Timeline for What is the closest to a perpetual motion machine that could be made to work in space?
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Apr 13, 2016 at 12:18 | comment | added | Steve | @HowardMiller I understand that ... Re-reading the question I see "closest to perpetual motion", so I guess I have to give a little slack in the interpretation. | |
| Apr 13, 2016 at 0:36 | comment | added | Howard Miller | @Steve The second law of thermodynamics prevents perpetual motion. | |
| Apr 12, 2016 at 19:18 | comment | added | Steve | @HowardMiller is correct, it's not the photons that cause the motion, it's the gas inside the bulb. Also, when I think "perpetual motion", I think a requirement is motion without any external energy added - which is exactly what those photons are introducing to the system. | |
| Mar 20, 2016 at 2:02 | comment | added | Howard Miller | I used to have a Crooke's Radiometer. It has four triangular vanes in an evacuated bulb. Each vane is white on one side and covered with lamp black on the other. The remaining air in the bulb tends to stick to the black side of the vanes, but light causes the vanes to warm up, and the air molecules 'pop' off, causing the vanes to turn. | |
| Mar 20, 2016 at 1:26 | history | answered | SF. | CC BY-SA 3.0 |