Unawaka mwanga. Hakuna anayeweza kuuona.

Kaa katika chumba chenye giza kabisa na bado unatoa mwanga. Ngozi yako hutoa muwako hafifu, mfululizo, na hauna uhusiano wowote na joto la mwili.

Sit in a completely dark room and you are still giving off light. Your skin emits a faint glow, continuously, and it has nothing to do with body heat.

Timu ya Kijapani ilithibitisha hilo mwaka wa elfu mbili na tisa. Waliweka watu waliojitolea, waliovua nguo za juu, katika chumba kisichopitisha mwanga na kuelekeza kamera nyeti sana kwao kwa dakika ishirini kila mara. Kamera ilinasa muwako thabiti, usiosawa, ukitoka kwenye ngozi, ukiwa mkali zaidi karibu na uso. Muwako huo ni matokeo ya kemia ya kawaida ndani ya seli zako: miitikio inayohusisha oksijeni hutoa chembe moja moja za mwanga zinapoendelea.

A Japanese team proved it in two thousand and nine. They put volunteers, stripped to the waist, into a light-tight room and pointed an extremely sensitive camera at them for twenty minutes at a time. The camera picked up a steady, patchy shine coming off the skin, brightest around the face. The glow is a by-product of ordinary chemistry inside your cells: reactions involving oxygen throw off single particles of light as they go.

Kuna kizuizi, na hicho kinaeleza kwa nini hakuna aliyewahi kutambua. Mwanga huo ni dhaifu mara elfu moja hivi kuliko kitu hafifu zaidi ambacho jicho la binadamu linaweza kutambua. Hutauona kamwe, wala hakuna mtu mwingine atakayeuona. Utafiti huo huo uligundua kuwa muwako huo hupanda na kushuka wakati wa siku, ukiwa dhaifu zaidi asubuhi na mkali zaidi jioni, jambo linalomaanisha kuwa mahali fulani katika hili, uso wako una ratiba yake mwenyewe.

There is a catch, and it explains why nobody ever noticed. The light is roughly a thousand times weaker than the faintest thing a human eye can detect. You are never going to see it, and neither is anybody else. The same study found the glow rises and falls across the day, weakest in the morning and strongest in the late afternoon, which means that somewhere in all of this your face is keeping a schedule.