp wrote: post #101

Earlier quoted context omitted.

This tabletop research is orders of magnitudes cheaper than hot fusion. It's a huge reward for tiny risk.

Ah, yes, the good old Pascal's mugging[1]. I am aware that cold fusion experiments are both much cheaper, and if successful, considerably safer and cheaper than hot fusion. Yet, there is no plausible mechanism for fusion to occur at room temperature. For two protons (hydrogen ions) to fuse, they must be brought to within 10e-15 m of one another. This requires overcoming the Coulomb repulsion between the two positivel…

What about “Bubble Fusion” or some other physical process that you can’t foresee, could that pass 6KeV ? Localized?

Re: Google revives controversial cold-fusion experiments

#143

Post by coolio2657 »

ehsankia wrote: post #140
olooney wrote: post #136

Earlier quoted context omitted.

These two projects look great, and are exactly the kind of projects where I can see Google making an impact. I think it is extremely likely that we will struggle to build working reactors until we have an "AutoCAD for magnetic containment" which is able to accurately simulate real world plasma physics, after which I expect that a working design will be discovered within a few years, and then constructed within a deca…

And that's exactly the kind of stuff Google is trying to accelerate. One tangential but highly relevant example is their work on predicting molecular properties [0]. They were basically able to use neural networks to speed up the simulator by 300,000x, taking something that would take hours to less than a second. As you mention, this entirely changes the way you work and iterate. Here's a video of Jeff Dean talking m…

How can something like this even conceptually make sense? I'm sorry, but can someone explain to me how a neural network could approximate physically-deduced laws of nature (as had-coded into the classical simulator as I imagine) "without any distinguishable error"?

This is the biggest bs I have ever heard, since an molecular physics simulator that is beat by a neural network can only just be unoptimized as hell.

Re: Google revives controversial cold-fusion experiments

#144

Post by ars »

criddell wrote: post #73
ars wrote: post #45

Earlier quoted context omitted.

The simplest answer is: It's not real. There is no such thing as cold fusion. It's not a matter of "so difficult", it's not actually possible. Are you asking, why is there no such thing as cold fusion? If so then in the simplest way I can explain it: Atoms are like little magnets that repel each other. To get fusion you need to get the atoms to touch - but you can't, they repel. So you have to press them together rea…

> Atoms are like little magnets that repel each other. Is that a good analogy? I wonder because the first thought that popped in my head is that magnets also attract each other.

> is that magnets also attract each other.

Electrons attract atomic nuclei (which is the part of the atom that fuses), normally they are too far away to matter, but if you replace them with muons (which are basically heavy electrons) then you can actually help the atoms come close enough because the muon attracts both.

Since the muon is heavier it orbits closer to the nucleus of the atom, which helps it cancel out the repelling force.

It's too bad muons cost too much energy to be useful this way, or we'd already have commercialized fusion.

Re: Google revives controversial cold-fusion experiments

#145

Post by p1mrx »

ErikVandeWater wrote: post #126
paulmd wrote: post #124

Earlier quoted context omitted.

Humanity can already access more energy than is healthy for our planet. Even if you had a zero-greenhouse-gas source of energy, all that energy is eventually dissipated as heat, so it would not be safe to use an unlimited quantity of it. I looked at the numbers about 10 years ago and iirc I concluded that waste heat is about 10% the impact of greenhouse gasses, so not insignificant. I don't remember how I got that nu…

If we had near unlimited energy, we could find a way to trap heat energy and remove it.

Where would the heat go?

Re: Google revives controversial cold-fusion experiments

#146

Post by de_watcher »

p1mrx wrote: post #145
ErikVandeWater wrote: post #126

Earlier quoted context omitted.

If we had near unlimited energy, we could find a way to trap heat energy and remove it.

Where would the heat go?

To the orbital ring, then to its radiators.

Alternatively we can tone down the sun with the shade satellites.

Re: Google revives controversial cold-fusion experiments

#147

Post by neuronexmachina »

coolio2657 wrote: post #143
ehsankia wrote: post #140

Earlier quoted context omitted.

And that's exactly the kind of stuff Google is trying to accelerate. One tangential but highly relevant example is their work on predicting molecular properties [0]. They were basically able to use neural networks to speed up the simulator by 300,000x, taking something that would take hours to less than a second. As you mention, this entirely changes the way you work and iterate. Here's a video of Jeff Dean talking m…

How can something like this even conceptually make sense? I'm sorry, but can someone explain to me how a neural network could approximate physically-deduced laws of nature (as had-coded into the classical simulator as I imagine) "without any distinguishable error"? This is the biggest bs I have ever heard, since an molecular physics simulator that is beat by a neural network can only just be unoptimized as hell.

I think this is an example of something similar: https://www.sciencedaily.com/releases/2019/05/190517145112.h...

> Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth

Re: Google revives controversial cold-fusion experiments

#148

Post by AnthonyMouse »

dTal wrote: post #132
AnthonyMouse wrote: post #98

Earlier quoted context omitted.

It's also assuming they would do something untoward with the monopoly, rather than just building a thousand new power plants and then making ten trillion dollars by being the lowest cost provider of zero carbon power generation for twenty years.

I don't know how the math works out exactly, but it seems not unlikely that the optimal rollout for curbing carbon emissions as rapidly as possible is not the same as the optimal rollout for maximizing value to shareholders.

Why not? If someone is buying power from coal instead of you when you have lower costs, that's money you're leaving on the table.

Re: Google revives controversial cold-fusion experiments

#149

Post by FranciscusG »

olooney wrote: post #121
imglorp wrote: post #101

Earlier quoted context omitted.

This tabletop research is orders of magnitudes cheaper than hot fusion. It's a huge reward for tiny risk.

Ah, yes, the good old Pascal's mugging[1]. I am aware that cold fusion experiments are both much cheaper, and if successful, considerably safer and cheaper than hot fusion. Yet, there is no plausible mechanism for fusion to occur at room temperature. For two protons (hydrogen ions) to fuse, they must be brought to within 10e-15 m of one another. This requires overcoming the Coulomb repulsion between the two positivel…

Coulomb forces are much weaker at the ends of highly elliptical nuclei. We've always assumed atomic nuclei are spherical. They are not. Iron nuclei have ends where the Coulomb forces are two orders of magnitude lesser than assuming a spherical shape would predict.

Re: Google revives controversial cold-fusion experiments

#150

Post by dTal »

AnthonyMouse wrote: post #148
dTal wrote: post #132

Earlier quoted context omitted.

I don't know how the math works out exactly, but it seems not unlikely that the optimal rollout for curbing carbon emissions as rapidly as possible is not the same as the optimal rollout for maximizing value to shareholders.

Why not? If someone is buying power from coal instead of you when you have lower costs, that's money you're leaving on the table.

I'm sure there's lots of ways it could happen. Off the top of my head - you can't just snap your fingers and start selling power, you need to build the reactors, scale out infrastructure, etc etc. There's huge expenditure involved. If you have a giant pile of money in the bank, earning interest, it might not be worth your while to spend it on that.

Another point - how much do you charge for the power? If your goal is to get people to switch, the answer is "as little as you can". If your goal is to make money, the answer is "as much as you can".

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