On the ground our world might seem green like the deep green spruce forests. It might be a burnt ochre like the Saharan desert, or yellow, like the fields in August. But seen from the outside, our world is blue. Blue like the sky – even if one is in the sky looking down at the world. So perhaps, then, it is the sky that is blue, between us and the world?

From the stratosphere, our marble is blue because of the sunlight that scatters in the oxygen- and nitrogen-rich sky. If we had more sulphur in the sky our marble would be yellow like Venus – but we would not be able to breathe, at least not with our current physiology.

Yellow is the color of the sun, energy, and joy. It is also the color of warning, both in traffic and on a wasp. Whereas blue is calming, quieting, and heart-rate lowering, like the constant sky and sea. But what if we lived on Venus? Would we then be conditioned to feel calm, secure, and at peace when surrended by yellow?

Random thoughts in the stratosphere above Stockholm on an April evening.

(Stockholm, Sweden; April 2016)