Complicated by Earth's rotation continents stopping water flow variable ocean depths etc... Eclipses Introduction Sun and Moon have same apparent size in the sky (~ half a degree) Eclipse: when any part of the Earth or Moon enters the shadow of the other Earth in Moon's shadow: solar eclipse Moon in Earth's shadow: lunar eclipse Moon's orbit is tilted 5 to plane of Sun's orbit (ecliptic) usually Moon is above or below Sun when Moon and Sun's orbits cross (twice a year) eclipse is possible Solar Eclipse Apparent size of Sun and Moon varies with time if Moon is slightly nearer to Sun and completely hides it solar eclipse results small part of Earth will be in Moon umbra -- total darkness partial eclipse if in Moon's penumbra Moon moves East at 1500 km/hr -- defines ``eclipse path'' 3000 km around this is partial eclipse zone eclipse never lasts more than 7 minutes Lunar Eclipses Earth's shadow crosses Moon (thus during full Moon) visible to all who see the Moon, so more frequent from any one spot on Earth Total eclipse if Moon is in Earth's umbra;
(Moon's orbit; is tilted; 5) (Moon; hides; it) Context(Moon hides,List([558, 609))):(solar eclipse results; will be; in Moon umbra) (3000 km around this; is; partial eclipse zone eclipse never lasts more than 7 minutes Lunar Eclipses Earth's shadow crosses Moon (thus during full Moon) visible to all) Context(3000 km around this is,List([791, 813))):(partial eclipse zone eclipse; never lasts; visible to all) (Earth's rotation continents; stopping etc; water flow variable ocean depths) (Moon; is; above or below Sun; T:usually) (Moon; is; slightly nearer to Sun) (Eclipses Introduction Sun and Moon; have; same apparent size in the sky (~ half a degree) (Moon; is; in Earth's umbra) (Moon's penumbra Moon; moves; East; T:at 1500 km) (any part of the Earth or Moon; enters; the shadow of the other Earth in Moon's shadow) (all; see; the Moon)
Moon hides,List([558, 609)) 3000 km around this is,List([791, 813))
Moon's orbit Moon solar eclipse results 3000 km around this partial eclipse zone eclipse Earth's rotation continents Moon Moon Eclipses Introduction Sun and Moon Moon Moon's penumbra Moon any part of the Earth or Moon all
is tilted hides will be is never lasts stopping etc is is have is moves enters see
5
it
in Moon umbra
partial eclipse zone eclipse never lasts more than 7 minutes Lunar Eclipses Earth's shadow crosses Moon (thus during full Moon) visible to all
visible to all
water flow variable ocean depths
above or below Sun T:usually
slightly nearer to Sun
same apparent size in the sky (~ half a degree
in Earth's umbra
East T:at 1500 km
the shadow of the other Earth in Moon's shadow
the Moon