Comment on life pro tip!!
qjkxbmwvz@startrek.website 6 months agoMeme is referring to nuclear reactors, not complete antimatter annihilation.
Nuclear reactors don’t “burn” everything — most of the matter stays (this is what nuclear waste is). So you can only apply E=mc^2 to the difference in mass, not the mass of the fuel.
The numbers don’t add up. If you can get 21 billion food calories from total annihilation (which I checked is right), you’d get nowhere near 18 billion food calories from a fusion reaction. Maybe if works if you assume “calories” for the fission reaction means metric calories, since food calories are metric kilocalories.
I hate the way the word “calorie” ended up with two wildly different definitions.
Yeah, I looked up energy density assuming fast neutron reactor, and it’s “only” 7 million US food calories.
US calories are equal to the real metric unit of kilocalories. Maybe the meme above used real calories
Can they really get out THAT many calories from a gram of Uranium?! That’s insane!
I wish I cared more and would verify it
Calories are just a measure of the energy released by a material.
Normally they’re measured by burning the material, so it’s not really accurate to say that you can get that many calories from uranium. On the other hand the whole concept is fucking stupid anyway, because it’s measured by burning the material. Technically, a kilo of dry sawdust has 4800 calories (more than double the daily calorie requirement of the average person).
I just googled around and I think the meme inflated the numbers. Fast neutron reactor gets 28GJ/g, which is “only” about 7 million food (kilo) calories.
Krauerking@lemy.lol 6 months ago
You know it’s funny, technically a calorie is just a measure of how much energy it takes to heat up 1 gram of water 1° C I never really thought about it but it could totally be applied to other things and nuclear reactor plants that literally just heat up water to spin a turbine would be the perfect thing to measure in calories. So would regular electric plants for that matter.
Oh shoot that would be some wild math to figure out how hungry they all are.
datelmd5sum@lemmy.world 6 months ago
Except that 1 gram of water is at 1 bar. Heating up 1 gram of water from 300°C to 301°C takes 1.38 calories.