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As far as I know photons don't have mass but they do have momentum ($p=mv$). Scientists say that if we put a shiny (reflective) shield of large radius in the vacuum of space, then light from sun will will start moving the shield. How can these two facts be commensurate?

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marked as duplicate by Kyle Kanos, John Rennie, Willie Wong, dmckee Feb 19 at 16:02

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okay got it! it doesnt have nothing to do with momentum the electric charges that forms light make it sail.. –  Arun Malik Feb 19 at 15:46
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It does have everything to do with momentum. Light does not have charge or mass, but it does have momentum. en.wikipedia.org/wiki/Photon#Physical_properties –  Hans-Peter E. Kristiansen Feb 19 at 15:56
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It comes down to them having momentum, which brings us to physics.stackexchange.com/q/2229 –  dmckee Feb 19 at 16:01