[…] why not have a watch sized device that can store insane amounts of power?
Because Hiroshima was leveled by “only” 20 MWh (cost ranges from 120€ in northern Scandinavia to 1010€ in Greece) so having people carry energy wallets with enough to make more around day to day is like paying your groceries bill with C4 (which is perfectly save as long as there is no primary explosive).
gandalf_der_12te@discuss.tchncs.de 16 hours ago
the physics limit to the density of energy is literally a black hole. it compresses the maximum amount of mass (energy) into a space. but that’s technologically useless since you can’t extract the energy out of it on-demand.
The densest ways of storing energy that are technologically useful are:
There’s also speculative technologies like antimatter (24 * 10^9 kWh/kg) which aren’t available today.
Source
GraniteM@lemmy.world 10 hours ago
The beauty of using uranium as currency is that if anyone hoards too much of it, the problem takes care of itself.
absentbird@lemmy.world 12 hours ago
So one gram of antimatter could power a modern city for like three months? That’s wild.
brotundspiele@sh.itjust.works 16 hours ago
There actually is a method that could be used to extract energy out of a black hole. Probably not something you’d build in a watch-sized device though.
gandalf_der_12te@discuss.tchncs.de 16 hours ago
it only seems to work for rotating black holes though?
brotundspiele@sh.itjust.works 15 hours ago
Yeah, that’s why you have to wind up your watch every now and then. To spin up its internal black hole again.
HeyThisIsntTheYMCA@lemmy.world 14 hours ago
just drink more it’ll start spinning soon enough
muts@feddit.nl 15 hours ago
Don’t they all spin though? As in any matter falls in one way or another angular momentum is gained.
WorldsDumbestMan@lemmy.today 16 hours ago
If the well, event horrizon expands when a blackhole takes more mass, why can’t we just figure out how much volume it is compressed into by measuring the event horrizon increase?
We know the matter that goes in is a certain size. Maybe we can deduce the total size it is compressed to? And the size the blackhole gains.
rtxn@lemmy.world 15 hours ago
It’s impossible to know based on the current understanding of physics. A black hole is formed when the inward gravitational force exceeds the neutron degeneracy pressure of a sufficiently massive object, which is what keeps neutrons from occupying the same space (not really, it’s complicated). Beyond that, only conjecture exists with no evidence.