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If every thing in the universe suddenly doubled in size, and the physical constants changed accordingly, would we notice any effects?

if not, how can we possibly say if its not happening right now. what if everything's growing in size and the constants with it and we dont even know?

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marked as duplicate by John Rennie cosmology Jun 22 '18 at 15:14

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We would notice. Suppose your body's dimensions doubled in size - you're now twice as tall, twice as wide, and twice as deep, meaning you have 8 times your original mass. Your muscle strength is proportional to the cross-sectional area of the muscle, which has doubled in width and depth, only increasing by a factor of 4. You will struggle to move, since you have to carry an 8x heavier body with only 4x stronger muscles. There's a reason why animals don't get arbitrarily large!

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  • $\begingroup$ What, however, causes increase of mass? The premise was that "ALL" lengths scaled, including size of atoms; but that doesn't include weight or mass. $\endgroup$ – Whit3rd Jun 23 '18 at 19:48

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