Astronomy Picture of the Day . ... Perigee Moon, Apogee Moon . ... Tonight, those blessed with clear skies can enjoy a glorious full moon, the last full moon of the "Y1.9K"s. In fact, tonight's moon will be a full-perigee-solstice moon, reaching its full phase and perigee (the closest point in its orbit) on the solstice, the first day of northern hemisphere winter. ... Lava Fountain on Jupiter's Io . ... Our Sun is unusual in that it is alone - most stars occur in multiple or binary systems. ...