I understand that the Laws of Thermodynamics imply that no form of perpetual motion machine is possible in an isolated system.
But, isn't it the case that light seems to go on forever. The light from stars millions of light years away, millions of light years ago, bring us energy and momentum today. This seems quite contradictory to me.
This is my understanding of the fact that the Laws of Thermodynamics imply no perpetual motion: Every form of energy ends up as internal energy of astronomical bodies and there is no way to convert it back to other forms with 100% efficiency. If this is true, then this is the contradiction: It seems light will rarely end up as internal energy, compared to other forms at least. Or we would not have detected light from stars millions of light years away, millions of light years ago.
- Thus if u use light to power something, will perpetual motion be possible?
- What is the reason for light's high resilience to end up as internal energy ( at least as compared to other forms of energy )? How does this relate to QED's way of treating matter-light interactions?