this post was submitted on 21 Jan 2025
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I'm studying Physics at the moment and Prof. gave us a printout of a textbook last week stating that the internal of the sun generates approximately 150 W / m³ on average. That's about as much as a compost pile, so, not very much. The sun only generates enormous amounts of power because it's so huge. In other words, reproducing fusion on Earth might actually not be very efficient.
Different kind of fusion. Don't forget hydrogen bombs have been around for decades, right? They're just not very controlled and harnessable.
To the sun's credit, it's 4.5 billion years in and it's still got plenty of juice left to go.
Look up the etymology of the word "sophomore".
Yeah that is not how that works
The sun is enormous, yeah, but fusion only really happens at the core. A very tiny fraction of the sun is doing the fusion, the rest jlgets heated up, makes gravity and such, bit doesn't really do anything of interest energy wise.
Fusion creates a shit tonne more energy than 150w/cm3. Heck, you've never seen what a nuke does
No, OP is right - or rather, OP's physics professor. There's different kinds of fusion, though, and nobody's suggesting we do the exact same kind here on Earth (we basically can't).
That's power density (Watts). Multiply by 10 billion years to get energy density.
Found this article
https://www.abc.net.au/science/articles/2012/04/17/3478276.htm
And it looks like it's saying that the energy produced by nuclear fusion (which happens in the relatively small core) divided by the entire mass of the sun, gives you that low number.
Terrestrial fusion power plants are aiming to be sun cores, so that all the hydrogen they put in gets fused, and not just a few atoms here and there.
It's low in the core too, just not quite that low.
How does nobody else here know that we're talking about artificially fusing some blend of deuterium or tritium? The sun fuses ordinary hydrogen at this point in it's evolution - that's why it's a nice slow 10 billion year burn.
Why do people assume that scientists don’t sanity check themselves? Genuine question, no offense to the OC here.
Cause maybe they assume scientists are hyping things up like VCs for AI.
In a dishonest world, the honest would be mistrusted more.
"guys, I know we've been working on this for decades, but I've been going over this first-year textbook, and I have some bad news..."