The Order of Time by Carlo Rovelli

Imagine a weird point in your life when nothing happens—a window opens in your mind where time, to your utter astonishment, looks very different than the uniform universal flowing you thought it was. The present ceases to exist. You’re left with familiar sensations or traces from the past and an open sense of possible alternative futures. Time is like “holding a snowflake in your hands”—it vanishes as you contemplate it.