Here's to blue skies (but just today)

Photo of the annular solar eclipse of 20 May 2012,
Monterey, California - by Sally Cullen

Today's message from the Cloud Appreciation Society:

Today, we finally accept the value of blue-sky thinking – but only along the path of totality for the forthcoming solar eclipse. This path stretches diagonally across the United States like an enormous sash of shadow. It is where the Moon, as it passes directly between us and the Sun, will obscure all but the solar corona. The shadow appears total because the Sun and Moon look almost exactly the same size in the sky. This is thanks to a cosmic coincidence: the Sun, which is 400 times wider than the Moon, happens also to be around 400 times more distant (though the distances vary at different points in the orbits). Celestial bodies move with such regularity that the precise times and locations of solar eclipses are easily calculated hundreds of years in advance. Compare that to the turbulent dance of water through our atmosphere. The ungovernable chaos of the clouds means we can barely predict a few hours in advance whether this grand display of celestial obstruction will itself be obstructed from view.

This photo (above) was taken by Sally Cullen during the annular solar eclipse of 20 May 2012 - the sun can be seen peeking through the Stratocumulus clouds over Monterey, California. An annular solar eclipse is when their relative distances from Earth mean the Moon appears slightly smaller than the Sun and so doesn’t cover it completely.