Download Moon Power Point

THE MOON
Definitions
• Year – time that a planet takes to go
around the sun once.
• Revolution – motion of a body
orbiting another body in space
• Prograde rotation –
counterclockwise spin of a planet or
moon as seen from above the
planet’s North Pole (rotates in the
same directions as the sun’s
rotation), EARTH
• Retrograde rotation – the clockwise
spin of a planet or moon as seen from
above the planet’s North Pole. Venus,
Uranus
• Greenhouse effect – carbon dioxide
traps thermal energy from sunlight,
causes surface temperatures to
increase
• Gas Giants – planets that have deep,
massive atmospheres rather than hard
rocky surfaces like those of the inner
planets
• Satellites – natural or artificial
bodies that revolve around larger
bodies such as planets. All planets,
except MERCURY and VENUS have
satellites.
• Phases – change in the sunlit area of
one celestial body as seen from
another celestial body.
• Eclipse – an event in which the
shadow of one celestial body falls
on another
Measuring Distance in Space
• Astronomical Unit – the average
distance between the Earth and the
Sun
• Using the speed of light – light
travels at about 300,000 km/s in
space
• In 1 second, light travels 300,000
km.
• In 1 minute, light travels nearly
18,000,000 km – LIGHT MINUTE
Astronomical Unit – the average
distance between the Earth and
the Sun
Solar System Divided into two
main parts
• Inner solar system contains
four planets that are closest to
the sun (Mercury, Venus, Earth
and Mars)
• More closely spaced
• Terrestrial planets
• Dense and rocky
Inner Planets
• Outer system contains 4 planets
farthest from the sun. (Jupiter,
Saturn, Uranus, Neptune)
• Composed mostly of gas
• GAS GIANTS
• Pluto is now considered a
satellite of Neptune – It’s not
composed of gas – is small, dense
and rocky
The Outer Planets
Why did the Earth have such
good fortune?
• It’s just at the right distance from
the Sun
• Warm enough to keep most of its
water from freezing
• Cool enough to keep its water from
boiling away
• Liquid water is a vital part – all
living things depend on
The surface of bodies that
have no atmosphere
preserve a record of
almost all of the impacts
that the bodies have had.
LUNAR ORIGIN
3 possible explanations for the
moon’s formation:
1. Moon was a separate body captured
by Earth’s gravity
2. Moon formed at the same time and
from the same materials as the
Earth
3. The newly formed Earth was
spinning so fast that a piece flew
off and became the moon
• When a moon rock was brought
back, scientist found that the
composition of moon was similar to
that of the Earth’s mantle.
• CURRENT THEORY – large, Marssized object collided with Earth
while Earth was still forming.
Collision was so violent that part of
the Earth’s mantle was blasted into
orbit around Earth to form the
moon.
Origin of the moon
IMPACT
EJECTION
FORMATION
Basic Moon Stats
• 384,000 Km away
• 3476 km in diameter
(1/4 of Earth)
• Density 3.3 g/cc
• Mass is 1/80 of
Earth
• Gravity is 1/6 of
Earth
Basic Moon Stats
• Temp varies from -175 C to 100
C!!!
• Age is similar to Earth
• No Atmosphere or water
• Revolves once every 27.3 days
• Rotates once every 27.3 days
• Blue Moon – 2 full moons in one
month
(1)
Exploration of the Moon
• Apollo Moon
Landing Project
• Neil Armstrong
walked on moon
in 1969
• Ended in 1972
• Humans haven’t
been back since
• Perigee-moon is closest to Earth
• Apogee-moon is furthest from
Earth
Perigee
Apogee
356410 km
406700 km
5% Variation in distance from Earth!
PHASES OF THE MOON
• The different phases are due to
its changing position
• WAXING – sunlit fraction that
we see is getting BIGGER (lit on
the RIGHT)
• WANING – sunlit fraction that
we see is getting SMALLER (lit
on the LEFT)
PHASES OF THE MOON
PHASES OF THE MOON
• Total amount of sunlight that
the moon gets remains the same
– Half the moon is always in
sunlight
• Because the moon’s period of
rotation is the same as its
period of revolution – on Earth
you always see the same side
of the moon
PHASES OF THE MOON
Does the Moon Rotate?
• We always see
the same side
of the Moon –
it’s rotation
and revolution
are equal
• Synchronous
Rotation
The Moon and The Tides
Neap Tide
• Neap Tide-A weaker than average
tide due to the conflicting
gravitational forces of the sun and
moon
Spring Tide
• Spring Tide-A stronger than
average tide due to the
gravitational forces of the sun and
moon working together (3)
ECLIPSES
• When the shadow of one celestial body
falls on another, an eclipse occurs.
SOLAR ECLIPSE
• SOLAR ECLIPSE – happens
when the moon comes between
Earth and the sun and the
SHADOW OF THE MOON
FALLS ON PART OF THE
EARTH
• Only occurs during NEW MOON
PHASE
SOLAR ECLIPSE - we see some
portion of the Sun's disk covered
or 'eclipsed' by the Moon.
Solar Eclipse
Solar Eclipse
• During a total solar
eclipse, the disk of the
moon completely covers
the disk of the sun.
Total Solar Eclipse
LUNAR ECLIPSE
• Happens when earth comes between
the sun and the moon and THE
SHADOW OF EARTH FALLS ON
THE MOON
• Only occurs during FULL MOON
PHASE
• Because the moon’s orbit is
elliptical, the distance between
the moon and the Earth changes
Lunar Eclipse
The shadow of the Earth falls on the moon
Which gives the moon a reddish tint
Lunar Eclipse
Annular Eclipse – type of solar
eclipse
• During an annular eclipse,
the disk of the moon does
not completely cover the sun
• During a total solar eclipse
the disk of the moon does
completely cover the sun –
only the corona is visible
annular eclipse
Total Solar Eclipse
Orbit of the Moon
• The moon’s orbit around
Earth is tilted about 5º
relative to the orbit of
Earth.
• This is why there aren’t
solar and lunar eclipses
every month
Tilt of the Moon’s Orbit
• Tilt is enough to place the
moon out of Earth’s
shadow for most full
moons and Earth out of
the moon’s shadow for
most new moons.