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Suppose I'm able to build a huge analog clock, with a seconds hand very long. I want have hand end running at light speed (300,000 km/s). Needle then has to be 300,000km*60s/(2pi) = about 2,864,788km (or 2,8*109m).
Not too bad, it's more-or-less 7 times distance Earth-Moon.
Question is... if I build the hand like a "cable" 1-copper atom thick (copper atom has a diameter of 2.5*10-10m), I will have a needle made by (2.8*109)*(2.5*1010) atoms, aka about 7*1019 atoms. Since 1g of copper has 6.02*1023/6.3 atoms, aka about 9.5*1022 atoms, our needle has a weight of about 0.0007g. Good, not too expensive.
Well, it is possible to have a needle running at that speed? And since I can (obviously) build a needle longer, what happens to its end, when clock runs? Is it possible to run a clock like that? How many energy do I have to put to run the clock, if possible?
Thank you :)