The human body gives off a faint glow of visible light, produced by ordinary chemical reactions inside living cells. It is real light, but it is far too weak to see: roughly a thousand times below the sensitivity of the naked eye, so to us the body appears completely dark.

The human body gives off a faint glow of visible light, produced by ordinary chemical reactions inside living cells. It is real light, in the range our eyes are built to see. It is also far too weak for us to notice, running at roughly a thousand times below the sensitivity of the naked eye, [...] The post The human body gives off a faint glow of visible light, produced by ordinary chemical reactions inside living cells. It is real light, but it is far too weak to see: roughly a thousand times b