Download Moon an Elipses

Moon, Moon Phases &
Eclipses
The Moon
Myths about the Moon
The Moon is made of cheese!
There is a Man in the Moon.
The Moon and the Sun chase each other across the sky.
The Moon disappears during certain days of the month.
There are men or other creatures living on the Moon.
The Moon was put in the sky by a person or animal.
The Moon is a living creature or a god.
The Moon controls how we act and how we feel.
During a full moon, some people turn into werewolves.
The Moon is pulled across the sky by a person, animal, or force.
Myths
• Greek goddess Artemis, roman goddess Diana
Myths
• Chinese mythology: Chang’e
• Moon festival
Calendar
• The current standard calendar is solar calendar
(Gregorian calendar) – counting days
• The moon phases have a period of 29.5 days, a good
measure of time
• Lunar calendars – counting days and months
• E.g. Islamic calendar is a lunar calendar
• 29.5 * 12 = 354, 11 days less than 365
• Lunisolar calendar – Chinese calendar, Hebrew calendar
• Adding leap months, with a circle of 19 years
Moon – our closest natural celestial
body neighbor
• The earth’s only natural satellite
• Orbit around the earth is an eclipse
• Average distance from the earth to
the moon is 384,403 kilometers
(238,857 miles) – 30 times the
diameter of the earth
• Diameter of 3,474 km, ¼ of the earth
• Gravity 1/6 of the earth
Moon’s orbit
• The orbit period around the earth – 27.3 days
• The spin period is exactly the same!
• We always see the same side of the moon!
( precisely speaking 59% of the surface during
the whole period of the moon revolution.
Reason: libration)
• The period of Lunar Phase – 29.5 days
• Because of the earth’s revolution in the space
• The orbit plane of the moon is tilted by ~5
degree with respect to the earth’s orbit around
the sun, unlike other planets
Moon’s orbit
• The orbit plane of the moon is tilted by ~5 degree
with respect to the earth’s orbit around the sun,
unlike other planets
Near Side
Far Side
Moon’s surface
Highland
• Maria (sigular mare, ‘sea’ in Latin)
Maria
– Dark areas and were thought to be
seas
– Cover 31% of the near side, but only
2% of the far side
– No water but vast pools of solidified
lava that flowed into basins formed
by comets/metors colliding
– Nomenclature
• Latin terms describing the weather
and abstract concepts
– Smaller dark regions
Crater
• Lacus (Lake)
• Palus (marsh)
• Sinus" (bay)
Highland
Moon’s surface
• Highland
– Lighter color regions, or
called Terrae
– Many are impact basins’ outer
rims
– In contrast to earth, no major
lunar mountains were formed
as a result of tectonic events
– Mountains and mountain
ranges
Maria
–
Crater
Different brightness of the
highlands and maria is because
they are composed of different
rock types
Craters
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Formed when asteroids/comets
hit the lunar surface
Half a million craters with
diameters larger than 1km
Crater counting – to estimate
the age of the lunar surface
The largest crater is South
Pole-Aitken basin, with 2,240
kms in diameter and 13 kms in
depth
Nomenclature:
– Large craters, deceased
famous scientists, artists
– Small craters, common first
names
• Daedalus, 93 km in diameter
• Proposed as a site for a large
radio telescope
Known maria, highlads and craters
The formation of the moon
• Born from the earth - broke off from the earth
by centrifugal forces, and left the pacific ocean
behind
• Captured by the earth’s gravity
• Co-formation with the earth
• Giant impact hypothesis
– An impact of a Mars-sized body collide w/ the protoEarth and ejected materials to orbit around the earth –
the Moon
Explorations of the moon
• Ancient people observed the moon by naked eyes, and wrote
poems and essays, and told myths
• Galileo first observed the moon using an telescope
• The only celestial body the human being has orbited and
landed
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First impact: Luna 2 of Soviet Union in 1959
First far side picture: Luna 3 in 1959
First soft landing: Luna 9 in 1966
First men’s step on the moon: Apollo 11 in 1969
Moon Phases
• Why does the moon change phases?
• Lunar phases are the result of our eyes seeing the
illuminated half of the Moon from different
viewing geometries
• Due to the Moon’s orbital positions
The Moon’s Orbit around the earth
Moon Phases
Complete this
Say, Sun rises at 6am and sets at 6pm
Moon Phase
Moon Rise Time
New Moon
Sunrise/6am
Waxing Crescent
9am
First Quarter
12pm
Waxing Gibbous
3pm
Full Moon
6pm
Waning Gibbous
9pm
Third Quarter
12am
Waning Crescent
3am
When new moon occurs, what is the phase of the earth
if you stand on the moon?
Full earth!
The earth always has an opposite phase to the moon.
Eclipses
• Have you seen eclipses?
• What are eclipses in nature?
– One celestial object casts its shadow on the
other one
Solar Eclipses
• Sun – the shadow of the moon on the earth
Total solar eclipse in 1999
A – total eclipse
B – annular eclipse
C – partial eclipse
Lunar Eclipses
• Moon – the shadow of the earth on the
moon
Lunar Eclipse
What’s the moon phase when a solar eclipse occurs?
New Moon
What’s the moon phase when a lunar eclipse occurs?
Full Moon
Why aren’t there solar eclipses and lunar eclipses on EVERY
new moon and full moon?
Two conditions must be satisfied for an
eclipse to occur
1. The nodes of the moon’s orbit must be
nearly aligned with the Sun and the
Earth
2. The phase of the moon must be new or
full
Eclipses Cycle
• Every year there are at least two lunar eclipses
• Lunar eclipses and solar eclipses always come in
pairs
• Lunar eclipses can be seen everywhere on the
earth, but the solar eclipses may only be seen on
part of the earth
Discussion Board
• Research and Describe perigee and apogee.
• Blue Moon
Solar eclipses