The fastest body, and the one that makes a birth time indispensable.
The Moon covers twelve to fifteen degrees a day. Over the twenty-four hours a dateless chart is uncertain by, it can cross half a sign — and sometimes a whole boundary. This is the single strongest argument for recording a birth time.
Its speed swings widely because its orbit is markedly eccentric: near perigee it runs at over 15° a day, near apogee under 12°. A chart's Moon speed is worth reading for that reason alone.
Cancer is the only sign it rules, and the only sign in any scheme ruled by a single luminary. Lilith, also plotted here, is not a body at all but the far point of this same orbit.
What it is
Earth's satellite. The only body in the chart that orbits us rather than the Sun.