Shadows

The sun has almost set and it's nearly time to start working, but I rarely pass an opportunity to take a quick stroll outside while there's still enough light. Today I glance around and nearly every one of the hundreds of tourists up here this evening are looking to the west, out over the Pacific Ocean. They're watching the sun sink below the clouds thousands of feet below us. Perhaps they'll be fortunate enough to witness a green flash - they'll be luckier than I if they do.

Only a few of tonight's visitors realise that if they look to the east they will see a phenomenon they've probably never witnessed before, the shadow of a mountain in the sky. The dark triangle in the picture below is Mauna Kea's shadow. Beyond that a band can be seen in the darkening sky, the shadow of the Earth itself.

What an extraordinary place this is.