Moon

The Earth's moon. Galileo observed the moon through a telescope and thought that the dark areas were seas. This is why some areas of the Moon are named as seas.

A view of the Apollo 11 lunar module "Eagle" as it returned from the surface of the moon to dock with the command module "Columbia". 21 July 1969

Click on an item to paste into clipboard or use clipboard symbol at end to clipboard all values

Mass	7.3483E+22	kg	Clip
Equatorial diameter	3474800	m	Clip
Mean orbital radius	384400000	m	Clip
Orbital period	27.32166d	y=Earth year, d=Earth day	Clip
Gravity at equator	1.62	ms-2	Clip
Mean orbital velocity	1030	ms-1	Clip

paste all data into clipboard

Waning Moon

The moon between full and new when its visible part is decreasing.

Historical Notes

470BC Anaxagoras suggests that the Sun, Moon and stars are composed from the same matter as Earth.

450BC Anaxagoras proposes that the Moon shines with the light of the Sun and from this was able to explain the eclipses.

330BC Pytheas proposed that tides are caused by the Moon.

1504 Christopher Columbus correctly predicts the total eclipse of the moon.

1964 Unmanned U.S. spacecraft transmitted television pictures of the moon before hitting the surface.

1966 The first unmanned soft landing on the moon (Soviet Union).

1968 First manned flight around the moon is made by Frank Borman, James Lovell and William Anders in Apollo 8.

1969 Apollo 11 crew make the first human landing on the moon. Neil Armstrong steps on the moon.

1972 Eugene Cernan and Jack Schmitt in Appolo 17 are the last to land on the Moon.

See also: Earth, Earthlight, Halo, Metonic Calendar, Selenoid, Selenology, Sun.

Weblinks:

NASA Photographic Library Photographs from NASA available for viewing and download.

Phases of the Moon US Naval Observatory Astronomical Applications Department.

Apollo Image Archive A digital archive of all the original Apollo flight films.