Job 31:26

Viewing the 1769 King James Version. Click to switch to 1611 King James Version of Job 31:26

If I beheld the sun when it shined, or the moon walking in brightness;

The Earth's natural satellite. United States and Soviet spacecraft have obtained lunar data and samples, and American astronauts have orbited, landed upon, and roved upon the Moon.

The Earth and Moon now make one revolution about their barycenter, or common center of mass (a point about 4670 km from the Earth's center), in 27d 7h 43m 11.6s. This sidereal period is slowly lengthening, and the distance (now about 60.27 earth radii) between centers of mass is increasing, because of tidal friction in the oceans of the Earth.

The Moon's present orbit is inclined about 5° to the plane of the ecliptic. As a result of differential attraction by the Sun on the Earth-Moon system, the Moon's orbital plane rotates slowly relative to the ecliptic (the line of nodes regresses in an average period of 18.60 years) and the Moon's apogee and perigee rotate slowly in the plane of the orbit (the line of apsides advances in a period of 8.850 years). Looking down on the system from the north, the Moon moves counterclockwise. It travels along its orbit at an average speed of nearly 0.6 mi/s (1 km/s) or about 1 lunar diameter per hour.


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