Mean solar day is the time interval between two successive noon when sun passes through zenith point (meridian). Sidereal day is the time interval between two successive transit of a distant star through the zenith point (meridian). By drawing appropriate diagram showing the earth's spin and orbital motion, show that mean solar day is 4 min longer than the sidereal day. In other words, distant stars would rise 4 min early every successive day. As per diagram, the earth moves from the point P to Q in one solar day.

Mean solar day is the time interval between two successive noon when s

1.	Mean solar day is the time interval between two successive noon when sun passes through zenith point (meridian). Sidereal day is the time interval between two successive transit of a distant star through the zenith point (meridian). By drawing appropriate diagram showing the earth's spin and orbital motion, show that mean solar day is 4 min longer than the sidereal day. In other words, distant stars would rise 4 min early every successive day. As per diagram, the earth moves from the point P to Q in one solar day.
Answer» Solution :`implies` As per diagram , the earth moves from the point P to Q in one SOLAR DAY Every day the earth advances in the orbit by approximately `1^@` . Then, it will have to ROTATE by `361^@`(which we define as 1 day) to have the sun at zenith point again. `:. ` To COVER `361^@` , time taken = 24 h `:. ` To cover `1^@` , time taken = t, `t = (24)/(361) xx 1 = 0.066 h ` `= 3.99 min` `~~ 4 min` Hence, distant stars would rise 4 min early every SUCCESSIVE day .