Earth's orbit

The earth goes around the sun once each year while meanwhile rotating about its axis once each day.
A sidereal day is the time from starrise to starrise.
A solar day is the time from sunrise to sunrise.

Which of these is 24 hours long?
Which is longer?

Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA soper@bovine.uoregon.edu