Answer: perpetualmotion

AnswerCrossword Clue
PERPETUALMOTION

Nonstop action

PERPETUALMOTION

Scientific impossibility?

PERPETUALMOTION

Theoretical unending phenomenon

PERPETUALMOTION
Mad scientist's dream
PERPETUALMOTION
Object of many a hopeful machine inventor's search
PERPETUALMOTIONTheoretical physical concept
PERPETUALMOTIONPhysics impossibility
PERPETUALMOTIONPhysicist's fanciful quest
PERPETUALMOTIONInventor's impossible goal
PERPETUALMOTIONMechanical mirage.
PERPETUALMOTIONMechanical impossibility.
PERPETUALMOTIONOne of the "impossibles."
PERPETUALMOTIONPhysicist's fascination.
PERPETUALMOTIONInventor's dream.
PERPETUALMOTIONInventor's dream
PERPETUALMOTIONAsset of an ideal machine
PERPETUALMOTIONAn impossible dream
PERPETUALMOTIONAncient scientific quest
PERPETUALMOTIONInventor's "impossible dream"
PERPETUALMOTIONNoted Paganini composition
PERPETUALMOTION"Impossible" achievement
PERPETUALMOTIONMechanical impossibility
PERPETUALMOTIONViolation of the first and second laws of thermodynamics
PERPETUALMOTIONScientific impossibility
PERPETUALMOTIONImpossible achievement
PERPETUALMOTIONFrictionless-environment concept