[greggsy]

Perpetual motion and free energy stuff was interesting things to read about back in early 2000’s internet (around the time when conspiracy theories were kind of niche).

The only thing of interest recently has to be the EmDrive [1] - only because the rigorous testing it was put through finally put the mail in the coffin of backyard free energy nuts.

https://en.wikipedia.org/wiki/EmDrive

[quickthrower2]

Nuclear fission energy is for practical purposes as good as perpetual motion

[Schroedingersat]

Most Uranium ore is roughly as energy dense as anthracite.