Protons are so small that a little dib of ink like the dot on this i can hold something in the region of 500 billion of them, rather more than the number of seconds contained in half a million years.
i上的这样大小的一滴墨水,就可拥有约莫5000亿个质子,说得更确切一,组成1.5万年的秒数还多。
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