Download A Tour Of The Solar System

A Tour Of The Solar System
Galaxies
Galaxies are huge regions of space that
contain the stars, planets, and other
astronomical features
They can have many shapes
Spiral
Elliptical
Irregular
Our galaxy is known as the milky way
galaxy
Http://www.astro.Princeton.edu/~frei/G
cat_htm/cat_ims.htm
Milky Way Galaxy
80,000 light years
across
Spiral shaped with 4
arms
We are located in
the Orion arm
Nearest neighbor is
Andromeda (2.2
Million light years)
Solar System
Origin of the Solar System
The solar system
began as nothing
more than dust
Gravity caused the
dust to condense
and spin
As the cloud gets
hotter and denser
fusion takes place
The fusion results in
the birth of a star
Proto – Planetary Disc
As our star, the sun, is
being formed it is
surrounded by a disc
of debris and gas
These particles interact
and accumulate to
form the plants
When the sun forms it
emits solar wind
This wind pushes
lighter material
outward (the gases)
The Sun
One of more than
100 billion in our
galaxy
Rotates about the
nucleus at about
137 miles/sec
Takes about 200
million years to
complete a rotation
Accounts for 99.8%
of the mass of our
solar system
The Sun Cont.
The sun is the center of the solar
system
Because it is so massive all of the
planets are captured in its gravity field
and orbit it
Composed of 75% hydrogen and 25%
helium
The core is about 15.6 million Kelvin
The surface, photosphere, is about
5800 K
The Planets
There are 9 planets that orbit the sun
The orbit is in an elliptical path
The plane along which the planets orbit is
known as the ecliptic
The Earth
3rd rock from the sun
(5th largest)
149,600,000 km from
the sun
Rotation: 23 hr 56 min
Orbit: 365.26 days
Mass: 5.97 x 1024 kg
Gravity: 1.0
Obliquity: 23.5 degrees
Formation of the Earth
The earth was formed
from accreted particles
in the proto-planetary
disc about 4.6 Ga
As the material was
accreted it began to
differentiate
(responsible for
internal layering)
The denser material
sank towards the
center (iron core)
Lighter material rose
towards the top (crust)
Seasons
The earth spins
about an axis that is
at an angle of 23
degrees with the
ecliptic
This angle causes
different regions of
the earth to
experience variable
amounts of sunlight
throughout the year
Earth’s Magnetic Field
The liquid outer core of the
earth is in a state of
convection
This convection is
responsible for a magnetic
field about the earth
The magnetic field of the
earth resembles that of a
bar magnet
Solar wind from the sun
interacts with the magnetic
field to create the northern
lights
Aurora Borealis
Earth’s Oceans and Atmosphere
The earth is
distinguishable from
the other terrestrial
planets because of
its surface water
Water accounts for
71% of the earth’s
surface
The earth’s
atmosphere is 77%
nitrogen and 21%
oxygen
The atmosphere
helps block out
harmful rays and
maintains the
surface temperature
The Moon
Earth’s only satellite
384,000 km from earth
1738 km radius
Mass: 0.07 x 1024 kg
Gravity: 0.16
Orbit: 27.32 days
Rotation: 27.32 days
4.4 Ga old
No:
Magnetic field
Oceans
Plate tectonics
Atmosphere
Moon Formation
During the earth’s
formation a large object
collided with the earth
The ejected material is
the moon
Differentiation was
already in process so
the moon is composed
of the lighter external
materials (largely
basalts)
Moon’s Surface
The surface of the
moon is composed
largely of basalts
The major surface
feature are craters
from meteoroid
impacts
Evidence of lava
flows exist for
impact craters
greater than 100 km
The Moon’s Rotation
The rotation of the
moon is the same as
the orbit.
This implies that we
always see the same
side of the moon.
The phase of the
moon that we see
depends on the
moon’s location
relative to the sun
Mercury
Closest planet to the
sun (58 million km)
Second smallest planet
2,439 km radius
Mass: .33 x 1024 kg
Gravity: 0.38
Orbit: 87.96 days
Rotation: 58.65 days
Mercury Rotation
Mercury rotates 1.5
times per each orbit
This 3:2 ratio causes
the mercury day to
be extremely long
(176 earth days)
During the day the
surface can get as
hot as 700 K
During the night the
surface cools to 100
K
Mercury Surface
Dominated by craters
and basins
Cratering took place
early (ended 3.8 Ga)
Largest basin: Caloris
Planitia
1300 km diameter
Plains regions also exist
Evidence of lava flows
Scarps are other
surface features
Evidence of contraction
Mercury’s Interior
Despite its small size, mercury is very dense
Implies internal composition must be iron
Presence of a magnetic field (1% of earth’s)
confirmed this
To account for magnetic field and density,
mercury is 70% metal and 30% silicates
Believed that a large impact after
differentiation ejected most of the silicate
material
Water / Atmosphere
No surface water
exist on the surface
of mercury
Potentially ice
located in craters
that see little sun
(polar regions)
Possesses a thin
atmosphere
Atmosphere is
surface material
lifted by solar wind
interaction
Venus
2nd planet from the
sun (108 million km)
Radius: 6,052 km
Mass: 4.87 x 1024 kg
Gravity: 0.76
Orbit: 224.7 days
Rotation: 243 days
Atmosphere
Very thick cloud cover
Atmosphere composed mostly of carbon
dioxide
Clouds composed of sulfuric acid
Effect is a runaway greenhouse
Surface pressure: 90 atm (the same as
1 km depth in earth’s oceans)
Surface temperature: 700 K
Venusian Surface
Very dry
Young (500 my)
Mostly lava plains
Two regions of
major relief
Ishtar terra (polar)
Aphrodite terra
(equatorial)
Few impact craters
Volcanic features
Venus Interior
Venus is very similar
to earth in size,
mass, and distance
Implies similar
interior structure
The core of Venus is
still hot from
formation and
radioactive materials
Implies the mantle
convects
Plate Tectonics?
Although Venus is
currently inactive,
did plate tectonics
exist in the past?
Young surface age
believed to be result
of global overturn.
The overturn marks
the transition from a
mobile lithosphere
to a stagnant
lithosphere.
Venus Rotation
The obliquity of Venus is nearly 180 degrees.
The effect of this is a retrograde rotation.
On Venus it would appear as if the sun rose
in west and sat in the east.
Mars
4th planet from the
sun (228 million km)
Radius: 3393 km
Mass: 0.64 x 1024 kg
Gravity: 0.39
Orbit: 686.98 days
Rotation: 24 hrs 37
min
Mar’s Rotation / Atmosphere
Mars has an axial tilt
of 25.
Orbital period is
nearly twice that of
the earth’s so
seasons are nearly
twice as long.
Tilt and highly
elliptical orbit results
in temperature
variations from
140 K to 300 K.
The atmosphere of
mars is very thin
Composed primarily
of CO2
Seasonal dust
storms results in a
lot of dust in the
atmosphere
Small % of water in
atmosphere can
produce clouds
Martian Atmosphere
Martian Surface
Features include:
Shield volcanoes:
• Olympus Mons (24
km high and 550 km
wide)
Patera:
• Shield volcanoes that
do not rise very high
but extend for great
distances.
Channels:
• Valles Marineris (3000
km long, 8 km deep,
and 600 km wide)
Southern
hemisphere heavily
cratered while
northern
hemisphere is not
Inactive
Water?
Mars contains polar
caps
Channels suggest
water at some point
in the martian
history
Current hypothesis:
Water is located
beneath the surface
(much like
permafrost on earth)
Martian Interior
Smaller so had
longer time to cool
Less dense so core
probably has sulfer
and iron
composition
Core is 1700 km
thick
Mantle: 1300 km
Crust: 80 km
Is There Life on Mars?
Popular notion since
Lowell
Believed that seasonal
color changes were
evidence of vegetation
and channels were
man made
Recent findings
indicate some
biological activity
Moons Of Mars
Two moons: Deimos and Phobos
Both carbon rich but low density suggest both contain ice
as well
Probably astroids captured by mars gravity
Deimos smallest moon in solar system (6.3 km radius)
Phobos: 11 km radius but only 6000 km above surface
Jupiter
5th planet from the
sun (778.3 million
km)
Radius: 71,398 km
Mass: 1900 x 1024
kg
Gravity: 2.74
Orbit: 4,333 days
Rotation: 9 hrs 50.5
min
Jupiter Composition
Likely to have a rocky core (10 - 15 x
the mass of the earth)
Above the core there exist liquid
metallic hydrogen
Only exist at pressures > 4 million bars
Consist of ionized protons and electrons
(source of magnetic field)
Outermost layer is regular hydrogen
and helium
We actually observe the clouds of
Jupiter
Jupiter’s Clouds
Variable composition
consisting of:
Ammonia ice
Ammonia hydrosulfide
Water and ice
Confined to bands of
latitude that rotate in
opposite directions
Most prominent feature
is the GRS
High pressure zone (rises
higher than surrounding
clouds)
Jupiter’s Rings
Voyager discovered in
1971
Contains no ice
Very thin and dark
Composed of rocky
material probably from
the inner four moons
Constantly replenished
since atmospheric and
magnetic field deplete
them
Jupiter’s Moons
At least 16
4 largest (Galilean):
Callisto
Io
Ganymede
Europa
4 inner moons:
Thebe
Metis
Andrastea
Amalthea
Io
It is the center of a tug-a-war between
Ganymede, Europa, and Jupiter
The effect is intense tidal volcanic activity
Surface temperature is low (-143 C)
Has a solid core surrounded by a rocky shell
of silicate? Composition
Europa
Europa consist of a metallic core, a silicate
rock layer, and water.
The outer ice shell of Europa is crisscrossed
by dark bands.
Beneath the ice shell there is potentially large
oceans.
Water exist because of tidal heating.
Saturn
6th planet from the
sun (1427 million
km)
Radius: 60,000 km
Mass: 569 x 1024 kg
Gravity: 1.17
Orbit: 10,579 days
Rotation: 10 hrs 14
min
Saturn Composition
Saturn’s interior is similar to Jupiter’s.
Rocky core, metallic hydrogen, hydrogen,
helium, trace elements
Density less than that of water
Also possesses cloud cover
Clouds trapped in bands of latitude that
rotate at variable speeds
Fastest at the equator
Ring System of Saturn
Ring System of Saturn
Most interesting feature
Very thin (1.5 km thick) despite large
diameter (250,000 km)
Composition is largely ice and rocky
particles coated with ice
Broken into different regions
Origin unknown but must have some
mechanism to replinish
Resonance of moons
Moons of Saturn
18 to date
All have densities less than 2 gm/cm3
30 – 40% rock
60 – 70% ice
Most interact with one another to
produce stable and synchronous orbits
Titan is by far the largest with a radius
of 2575 km
Once believed to be bigger but enormous
atmosphere threw off calculations
Uranus
7th planet from the
sun (2871 million
km)
Radius: 25,559 km
Mass: 87 x 1024 kg
Gravity: 0.94
Orbit: 30,685 days
Rotation: 17 hrs 14
min
Neptune
8th planet from the
sun (4497 million
km)
Radius: 24,800 km
Mass: 103 x 1024 kg
Gravity: 1.15
Orbit: 60,188 days
Rotation: 16 hrs 3
min
Composition
Small rocky cores (3% of their mass)
Thick layer of rock and ice (85% of
their mass)
Most likely in a liquid state (mud)
Atmosphere of hydrogen, helium, and
trace materials
Similar to Jupiter and Saturn without
the liquid metallic hydrogen
Atmosphere
The striking blue color of
these two planets is due to
methane gas
Methane absorbs red light
and reflects blue
Majority of the atmosphere
is hydrogen and helium
Cloud features are more
prominent on Neptune
Neptune once contained
GDS (half the size of the
GRS)
Axial Tilt
Neptune: 29; Uranus: 98
As a result both planets experience seasons
On Uranus the polar regions receive more sunlight
yet equatorial regions are hotter
Lack of storms on Uranus as compared to Jupiter,
Saturn, and Neptune believed to be b/c of orientation
Rings
Both planets
possess rings
Like Jupiter they are
dark (charcoal color)
Compositon is
unknown
Uranus:
11 distinct regions
Neptune:
4 distinct regions
Uranus Satellites
Contains the most
moons (24)
Named after the
writings of
Shakespeare and
pope
3 classes:
11 small dark inner
ones
5 large ones
Outer new ones
Largest is Titania
(789 km)
Neptune Satellites
8 known moons
Largest of which is
Trition (1350 km)
Naiad
Thalassa
Despina
Galatea
Larissa
Proteus
Trition
Nereid
Pluto
9th planet from the
sun (5913 million
km)
Radius: 1,140 km
Mass: 0.01 x 1024 kg
Gravity: 0.03
Orbit: 90,700 days
Rotation: 6.387 days
Orbit
The orbit of Pluto is
very eccentric
During 20 of its 249
year orbit it is closer
to the sun than
Neptune
Pluto and Charon
have the same
rotation period
Composition
Average density is 1.8 – 2.1 g/cm3
Implies 50 – 75% rock
Charon: 1.2 – 1.3 g/cm3
Icy surface composed of:
98% nitrogen
Traces of methane and carbon monoxide
Atmosphere is thin, constantly freezes,
and falls to the surface
Asteroids and Comets
Believed to be remnants of primordial planets
that were destroyed or never formed.
Therefore, they provide detailed information
about past conditions.
Believed to originate in two locations.
Asteroid belt and Kuiper belt, respectively.
Compositions
Asteroids:
C-type: (75%) same
composition as sun
minus hydrogen and
helium
S-type: (17%)
nickel-iron mixed
with iron and
magnesium silicates
M-type: (8%) pure
nickel-iron
Comets:
Mixture of nonvolatile grains and
frozen gases
Web Sources
Amazing space web based activities
Interactive games and lessons
Http://amazing-space.stsci.edu/
BrainPop
Great movie
Http://www.brainpop.Com/science/space/solarsystem/
Build a solar system
How to build a scaled solar system
Http://www.exploratorium.edu/ronh/solar_system/
NASA’s Observatorium
Games
Http://observe.ivv.nasa.Gov/nasa/fun/fun_index.shtml.Html
Space and astronomy
Lessons
http://www.athena.ivv.nasa.gov/curric/space/
Web Sources
Galaxy Catalogue
Images of various galaxies
http://www.astro.princeton.edu/~frei/Gcat_htm/cat_ims.htm
Nine Planets
Lessons on the nine planets
http://www.seds.org/nineplanets/nineplanets/nineplanets.html
Seasons
Experiment to show cause of seasons
http://faldo.atmos.uiuc.edu/w_unit/LESSONS/seasons.html
Virtual Solar System
Lessons
http://freespace.virginnet.co.uk/solar.system/index.html
Views of the Solar System
Bio and pictures of the planets
http://www.hawastsoc.org/solar/eng/homepage.htm