How long is the sun's day?

Answer 1

The length of a planet's day is time of one rotation relative to the Sun. So of course that definition has no meaning for the Sun itself. But the Sun does rotate, and that rotation can be timed, although as a gaseous body its rotational rate is irregular. Additionally, the Sun's "day," or period of one rotation, is different depending on which viewpoint is used, the Sun's or ours. # The sidereal rotation period, the time for one complete revolution of the points on the Sun's equator from the Sun's point of view, is about 25.38 Earth days. # The synodic rotation period, the time for a point on the Sun to make one rotation as viewed from the moving Earth, is about 27.2753 Earth days. You may see Related Links for more on this subject.

Answer 2

It is always day on the sun. There is nothing there to block the light and cause night.