Telling Time

• At time 1, The Sun Is Directly Overhead..

• After 1 Earth Rotation (23^h 56^m), The Sun Is No Longer Overhead Since The Earth Has Moved ~1^o In Its Orbit..

• For The Sun To Be Overhead Again, The Earth Must Rotate Another 1^o

How Long Does That Take?

• Therefore, For The Sun To Go From Zenith To Zenith Takes 4 Minutes Longer Than For A Star……

1 Mean Solar Day = 24^h

Q: Why Is It Called A Mean Solar Day?