The Sun
Basic Info
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A medium sized star at the center of our solar system
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Contains 99.86% of the Solar System’s total mass
•
About 4.5-5 billion years old (middle aged)
Composition of the Sun
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Mostly Hydrogen and Helium
•
Processes in the sun fuse light elements into heavier
elements through fusion
•
The ionized gas in the Sun is held together by gravitational
attraction.
•
Internal temperature of the Sun reaches 16 million Kelvin
degrees.
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A photon of light takes about 10 million years to escape from the dense core to reach the surface of the Sun.
And after that, it takes 8 minutes 20 seconds to travel to your eye on Earth.
Parts of the Sun
•
The Sun’s surface, or photosphere, is the visible light.
•
Beyond the photosphere is the chromosphere, which appears during total
solar eclipses as a reddish rim.
•
Extending outwards from the chromosphere is the corona, which forms
the solar wind that sweeps charged particles to the edge of the solar
system
Mercury
Location
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Closest Planet to the Sun
•
Can only be seen from Earth during Sunrise/Sunset due to its proximity to the sun
Motion of Mercury
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Length of rotation on axis- 59 days
•
Length of revolution around sun- 88 days
•
It takes Mercury 2 revolutions to completes 3 rotations on its axis
(On other words, it takes 2 years to make 3 days)
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The orbit of Mercury is an elongated ellipse, but it does not go
back to exactly where it was before, it returns slightly ahead of
where it began
Temperature Range
•
Of all the planets, Mercury has the greatest Temperature Range between night and day!
•
Max
430 degrees Celsius
•
Min
-170 degrees Celsius
Composition
•
Extremely Dense (5.4 x water)
•
Composed of mostly metals
•
Iron and Nickel core
•
Rocky outer layer with a brittle cracked crust
Atmosphere
•
Extremely thin atmosphere- very small amounts of Sodium (Na) and other gases
•
Most gases escaped early on in Mercury’s history because the gases became highly excited by heat from the sun
and were not able to be contained by Mercury’s weak gravitational pull and thin atmosphere
Interesting Facts
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Most highly cratered surface due to continuous collisions with asteroids that are drawn into the sun’s gravity
•
Scientists suspect frozen water (H20) may be trapped deep in the some craters at the poles which never get
sunlight
Study of Mercury:

In 1973, Mariner 10 was launched to make multiple flyby encounters of Venus and Mercury. Mariner 10
provided the first detailed data of Mercury, mapping 100% of the surface.

Mapped recently by the Messenger Mission from NASA
o
NASA’s 7th Discovery Program Mission
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Launched 2004
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Fly by of Mercury in 2008
o
Mission complete 2013
Data from Messenger
Venus
Location

2nd Closest Planet to the Sun

Can only be seen from Earth during Sunrise/Sunset due to its proximity to the sun
Motion of Venus
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Length of rotation on axis- 243 days
•
Length of revolution around sun- 225 Earth days
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Its day is longer than its year!
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Rotates East to West, known as Retrograde Motion, the opposite of most other planets
•
In other words, if you were on Venus, the sun would rise in the West and set in the East (the
opposite of Earth.)
Temperature Range
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Max
500 degrees C
•
Min
-32 degrees C
Composition
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Very dense (5.2 x water)
•
Composition similar to Earth with a metal core, liquid rock mantle and a
solid outer rock crust
•
Rocky, dusty, and waterless
•
Geography includes: Volcanoes, Mountains, Canyons, Plains, and huge
hardened lava flows
Atmosphere
•
Very Hostile Conditions
•
Constant cloud cover, no sunny days!
•
Atmospheric pressure is 90 times greater than Earth, enough to crush you
•
Atmosphere composed of Carbon Dioxide (CO2) and Sulfuric acid, not
breathable
•
Green House Effect makes the surface very hot!
Green House Effect on Venus

Venus is closer to the sun than the Earth

Therefore it receives more solar energy

Surface of Venus becomes very hot

Heat is reflected off the surface, but not allowed to travel
into space due to cloud cover.

Carbon dioxide (CO2) cloud cover traps the energy of the
sun

Surface reaches 460 degrees Celsius!!
Interesting Facts
•
Extremely bright object in sky
•
Often called the Evening Star or Morning Star because it can only be seen
at sunset/sunrise
•
From our perspective, Venus exhibits phase changes, much like our moon
Why can we only see Mercury and Venus during sunset and sunrise?
•
In order to view Mercury and Venus from Earth, we must look
inward toward the sun (as opposed as outward into the darkness
of space)
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The only time we can see that direction is during the day
•
During mid-day, the sun is too bright and “whites-out” our view of
these planets, making sunrise/set the only time they are
viewable!
Earth
Location


Third planet from the sun
In the ‘Goldilocks Zone’ -perfect temperature for liquid water
Motion of Earth


Length of rotation- 24 hours = 1 day
Length of revolution- 365 days = 1 year
Temperature Range


-90 degrees Celcius
60 degrees Celcius
Composition




Iron and Nickel core, semisolid mantle, brittle outer
crust
The most dense planet! (5.5 x water)
Wide variety of geography created by plate
tectonics
Earthquakes and Volcanoes
Atmosphere



Composed of Nitrogen, Oxygen, other Elements
5 layers
Outer space begins at 100 km, known as the Karman line
Light (front) side of the Moon
Interesting Facts


Only planet with liquid water
The only planet in our solar system with suitable conditions for development of
life as we currently know it

In geosynchronous orbit with the moon, so we always see the same side
Dark Side of the Moon
(the view we never see))
Moon





Fifth largest moon in the solar system
Almost no atmosphere
A quarter of Earth’s size
Only celestial body on which humans have made a manned landing
Currently widely thought that the moon was created when a Mars sized body collided
with the Earth and the debris recollected and accreted, although a few other theories
exist
Mars
Location
•
Fourth planet from the sun.
Motion of Mars
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Rotation length- 24.5 hours
•
Revolution length- 687 Earth days
•
Mars experiences seasons much like Earth because it is tilted on its axis
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They are much longer due to its more elliptical orbit
Temperature Range
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Max
27 degrees C
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Min
-143 degrees C
Composition
•
Surface composed of Basalt covered in iron oxide
dust
•
Likely iron and sulfur core
•
No Magnetic Field now, but magnetic bands in rocks
are evidence that it once had a rotating metallic
core and plate tectonics
•
Low density (3.3 x water) and small size make the pull of gravity very weak, less than Mercury!
Atmosphere
•
Atmosphere: 95% Carbon dioxide (C02), 3% Nitrogen, 2% trace gasses & no
Oxygen
•
Very thin cloud cover
•
1 % the atmospheric pressure of Earth
•
Prone to dusty wind storms that can cover the entire planet for months at a
time (62 mph winds)
Geography and Features

Only planet in which geographic features can be seen from Earth (with a
telescope)


Once had active Volcanoes. Home to the largest known volcano in the solar
system: Olympus Mons- a young hot spot volcano (It formed in the 1900s.)
In 2012, scientists realized that Mars has a primitive form of Plate Tectonics.

CO2 icecaps exist at both poles

Frozen water discovered in the North pole

Evidence that water once flowed

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River bed and water flows
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Sedimentary Rock formation related to water
Standing pools of liquid water does not currently exist on Mars due to low
surface pressure, low gravity, low air density, and cold temperatures which
lead to rapid freezing or evaporation
Moons- 2 small crater covered

Phobos (13 miles in diameter)

Deimos (7.5 miles in diameter)
Study of Mars:

On January 24, 2014, NASA reported that current studies on Mars by the Curiosity and Opportunity rovers will
now be searching for evidence of ancient life,

Since 6 August 2012, there have been two scientific rovers on the surface of Mars beaming signals back to Earth
(Opportunity and Curiosity of the Mars Science Laboratory mission), and of the Mars Exploration Rover mission

Three orbiters currently surveying the planet: are Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter.

Two orbiters launched in November 2013, Mars Orbiter Mission and MAVEN, are currently on their way to Mars.

To date, no sample return missions have been attempted for Mars, and one attempted return mission for
Mars' moon Phobos (Fobos-Grunt) has failed.
Interesting Facts
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Known as the Red Planet
•
Named for the Roman god of war (because of its red, blood-like color).
Jupiter
Location
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Fifth planet from the Sun
Motion of Jupiter
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Length of rotation-10 hours
•
Length of revolution- 11.87 Earth years
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Most circular orbit
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The fastest rotation (day/night) of all the planets
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If Earth is going 100 mph, Jupiter going 22,000 mph, this fast spinning, creates a bulge at the equator
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It has a non-solid surface so the poles rotate faster than equator
Temperature Range

Core of Jupiter is hotter than the sun. In other words, it radiates more energy than it receives from the sun due
to a process called gravitational compression.

Atmosphere
-110 degrees C

Core
36000 degrees C
Composition
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Thick liquid atmosphere (90% Hydrogen, 10% helium, & traces
of other gases.
•
With relatively tiny solid core (still 10-20 times as massive as the
Earths).
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Clouds made of ammonia ice crystals
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Very close to the composition of the primordial solar nebula
from which the entire solar system was formed.
Atmosphere
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Jupiter is a windy and stormy place
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Wind speeds more than 400 mph
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Some lightning
•
Exhibits Aurora light display!
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Jupiter’s Red Spot
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Oval shaped counter-clockwise storm, the red spot is currently at
the smallest size ever measured since scientists noticed it was
shrinking in the 1930s, 10,250 miles across
Moons of Jupiter
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63 known satellites
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Galileo discovered 4 largest in 1610
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Very different properties
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Io: covered in volcanoes
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Europa: icy crust with liquid water underneath
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Ganymede: largest moon
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Calisto: completely covered in craters
Rings of Jupiter
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Rings are made of dust that was likely ejected from the many satellites
Interesting Facts
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Named Jupiter by the Romans and Zeus by the Greeks; this was the most important of the gods.
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Most Massive Planet
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1/1000th mass of the sun
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2.5 times the mass of all other planets combined
Study of Jupiter:

Many unmanned space missions to Jupiter have occurred and 2 are currently on their way there
(see timeline on right)
Saturn
Location
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Sixth planet from the Sun
Motion of Saturn
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Length of Rotation—11 hours
•
Length of Revolution- 29.7 Earth years
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Has a similar axis tilt to earth- 27 degrees
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As Saturn moves, and tilts, our view of its rings changes
Temperature Range- Saturn is creating twice as much heat as it receives from the sun! Scientists believely that
Saturn’s extremely hot core temperatures are created by gravitational compression due to its large mass and also
theorize that it may be due to friction created when Helium from the atmosphere sinks into Saturn’s interior.

Min-
-173 degrees C (In the atmosphere)

Max-
11,700 degrees C (In the core)
Composition
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Atmosphere contains 2 layers of clouds, mostly Hydrogen and Helium
Methane, and Ammonia
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Rocky Core 10-20 times the size of Earth
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Core surrounded by liquid hydrogen, which is metallic but becomes less so as
it nears the surface, gradually becoming Hydrogen Gas
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Clouds of Ammonia ice crystals
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Less dense than water, it would float!
•
Magnetic field is 578 times more powerful than the
Earth’s
Climate
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Colder than Jupiter
•
Less dramatic clouds and storms than Jupiter
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Extremely high wind speeds, up to 1,000 mph
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The planet gives off about 2.5 times more heat energy than it receives from the Sun.
–
Many astronomers believe that much of Saturn's internal heat comes from energy generated by the
slow sinking of helium through the liquid hydrogen into the planet's interior.
Interesting Facts
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Second largest planet, slightly smaller than Jupiter
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Twice as far from the Sun as Jupiter
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Named for Roman god of agriculture (or Greek god Chronos, father of
Zeus).
Rings of Saturn
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Galileo first noticed them in 1610, but could not explain them at the time
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Rings are composed of chunks of rock, dust, and ice
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More than 30 rings
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In 2009, Astronomers discovered a dust halo around Saturn that extends for
millions of miles around it
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Rings extend hundreds of thousands of kilometers from the planet, but are only 10 m thick (30 feet).
Moons of Saturn
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62 recognized moons, 53 named
•
Difficult to tell apart from the many ice
chunks that revolve as part of Saturn’s
ring system
•
Saturn’s largest moon
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Larger than Earth’s Moon
•
Titan is the only satellite in the Solar System to have an
atmosphere
•
Titan is the only place, besides Earth, of have large amounts
of liquid, has methane/ethane lakes
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Exhibits fog indicating liquid cycling (like earth’s water cycle)
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Has organic compounds, atmosphere, and liquid environment that are ingredients for life, but Titan may be
too cold
Titan
Uranus
Location
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Seventh planet from the Sun
Motion of Uranus
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Length of rotation- 17.9 hours
•
Length of revolution- 84 years
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Uranus is tilted on its side 90 degrees from vertical (so it’s rings look sideways)
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It rotates in a retrograde rotation (backward from the other planets, like Venus)
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So from our perspective, it rotates top to bottom (like a soccer ball)
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Astronomers predict this strange tilt may be the result of the gravitational pull
from a large moon that has since been ejected from Uranus’ orbit or by an impact
from a planet-sized object.
Temperature Range- Uranus has the coldest planetary atmosphere. It does not emit as much heat as the other
outer planets. Even though Neptune is farther away from the sun, Uranus is colder.

Min-
-224.2 degrees C (In the atmosphere)

Max-
11,700 degrees C (In the core)
Composition
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Upper layer of Methane Clouds
•
Lower layer thought to be Water Clouds
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Icy mantle
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Rocky core
•
Blue appearance due to traces of methane in its
atmosphere
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Least massive of the outer planets
Climate
•
Clouds on Uranus were revealed by the Keck II
Telescope
•
Uranus has a dark spot storm just like Jupiter, it’s about
the size of 2/3 the US
Rings
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Two sets of rings discovered; inner rings in 1977 by Voyager Probe
and an outer set in 2003 by Hubble Space Telescope, 2 more
discovered in 2005 by Hubble Space Telescope
•
Has a rare blue ring
•
These faint rings are composed of black dust, particles, and boulder
sized rocks
Moons

27 satellites

Photographed by Voyager 2
Interesting Facts
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Uranus is the first planet discovered since ancient times (1781)
by William Hershel using a telescope.
•
Has 4 times the diameter of Earth
•
Twice as far from the sun as Saturn, 19 x farther than Earth
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Has a very irregular magnetic field
•
Named for the Greek god of the sky.
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It’ tipped on it’s side, likely from a collision with a large celestial
object shortly after its formation
Infrared Hubble Telescope photo of Uranus
and moon Miranda (bottom left) and moon
Puck (faint dot on upper left under ring.)
Neptune
Location
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Eighth planet from the Sun.
Motion of Neptune
•
Length of rotation- 19.1 hours
•
Length of revolution- 164 years
Temperature Range- Like Jupiter and Saturn, Neptune appears to have an internal heat source, and so it radiates more
than twice as much energy as it receives from the Sun.
•
Min-
-221.3 degrees C (In the atmosphere)
•
Max-
-201.15 degrees Celsius (in south pole)
•
South pole is 10 degrees warmer than the rest of planet. This hot spot occurs because Neptune’s south pole
is currently exposed to the Sun.
•
As Neptune continues its journey around the Sun, the position of the poles will reverse. Then the northern
pole will become the warmer one, and the south pole will cool down.
Composition/Atmosphere
•
Composition is 15% Hydrogen and Helium, trace amounts of Methane
•
The atmosphere is 79% hydrogen, 18% helium, and 3% methane
•
Mostly Ices and Rock
•
May not have distinct internal layering, instead more or less uniform in composition.
Climate
•
Has a great storm in the southern hemisphere, The Great Dark Spot, much
like Jupiter
•
Fastest winds in the solar system 1,200 mph
•
Scientists discovered that despite being very cold, Neptune has 1 warm
pole (see infrared image on right)
Interesting Facts
•
Discovered 1846 due to mathematical prediction
•
Named for the Roman god of the Sea.
•
Smaller but denser than Uranus
•
In 2005, astronomers proposed that Uranus and Neptune
may have formed much closer to the Sun before migrating
outwards and swapping places in the process
•
Sometimes, the dwarf planet Pluto, is actually closer to us in orbit
than Neptune, this is due to Pluto’s long elliptical shaped orbit,
which causes it to cross Neptune’s path.
Moons of Neptune
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At least 13 satellites, 1 more waiting to be accepted
•
Some of Neptune’s moons did not form at the time of Neptune’s
formation, but were captured later by gravity. One piece of
evidence for this is that Neptune’s largest moon, Triton, revolves
in the opposite direction of Neptune’s rotation
•
Neptune's largest moon, Triton, was found to be the coldest
known planetary body in the solar system, with a nitrogen ice
"volcano" on its surface.
Rings of Neptune

Has faint rings photographed by Voyager 2
Study of Neptune:


Voyager 2 (1989) is the only human-made object to have flown by Neptune. It discovered five moons, four
rings, and a "Great Dark Spot" that vanished by the time the Hubble Space Telescope imaged Neptune five
years later.
Neptune Orbiter was a proposed NASA unmanned planetary spacecraft to explore the planet Neptune. It
was envisioned that it would be launched sometime around 2016 and take 8 to 12 years to reach the planet;
however, NASA's website no longer lists any possible launch date as the NASA program is no longer being
funded by the United State Government. The Neptune Orbiter was designed to answer many questions that
still surround the planet. Its main mission was to study Neptune's atmosphere and weather, its ring system,
and its moons, particularly Triton.
Inner Planets Overview
•
Also known as Terrestrial Planets (meaning Earth-like)
•
Made up of rock and metal
•
Warmer than Outer Planets
•
Much smaller than Outer Planets
•
Have relatively
–
High density
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Slow rotation
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Solid surfaces
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No rings
–
Few satellites
Outer Planets Overview
•
Also known as Jovian Planets (meaning Jupiter-like)
•
Made up of Hydrogen, Helium, and ices
•
Colder than Inner Planets
•
Much larger than Inner Planets, that’s why they are called “Giants”
•
Have relatively
–
Low density
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Rapid rotation
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Deep atmospheres
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Have rings
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Many satellites