Transcript Eclipse
Eclipses A penny will hide the biggest star in the universe if you hold it close enough to your eye. -- Samuel Grafton Solar Eclipses The Sun is vanishing! The Sun is going out! The daylight is retreating! Bad Omens All! The Gods are MAD! The Moon is just close enough, and just big enough, to block our view of the sun = SOLAR ECLIPSE. Only the sun’s CORONA is visible If the Moon was A) smaller, or B) farther from us, would we experience TOTAL solar eclipses? ANNULAR ECLIPSE – when moon is farthest from Earth – some sun visible The Modern View The answer lies hidden among the shadows. Moon Earth Shadow Structure Penumbra Umbra Penumbra Solar Eclipse Details North Pole Sun Moon What is the phase of the moon? New Moon! South Pole Total Solar Eclipse A Total Solar Eclipse from beginning to end Why not a solar eclipse every month then? Moon Earth 5o Ecliptic Sun Moon’s Orbit Moon's orbit is tilted about 5o with respect to the Earth's orbit (ecliptic), so the shadows usually miss! But, the Moon passes through the ecliptic, and is found along the line of nodes, twice a month. *IF* at new moon - SOLAR ECLIPSE probability. *IF* at FULL moon - LUNAR ECLIPSE probability. If line of nodes points to the sun during new or full moon phases; ECPLIPSE!!! A Lunar Eclipse Sun A lunar eclipse occurs when the Earth lies between the Sun and Moon, so that Earth's shadow darkens the Moon. Earth Moon Moon’s Path The moon becomes a blood red color during a total lunar eclipse. No wonder that ancient cultures feared the appearance of the moon during a lunar eclipse. The Blood Moon Moon Earth Sunlight Earth’s Atmosphere The moon often does not totally disappear during a total lunar eclipse. Instead it can be seen as a very dark red color because of the refraction of sunlight through the Earth's atmosphere. The End