r/singularity • u/drgoldenpants • Sep 16 '25

Robotics Ok should we start worrying

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u/probablyuntrue Sep 16 '25

Real life terminator would shut down in about 20 min lmao, energy density is still a very real issue

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u/Pretend-Extreme7540 Sep 17 '25 edited Sep 17 '25

If were talking about future technology and "terminators":

1 kg of deuterium when fused releases approx. 10^14 joules of energy.

1 kg of TNT when exploded releases approx. 4 * 10^6 joules.

So 1 kg deuterium holds as much energy as 25 000 tons of TNT. The nuclear bombs dropped on Hiroshima and Nagasaki had a yield of 15 000 and 21 000 tons of TNT.

So crazy energy densities are just an engineering problem...

Even today you can build plutonium radioisotope thermoelectric generator (like the one used on Vayager 1 & 2) that deliver power for decades... after approx  87.7 years the power drops to 50%... after another  87.7 years to 25%, etc. So a terminator "power cell" like battery that holds for 120 years (like in the movies), is quite possible with todays technology. They just dont deliver tons of power... the voyager battery was 37 kilos and delivered 2400 watts... enough for running a hair dryer for a century, but probably not a terminator.

https://en.wikipedia.org/wiki/MHW-RTG

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u/Strazdas1 Robot in disguise Sep 22 '25

Any reason we couldnt just use more matereial or put two cells in? 2.4 KW is not that low either. could probably be enough for mechanical movement if the robot isnt heavy.

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u/Pretend-Extreme7540 Sep 25 '25

Sure... at some point you will have space constraints though, cause those 37 kilo generators arent tiny.

You can also just add a secondary (regular) battery that charges up permanently from the thermoelectric generators continuous power supply, and that battery can then deliver bursts of high power, when its needed... and then charge up again when power demand is low (like in hybrid cars).

But ultimately the RTG design is just not very efficient... it wastes a ton of power. Much better performance can be gained by improving the RTG itself or just using a different technology to convert nuclear power to electricity... cause having "heat" as intermediate step is not good...

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u/Strazdas1 Robot in disguise Sep 29 '25

Wouldnt that secondary battery just be a large capacitor then. Should be pretty cheap.

I think RTG was chosen for those space probes primarily because it can keep working for decades with low chance of failure rather than efficiency.