Transcript The Moon - Cloudfront.net

Chapter 30 – vocabulary Quiz – Define terms
Craters
2. Rays
3. Apogee
4. Perigee
5. Maria
1.
4/6/2016
Essential Question:
Compare the Galilean moons and the rings of
Jupiter with the moons and rings of the other
outer planets



Warm Up : Explain how we ended up with our modern
calendar.
Exit Task: compare the rings of Jupiter to the rings of
Saturn
Homework
• Study for chapter 30 test
4/6/2016
Vocabulary Chapter 30, define & one fact
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Maria
Rilles
Craters
Rays
Apogee
Perigee
Eclipse
Umbra
Penumbra
Solar eclipse
Lunar eclipse
New moon
4/6/2016
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Waxing
Full moon
Waning
Earthshine
Calendars
Day
Month
Solar year
Julian calendar
Leap year
Gregorian calendar
Galilean moons
List the five kinds of lunar
surface features
Highlands composed of light colored rock
 Dark areas called Maria (dark solidified
lava), that reflect little light.
 Rilles are areas that look like river beds
where lava once flowed
 Craters are bowl shaped depressions,
most were formed 4 billion years ago.
 Rays is displaced materials from more
recent impacts that extend radially from
the impact site.

4/6/2016
Describe the interior of the moon




The side of the moon that faces Earth the crust
is 60km thick.
The side away from the Earth is up to 100km
thick.
Beneath the crust is the mantle, which goes to
a depth of 1000 km and probably rich in silica,
magnesium and iron
The moon may have a small iron core with a
radius less than 700 km
4/6/2016
Summarize the four stages in the
development of the moon.


Stage 1
• The giant-impact hypothesis: says that a
Mars sized object struck the earth in the
early history of the solar system. Materials
were ejected from this collision which formed
the moon.
Stage 2
• The moon was covered with an ocean of
molten rock. The densest sinking to the
center to form the core and the lighter rock
forming the crust or outer layers.
4/6/2016
Summarize the four stages in the
development of the moon.


Stage 3
• The moon had cooled enough to form a thick crust
that covered the molten rock. Debris from the
formation of the solar system struck the moon
producing the cratered surface. Some of the
meteorites broke the crust and allowed molten rock
to flow to the surface to form Maria.
Stage 4
• The final stage started 3 billion years ago after the
moon had cooled and the debris from the early solar
system had decreased. All geologic activity has
stopped and meteors now cause a rayed impact. The
moon has remain virtually unchanged for 3 billion
years.
4/6/2016
Describe the orbit of the moon
around the earth.




The moons orbit around the earth is an ellipse.
This means the distance from the earth varies
• when at it’s farthest point it is at apogee
• the closest point is perigee.
The average distance is 384,000 km.
The moon appears to rise and set with the
earth rotation
• but it is really moving 1/29th the distance of
it’s orbit.
• This can be seen in the fact that it will rise
and set 50 minutes later each night.
4/6/2016
Explain why eclipses occur.



An eclipses occurs when a planetary body
passes through the shadow of another.
There are two parts to the shadow
• the inner cone (called the umbra) blocks the
sunlight completely.
• The outer part of the shadow (called the
penumbra) only partially blocks the light.
We see two types of eclipses, a lunar and a
solar
4/6/2016
Explain why eclipses occur.

Solar eclipse
• A solar eclipse is when the moon passes between the
earth and the sun.
• The moons shadow fall upon the earth.
• People within the umbra will see a total eclipse and
those in the penumbra but outside the umbra will
see a partial eclipse.
• Because of the rotation of the earth, a total eclipse
will never last more then 7 minutes.
• Sometimes an eclipse will occur when the moon is at
it’s apogee, this is called an annular eclipse and a
line of sunlight can be seen around the edge of the
moon.
4/6/2016
Explain why eclipses occur.

Lunar eclipse
• This occurs when the moon passes
through the earth’s shadow
• A total eclipse occurs when the moon
passes through the earth’s umbra
• A partial occurs when it passes through
the penumbra.
• They last several hours.
4/6/2016
Describe the phases of the Moon






When the moon is between the sun and earth - new
moon phase.
Next a waxing-crescent phase.
Followed by a quarter moon
Next waxing-gibbous phase
full moon
After this it moves into the waning-gibbous phase and
when it is a quarter or less it is in the waning-crescent
phase.
4/6/2016
4/6/2016
compare the Galilean moons & the
rings of Jupiter with the moons &
rings of the other outer planets
Explain How calendars are based on the
movements of the Earth and the moon






People would track time passage with the phases
of the moon.
In time these were converted into calendars.
There are three main parts days, months, and
years.
A day would measure the passage of one earth
rotation (24 hours).
A month would measure one complete moon
phase (29.5 days)
a year measure the time it takes the earth to
complete one complete orbit around the sun
(365.25 days).
4/6/2016
Explain How calendars are based on the
movements of the Earth and the moon




Problems: a year of 365 days is too short and a
366 day is too long
so there must be a way to account for the ¼ day
in the year.
Second a 29 day month is too short and a 30 day
month is too long, the days of the month must
vary to account for this problem.
Third, the moon orbits the earth between 12 to
13 times in a year, so the number of months can
not correspond to the movements of the earth
and moon and remain accurate.
4/6/2016
Explain How calendars are based on the
movements of the Earth and the moon




The Julian calendar was the first to solve this
problem.
The year was divided into 12 months and eleven
months had 30 or 31 days and February had 29.
Later 1 day was moved to August and the leap
year was added to keep the system balanced.
It did not take into account for the fact that they
had estimated the year 11 minutes longer then it
really is. This calendar lasted over 1500 years.
4/6/2016
Explain How calendars are based on the
movements of the Earth and the moon




BY 1580 the calendar was about 10 days ahead
of the seasons.
To solve the problem Pope Gregory XIII ordered
ten days be dropped from October in 1582 and
that the Julian needed to be corrected.
The solution was that every 400 years the
calendar needed to be 3 days shorter, so if the
leap year ends in 00 and is not divisible by 400
there is no leap and you must wait 4 years for
the next leap year to occur.
The Gregorian is accurate to within 26 seconds
and only needs to be adjusted every 3000 years.
4/6/2016
Compare the characteristics of
the two moons of Mars






Moons of Mars: Phobos and Deimos
Phobos completes an orbit in 7 hours and 40
minutes
Deimos completes an orbit in about 30 hours
Irregular in shape: Phobos is 27km by 19km,
Deimos is 15km by 11km
Phobos has an 8km crater on it, both have
many craters suggesting they are old.
Both are smaller then a medium sized crater on
our moon
4/6/2016
Compare the Galilean moons and the rings of Jupiter
with the moons and rings of the other outer planets.
Jupiter has rings that are 6,400
km wide and less than 30 km
thick
 4 Galilean moons; IO, Europa,
Ganymede and Callisto.

4/6/2016
Compare the Galilean moons and the rings of Jupiter
with the moons and rings of the other outer planets.
All viewed by Galileo in 1610
 IO; is the closet to Jupiter, has active
volcanoes of sulfur, sulfur dioxide
atmosphere, giant iron core with a
magnetic field and red, orange and
yellow in color
 Europa; second closest, covered in ice
100 km thick, rock core and possible
water

4/6/2016
Compare the Galilean moons and the rings of Jupiter
with the moons and rings of the other outer planets.
Ganymede; third from Jupiter, low
density, largest moon in the solar
system, made of rock and ice, has valleys
and ridges, and has a magnetic field.
 Callisto; farthest from Jupiter, similar to
Ganymede in size, density and
composition, surface is the most cratered
in the solar system.

4/6/2016
Compare the Galilean moons and the rings of Jupiter
with the moons and rings of the other outer planets.
Saturn; Rings are larger and brighter
then any other planet in solar system.
 Each ring is divided into 100’s of ringlets.
 Size of rings 64,000 km wide and 200
meters thick
 Has 18 moons most small and icy, has 5
large moons and Titan is largest at 5,000
km diameter.
 Titan has a thick nitrogen atmosphere.

4/6/2016
Compare the Galilean moons and the rings of Jupiter with
the moons and rings of the other outer planets.



Uranus has 20 small moons: the four largest
are Oberon, Titania, Umbriel, and Ariel –
discovered in mid 1800’s. Miranda found in
1948 and the rest after 1985 by Voyager 2,
Has 11 small rings
Neptune has 8 moons: Triton and Nereid are
largest, Triton has a retrograde orbit. Has a
thin set of rings
Pluto has one moon Charon and completes one
orbit in 6.4 days, always over the same spot.
4/6/2016
Jupiter number of moons 63
 Saturn number of moons 60
 Uranus number of moons 27
 Neptune number of moons 13
 Pluto number of moons 3

4/6/2016