One celestial object hidden by other or in the shadow of another
Solar eclipse: sun hidden by the moon
Lunar eclipse: moon in earth’s shadow (sun hidden from moon by earth)
Spectacular because moon and sun appear to be the same size from earth
Solar Eclipses The Sun is vanishing! The Sun is going out! The daylight is retreating!
The Modern View The answer lies hidden among the shadows. Earth Moon
Shadow Structure Umbra Penumbra Penumbra
Umbra – region of total shadow
Penumbra – region of partial shadow
Totality lasts only a few minutes!
Why isn’t there a solar eclipse every month?
Inside the Umbra
It gets dark
Birds stop singing
Nature slows down
Solar Eclipse Details Moon What is the phase of the moon? New Moon! South Pole North Pole Sun
Solar Eclipse Images
Total Solar Eclipse
A Total Solar Eclipse from beginning to end
The Diamond Ring
Why not a solar eclipse every month then? Sun Ecliptic Moon Moon’s Orbit Earth 5 o Moon's orbit is tilted about 5 o with respect to the Earth's orbit (ecliptic), so the shadows usually miss!
But, the Moon passes through the ecliptic twice a month. *IF* at new moon - SOLAR ECLIPSE probability.
Annular Solar Eclipse
Partial Solar Eclipse During a total solar eclipse, depending on your location during the event, you might only see part of the Sun’s face blocked because of your observing vantage point.
Moon moves into earth’s shadow…
… and out of it (takes hours!)
A Lunar Eclipse Moon A lunar eclipse occurs when the Earth lies between the Sun and Moon, so that Earth's shadow darkens the Moon. Sun Earth Moon’s Path
This image shows a complete transition during a lunar eclipse. Notice that the phase of the moon is “full.”
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.
Totality Totality Q: Why does the Moon look orange in total lunar eclipses
Totality Totality A: Because the sky on Earth is blue. The Earth’s atmosphere’s air molecules filter out red & orange frequencies by scattering them into Earth’s night side. This “ rest light” illuminates the Moon (weakly).
The Blood Moon 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. Earth’s Atmosphere Sunlight Moon Earth
Lunar Eclipse Types Total Penumbral Eclipse Total Lunar Eclipse Partial Lunar Eclipse Partial Penumbral Eclipse
Daily fluctuations in the ocean levels
Two high and two low tides per day
A result of the difference in gravitational pull from one side of the Earth to the other
The idea behind Tides
There are two tidal bulges, i.e. two high tides per day, because:
Moon pulls water towards it on one side
Earth is pulled towards the Moon, away from the water on the other side
Force of Moon on water (strong) Force of Moon on Earth (weaker) Force of Moon on “back-water” (much weaker)
Spring and Neap Tides
Tides especially pronounced when Sun and Moon “work together”