The summer solstice. What the longest day does to children's energy.

The summer solstice in New York produces a specific kind of child energy. It is the energy of the day that doesn't end. By eight in the evening the light is still full, and my daughter, who has been up since six and busy since seven, is showing no signs of the tiredness that should have arrived three hours ago. She is running on light. The photons are doing something to her circadian system that is keeping the sleep pressure at bay.

The solstice is the longest day. In New York it is 15 hours and 5 minutes of daylight. In Stockholm it is 18 hours and 37 minutes. This is not a metaphor. It is a biological fact with biological consequences. The child who is still awake at ten on June 20th is not being deliberately difficult. Their brain has not received the melatonin signal that normally arrives around 8:30pm. The melatonin signal is suppressed by the light. The light is still on.

I have started using the solstice deliberately. Not ceremonially — we don't have traditions for it yet. But attentionally: going outside at sunset, noting that we are at the year's longest point, saying so. My daughter set an alarm last year. We watched the sun go down from the roof. She said: it'll be a little earlier every day now until December. Yes. That is exactly right.