this post was submitted on 09 Apr 2025
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Science Memes

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[–] Blue_Morpho@lemmy.world 0 points 2 months ago (8 children)

Uranium generates that energy by fission. The hydrogen in sugar could generate huge amounts of energy if fused.

[–] Suoko@feddit.it 0 points 2 months ago (1 children)

For comparison:

  • Chemical combustion of uranium: ~4.7 MJ/kg
  • Nuclear fission of uranium-235: ~83.14 TJ/kg (or $ 83.14 \times 10^6 , \text{MJ/kg} $)
[–] qaz@lemmy.world 0 points 2 months ago (2 children)

Do you have a Lemmy client that supports mathematical functions?

[–] Suoko@feddit.it 0 points 2 months ago* (last edited 2 months ago) (1 children)

With ollama, having smart local bots for your lemmy instance should be easy

[–] qaz@lemmy.world 0 points 2 months ago

Did you reply to the wrong comment?

[–] MBM@lemmings.world 0 points 2 months ago

Built-in LaTeX support would be so cool (and not that hard, Mathstodon has it)

[–] Ledericas@lemm.ee 0 points 2 months ago

If you can do nuclear fusion yea, it's more efficient. Cold fusion has been a sci Fi thing for a while; they mostly moved on to antimatter-matter annihilation, and ZPE(seems to be a favorite for sg1)

[–] IrateAnteater@sh.itjust.works 0 points 2 months ago (3 children)

How much more energy would you get if you fused uranium?

[–] PunnyName@lemmy.world 0 points 2 months ago (2 children)

Ask Hiroshima and Nagasaki.

In alphabetical order.

[–] davidgro@lemmy.world 0 points 2 months ago (1 children)
[–] PunnyName@lemmy.world 0 points 2 months ago

I stand corrected, because I done forgetted.

[–] Blue_Morpho@lemmy.world 0 points 2 months ago (3 children)

Those are fission. Fusion bombs don't fuse uranium. They use a fission bomb to fuse Lithium.

[–] frezik@midwest.social 0 points 2 months ago

Oh, they do, but not as the primary or secondary. You can wrap depleated uranium around the core to capture fast neutrons that are leftover from the rest of the process. Changing the number of layers is how you can dial in a desired yield.

[–] anindefinitearticle@sh.itjust.works 0 points 2 months ago (1 children)

Fusion bombs use a fission bomb to fuse Hydrogen, which is why they're called H-bombs.

[–] Blue_Morpho@lemmy.world 0 points 2 months ago (1 children)
[–] peoplebeproblems@midwest.social 0 points 2 months ago (1 children)

I mean if we really want to be technically accurate here, the lithium is just a moderater for the hydrogen isotopes to fuse.

But for me it gets fuzzy when looking at the reaction.

LiD is 4 protons, 8 neutrons. Add a new neutron, and bam, you have 4 protons and 9 neutrons. But that's where it gets weird to me. The lithium needs to decay or something into a tritium and dueterium which forces the tritium to fuse with the existing dueterium in the LiD molecule? Clearly the neutron has enough energy to transfer into one of the atoms to increase the chance of tunneling actually occuring.

[–] ChickenLadyLovesLife@lemmy.world 0 points 2 months ago

The only real purpose of the lithium deuteride is that it's a dry, shelf-stable, room-temperature fuel. The very first hydrogen "bomb" (actually a building-sized device) used supercooled liquid hydrogen as the fusion fuel, but this was obviously not practical for a deliverable bomb.

[–] ChickenLadyLovesLife@lemmy.world 0 points 2 months ago

For that matter, even the Nagasaki bomb ("Fat Man") didn't use Uranium at all - its fuel was Plutonium.

[–] Blue_Morpho@lemmy.world 0 points 2 months ago

Using the rule of thumb, anything heavier than iron requires energy input to fuse. So you lose energy fusing uranium.

[–] davidgro@lemmy.world 0 points 2 months ago* (last edited 2 months ago)

Serious answer: A huge negative amount. Anything above iron requires energy to fuse (which is why it produces energy from fission.) and I'm pretty sure nothing with 184 protons could be stable enough to count as being produced - the nuclei would be more smashed apart than merging at that point.

[–] desktop_user@lemmy.blahaj.zone 0 points 2 months ago (1 children)

and all would generate the same if thrown to something capable of lossless e=mc^2 conversion (maybe a black hole)

[–] sga@lemmings.world 0 points 2 months ago (1 children)

sadly black holes go to something like 42% conversion (source: some minute physics video i think)

[–] hemko@lemmy.dbzer0.com 0 points 2 months ago (1 children)

That's quite interesting. Is it because of the light produced when the materia starts spinning around in the accretion disk in very high speeds? I doubt hawking radiation would do anywhere near that much

[–] sga@lemmings.world 0 points 2 months ago (1 children)

https://youtu.be/t-O-Qdh7VvQ

No, It is actually the light produced that we can actually use as a energy source, the limiting thing is, before completely loosing its kinetic energy to frictional heat, stuff falls into black hole, from where we can not get anymore energy back. If black hole is stationary, then its 6%, and if its spinning (and assuming the fastest spinning theoretically possible) - 42% (spinning black holes are smaller and have smaller radius of no-return

[–] hemko@lemmy.dbzer0.com 0 points 2 months ago (1 children)

Ahhh alright I was thinking the black hole converting mass to energy for itself, not as if we were to try utilize it

[–] sga@lemmings.world 0 points 2 months ago

we can't let the noble black hole keep all ye energy, ye shall liberate it

[–] Redex68@lemmy.world 0 points 2 months ago

Whilst I get your point, their point is still valid in the sense that you just can't extract that energy from gasoline in a more efficient manner than just burning it. For practical purposes, gasoline truly is that much less energy dense.

[–] TheTechnician27@lemmy.world 0 points 2 months ago

And this boulder could generate huge amounts of energy if I pushed it up to the top of Mt. Kilimanjaro and let it roll down.

44 upvotes and 0 downvotes for a comment that doesn't understand that energy density measurements like this tend to measure the useful energy of a system.

[–] nialv7@lemmy.world 0 points 2 months ago (4 children)

It's disappointing that natural selection didn't figure out fusion.

[–] SkyeStarfall@lemmy.blahaj.zone 0 points 2 months ago* (last edited 2 months ago) (1 children)

It's good it didn't, otherwise it's possible that all the hydrogen in the ocean would be fused into helium by now

Well, more likely it would significantly heat up earth due to the amount of energy released first, cooking everything/starting an endless cooking->extinction->cooling cycle

[–] explodicle@sh.itjust.works 0 points 2 months ago (1 children)

On the fusion planet: "Man, can you imagine if early life figured out how to make poisonous oxygen gas?"

[–] LarmyOfLone@lemm.ee 0 points 2 months ago

*in a silly high voice due to all the helium

[–] ryannathans@aussie.zone 0 points 2 months ago (1 children)
[–] DoYouNot@lemmy.world 0 points 2 months ago* (last edited 2 months ago)

I mean, technically it already has.

[–] Trollception@sh.itjust.works 0 points 2 months ago* (last edited 2 months ago)

We have fusion (hydrogen) bombs. We just haven't figured out how to maintain and efficiently harness it for energy.

[–] WhiskyTangoFoxtrot@lemmy.world 0 points 2 months ago

It figured out photosynthesis instead. Why do your own fusion when you can just take advantage of the fusion that's already happening?

[–] dalekcaan@lemm.ee 0 points 2 months ago

In theory, yes. In practice, of those two only fission is currently viable.