Verified answer

24 hours is the time it takes the earth to rotate to face the sun at the same spot (a solar day). But that is longer than the time it takes to rotate 360 degrees.

The sidereal day is the time it takes to rotate 360 degrees.

One way to calculate this is that after a year, the earth has "lost" a day because the sun has swung one time around the earth. So although a year gives you 365.25 sunrises, the earth rotated 366.25 times.

time to rotate = 365.25 * 24 hours / 366.25

time to rotate = 86164s

time to rotate = 23 hours, 56 minutes, 4 seconds

A sidereal day which is the time Earth takes to rotate 360° relative to the stars, is just about 4 minutes shorter than a solar day.

Sidereal days are mainly used by astronomers to adjust telescopes.

A sidereal day is 23 h, 56 m, 4.09053 seconds.

Earth rotate every 23 hours, 56 minutes and 4 seconds.

Rohn

It's not exactly 24h.

Ever wondered why there is an additional day every 4 years, Feb29 (=365.25 days per year) and one every 400 years (=365.251 days per year) ,but not ... (I forgot)?

There are about 365.2422 days per year. But our clocks count 24h.

you do the math.

but it is 24 hours!