## Query

Mercury's orbital period. The period of Mercury's orbit is 7.602 x 106 seconds and that of Earth is 3.157 x 107 seconds. What is the value of Mercury's period in Earth-years?

Mercury's revolution in one century. How many revolutions around Sun does Mercury make in one century (100 Earth-years)? How many degrees of angle are traced out by Mercury in one century?

Correction factor. The mass M of Sun is 1.477 x 103 meters and the radius rQ of Mercury's orbit is 5.80 x 1010 meters. Calculate the value of the correction factor 3/W/r0 in equation [14].

Advance angle per century in degrees. Using equation [14], multiply your answers from Queries 13 and 14 to obtain a prediction of the advance of the perihelion of Mercury's orbit per century in degrees.

Advance angle per century in seconds of arc. There are 60 minutes of arc per degree and 60 seconds of arc per minute of arc. Multiply your result from Query 15 by 60 x 60 = 3600 to obtain your prediction of the advance of the perihelion of Mercury's orbit per century in seconds of arc.

A more careful analysis predicts a value of 42.98 seconds of arc (0.0119 degrees) per century (see Table 1). The observed rate of advance of the perihelion is in perfect agreement with this value: 42.98 ± 0.1 seconds of arc per century. (See references.) How close was your prediction?

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