Interesting, wouldn’t the late heavy bombardment have destroyed the planet? I mean, can planets even survive in such a universe?
Sure – planets are massive compared to the typical size of objects remaining close enough to their orbit to impact them. The Moon was formed from material lost from the Earth after an impact with a Mars-sized object, and it’s still here.
As for the motile meat that clings to life upon it, that’s a different story.
When I ask Whyte, who is 54, to compare his level of optimism now to any other point in his career, he says, simply: “It is at the maximum.”
Good strategic answer. Could still mean “very low.”
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Can we call one-celled organisms meat? I don’t think the Earth had multicellular organisms until only 600 million years ago (and I’m not counting stromatolites as meat, either).
On another note, I’ve seen it suggested that life could have survived the late heavy bombardment. (It seems plausible to me but I’m not an expert by any means.)
Similar to a particle accelerator, and a particle accelerator does cause fusion. The problem is that the probability of fusion when two particles collide is very small. In a particle accelerator you pay the energy cost to accelerate the particles, then get one shot for them to cause fusion. You never get enough back. You need many many collisions to get a fusion event. So what you actually need is a very, very hot plasma, where a bunch of high energy protons are banging around continuously colliding. You pay the energy cost to heat them up once, but get many many attempts to get fusion. The problem is that very hot plasmas are hard to contain, and they also cool down rapidly by radiating heat. So you need to confine the plasma at a high enough temperature and pressure for long enough to get more fusion than it cost you to heat it up in the first place.
A lot of people say that it is so hard because it is recreating the conditions at the center of the sun. That isn’t really true – it is much harder. The sun works by being so massive. The average time it takes a hydrogen atom to fuse in the core of the sun is like a billion years. It is a very low density of energy production, but makes up for it by being so massive. Fusion reactors on earth can’t wait billions of years, so they have to ratchet up the temperature and pressure.
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that’s one heck of an asterisk 
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Obviously. Must Jan Hammer that in?
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Also, “Tottenham Hotspur is the club of the future.”
(For non- soccer fans, this line is usually followed by, “…and it always will be.”)
No risk of meltdown : A Fukushima-type nuclear accident is not possible in a tokamak fusion device. It is difficult enough to reach and maintain the precise conditions necessary for fusion—if any disturbance occurs, the plasma cools within seconds and the reaction stops. The quantity of fuel present in the vessel at any one time is enough for a few seconds only and there is no risk of a chain reaction.
ITER is about the biggest proposed reactor design out there, and its website says that an ITER-sized commercial reactor would burn about 250kg of fuel a year, which means it would produce roughly 250kg of helium per year, which I guess is a usable quantity and it could be recovered and used. There are no radioactive isotopes of helium that last more than a second so it could be used safely. For comparison, worldwide helium production (actually recovery) from natural gas operations is in the millions of kg per year so… even if there were 100 ITER-sized plants it wouldn’t change helium economics very much.
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Aren’t we already harnessing fusion power? All renewables are ultimately fusion powered (except for geothermal), only we’ve harnessed nature’s approach to fusion engineering (ie, a big ball of gas 2 x 10 to the 30th kg).
Our fusion-powered future is almost here already.
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Also fossil fuels are fusion power (which was stored in carbon chemical bonds, i.e. oil, coal and gas). Arguably, also fusion power is fission derived, since uranium has been created in fusion events (like every other atom except for hydrogen)
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This is fusion.
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Ah. You beat me to it…
This is my point. It all depends on whether fusion is really clean. D-T fusion creates a neutron and a gamma ray, both with energies over 10 MeV. The fusion plant will have to have some layer of material that absorbs this radiation, and turns it into heat. This will probably produce a lot of radiation products. If you have built your plant of low atomic number materials then you risk geting low atomic number isotopes. As we are creatures that are mostly made of carbon, oxygen, hydrogen, nitrogen, and phosphorus, this is probably a bad thing as these can get into our chemistry.
Is this option worse than putting in a thin layer of depleted uranium? This is a by-product of conventional reactors. It is much better at stopping the radiation, so you need less of it. It will give out more eneregy then the incoming radiation. We know the problems of processing the products, where I don’t think anyone has a solution for disposing of an irradiated tokomak.
It is reasonable to compare fusion and fission, but first we need to downgrade a couple of myths…
An atomic reactor is not a machine where power comes out of one end, and atom bombs drop out the other. You have to process the material, which is often more complicated than making the reactor itself. There are reactor designs that do not produce any raw materials for weapons. Proliferation can be avoided.
Fusion is unlikely to be clean. Nobody liks a downer, but the physics that says it will produce radiation products is pretty basic and seems pretty solid. There may be a solution, but I would want to see it first.
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Life is but bottled sunshine, and Death the silent-footed butler who draws out the cork.
— Wynwood Reade
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First there was a big bang. It was all downhill after that. 
It was done in 2013. Not sure what the current state of play is though.
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Ex-smackly my point! Always 10-15 years out! Alotta people don’t know that Fusion power is also dirty, creating radioactive byproducts in reactor walls, etc. Fundamental problem, earth bound fusion reactors can reach temperature but can’t reach PRESSURE (it’s all about the pressure…stupid!) Inside the Sun. So the smarter-than-physics physicists try to compensate with super high temperatures instead and guess what? It’s been a science experiment for 50 years and will continue to drain Gov’t Science budgets forever until the public gets smart and shuts it all down. If society put this much money into low-cost workable Thorium fission reactors, we’d have unlimited clean nuclear energy by now.
