Even a relatively quiet day on the Sun is busy. This ultraviolet image shows bright, glowing arcs of gas flowing around the sunspots. Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They correspond to concentrations of magnetic field that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere. Sunspots usually appear in pairs, with pair members of opposite magnetic polarity. The number of sunspots varies according to the approximately 11 year solar cycle.