Country diary: Reflecting on a moonlit night | Mark Cocker

I have a habit, if I wake some nights, to get up and go downstairs to read. Last night was noteworthy because I could see the moon as a mere horn repeatedly swallowed then reborn from the passing clouds. Through binoculars, however, I could make out the other portion of the whole lunar sphere as a sort of ill-lit inference.

It was Leonardo da Vinci who first suggested that this shadow part of the crescent moon is visible because of sunlight rebounding off the Earth and then re-transmitted on our one satellite. It was wonderful to imagine that the energy received here, even as I stood gazing, was re-presented out there a little over a second later. That is because light travels at a speed per second roughly similar to our distance from the moon (the respective figures are about 300,000 km/sec and an average 384,400 km).

The fact that the gap between our planet and our satellite varies according to the lunar orbit was manifest last month in that fantastically enlarged sphere we call a hunter’s moon. I judge the name a rather sad reflection on our species, given that the last thing it inspired was a wish to kill. Rather, it evoked the connectedness of planet, satellite and star in all life’s processes.

On that particular evening I’d also got up to read, and suddenly was aware of silver moonflare flooding the back bedroom. It arrived in a narrow lozenge at the window, but then pooled across our Welsh blanket as intense colour bathed in ethereal whiteness. Recall that the light had taken its customary second to arrive from the moon. However, the gamma rays that first gave birth to that energy at the core of the sun, where the atmosphere is 13 times the density of lead, may take thousands of years rising through the intervening plasma to reach our star’s surface. The resulting photons then travel to Earth – here as moon-inflected light – in just eight minutes, but the whole process entailed in that momentary vision may be as old as our species. Our world is truly, in Henry Williamson’s words, a chronicle of ancient sunlight.

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