why is there a 4-minute differnce between the solar day and the sidereal day? was this ever explained?
2007-02-04 10:10:45 · 2 answers · asked by ast10177 1 in Science & Mathematics ➔ Astronomy & Space
The sidereal day relates to the relative position of a point on the earth and the stars, while the solar day relates to the relative position of a point on the earth and the sun.
For this question just consider that the stars are at an infinite distance. As we revolve around the sun (looking downward toward the earth from above the north pole) the earth rotates in a counterclockwise direction. On a given day, say that a given point on the earth points toward a star at midnight. The next day the earth has moved about 1/365th of the way around the sun (call it a degree), but the star hasn't "moved". So, the next night the earth gets to the same star about 4 minutes earlier (it doesn't have to rotate as far). But, because the sun and earth are in the same relative position the earth has to rotate the full distance to get from noon to noon. By drawing a diagram you can easily see the difference.
2007-02-04 10:46:14 · answer #1 · answered by David A 5 · 0⤊ 0⤋
Solar days cover the rotation of the Earth, siderials days cover the motion around the sun and the rotation of the Earth and we have 1 degree per day thus the stars in the sky will not be in exactly the same place at the same time the next day.
2007-02-04 10:30:58 · answer #2 · answered by Anonymous · 0⤊ 1⤋