“All things are transient,” said my scientific collaborator, with just a hint of irony. From up in the hills at Berkeley Lab, where we study the way that light and matter interact, he meant it in three senses:

• We use “transient absorption spectroscopy” to study the changes in a material after it is exposed to light. The new states we create are transient.
• The gentle blue-hour conditions of this picture are transient; the light was completely different ten minutes later.
• Berkeley Lab sits atop the Hayward Fault; a large earthquake could topple the lab at any time.

In the face of all of that transience… Might as well go for a drive.