A question about Fission and Fusion and energy production.

[Jerromy]

If you ignore the challenges and continue presenting unrealistic ideas time and time again while poo pooing real physics, eventually people's patience will wear thin. Dryson is one such example of this.

As far as the golden rule - if I ever present an idea like some of the ones in this thread, I would hope I would be shot down in flames!

Will you not be humbled and bow before the "concept without understanding" master when he invents "neutrino shockwave" batteries for portable energy storage? Personally I think lithium ion batteries suck and he's using FTL travel as a cover for his true intentions...

 

[kg]

I don't think this idea is wrong, I just get a feeling it would be ALOT less eficient than he thinks it might be. A type ll supernova takes the weight of ten or so solar masses to create the effect he's looking for. I wonder how a supernova would compare with conventional rocket fuel for energy output on a pound for pound basis?

 

[csmyth3025]

I don't think this idea is wrong, I just get a feeling it would be ALOT less eficient than he thinks it might be. A type ll supernova takes the weight of ten or so solar masses to create the effect he's looking for. I wonder how a supernova would compare with conventional rocket fuel for energy output on a pound for pound basis?

If you're looking to get more bang for your buck, nuclear fusion is about as good as it gets. We haven't been able to produce sustained and controllable nuclear fusion yet, but we're slowly inching closer to achieving it at some ground-based experimental facilities.

Dryson's idea is definitely wrong. The sort of reactions that he describes are imagined only by dryson. He wouldn't propose them if he'd just sit down and read some wikipedia articles (or,preferrably, a book) on stellar evolution and/or nucleosynthesis.

Chris

 

[kg]

...If you're looking to get more bang for your buck, nuclear fusion is about as good as it gets. We haven't been able to produce sustained and controllable nuclear fusion yet, but we're slowly inching closer to achieving it at some ground-based experimental facilities. Dryson's idea is definitely wrong. The sort of reactions that he describes are imagined only by dryson. He wouldn't propose them if he'd just sit down and read some wikipedia articles (or,preferrably, a book) on stellar evolution and/or nucleosynthesis.
Chris

Hi Chris,
I had wikipedia in mind...

http://en.wikipedia.org/wiki/Nuclear_fu ... ion_chains
At the temperatures and densities in stellar cores the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm³), the energy release rate is only 276 μW/cm³—about a quarter of the volumetric rate at which a resting human body generates heat.

I was just musing on how inefficent recreating a stelar environment would be as a power source for a spaceship.

 

[csmyth3025]

Hi Chris,
I had wikipedia in mind...

http://en.wikipedia.org/wiki/Nuclear_fu ... ion_chains
At the temperatures and densities in stellar cores the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm³), the energy release rate is only 276 μW/cm³—about a quarter of the volumetric rate at which a resting human body generates heat.

I was just musing on how inefficent recreating a stelar environment would be as a power source for a spaceship.

The quoted figure is somewhat misleading in regard to the possible use of nuclear fusion as a source of power. Nuclear fusion produces about 10 million (10^7) times as much energy per pound of fuel consumed as chemical reactions (ie, burning fossil fuels). A comparison can be found here:http://fusedweb.llnl.gov/CPEP/Chart_Pages/1.EnergyConversion.html

The whole trick is to sustain a rate of fusion that produces sufficient energy for the purpose intended - power production or spaceship propulsion, for example. Current efforts are directed at producing sustained nuclear fusion for the purpose of power production.

Chris