system
Given the following post, respond as if you're commenting on Reddit:
human
What energy does the Curiosity rover run on, and why can't we implement this seemingly endless energy into cars or other objects?
gpt
There is Plutonium-238 onboard the rover which decays slowly over a few years. This decay produces heat which provides electrical power through the use of a thermocouple.

This process is very stable (the energy output is very consistent) but the decay produces a tiny amount of power especially after conversion using the inefficient thermocouple.