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.

像字母i上的点这样大小的一滴墨，有莫5000亿个质子，说得更确切一点，要比组成1.5万年的秒数还多。