A crow flies up, and is gone in an instant.

The Moon circles the Earth monthly, as it has for about the 4 billion year life of Earth. Locked in by lunar tidal forces, it now turns the same face to us all month. Dragged by Earth’s tides, the Moon is gradually gaining energy and angular momentum, spiraling outwards at about 3.8 centimeters a year; this drag also increases the length of our day, but only about 2.4 milliseconds/century – don’t hold your breath to wait to detect this. Here, the Moon is a pale light shadow on the deep blue sky.

These rocks were born deep under the surface, under conditions of extreme heat and pressure. I think they gradually rose near the surface, then were exposed by erosion; I have no idea of the time frames involved.

The blue sky above has been with us almost as long as the Moon has. Occasionally adorned by clouds or mist; darkened and shaded by smoke from wildfires, ejecta from volcanoes, and debris from comets, it greets us each morning and shelters us day and night. Humans are adding foreign substances to it; it remains sky blue.

This tableau appeared as our walk began. Coyote Valley Open Space Preserve, 4/2/2024, 9:29 am.