1. Intro to Space:
Our Solar System

2. The Basic Concepts Our solar system consists of 4 basic parts. The Sun
Tiny interior rocky planets
Larger exterior gas planets and their icy moons
Oort Cloud of “ice balls”

3. Mass of the Solar System
The Sun is virtually all all of the mass.
The rest is about equal parts Jupiter, the other planets, and the Oort cloud

4. The Sun
solar flare
The Sun contains percent of all matter in the solar system. The Sun is a star and it is composed of hydrogen and helium.
Period of Rotation: 25.4 days at equator, up to 30 days at poles. Mass: 333,000 x that of Earth. Diameter: 870,000 miles (1.4 million kilometers). Temperature: 27 million °F (15 million °C) in core; 11,000°F (6,100°C) at surface.
The Sun is only an average size, an average temperature. Looking at the galaxy that contains it and more than one hundred billion other stars, you’d never take notice of our sun, revolving around the center of the Milky Way, about halfway out on the inside edge of one of the galaxy’s spiral arms.
sun spots
solar wind

5. MERCURY Average distance from Sun 0.387 AU (57,909,175 km)
Mercury, the planet nearest the Sun, is the smallest planet in our solar system.
It is only slightly larger than the Earth's moon. The surface is covered with craters.
This tiny planet does not have any rings or moons.
Average distance from Sun AU (57,909,175 km)
Rotation period (length of day in Earth days) Revolution period (length of year in Earth days) 87.97
Mercury's orbit is so close to the Sun that it is difficult to see. This explains why some early astronomers didn’t see it. Viewed from Earth, Mercury is never far from the Sun in the sky. Because the Sun is so bright, Mercury can only be seen in twilight.
Timocharis made the first recorded observation of Mercury in 265 BC
Atmospheric components trace amounts of hydrogen and helium
Surface materials are basaltic and anorthositic rocks and regolith
evidence of
craters

6. VENUS Average distance from Sun 0.723 AU (108,208,930 km)
impact craters
lava flows
Venus is one of the brightest objects in our sky,
so it is clearly visible to the naked eye.
It can be tricky to spot because it is always
near the Sun.
It rises and sets with the Sun each day.
Ancient civilizations believed Venus was
actually two different objects,
so they called the one that rose the
Morning Star, and the one that set
the Evening Star.
Average distance from Sun AU (108,208,930 km)
Rotation period (length of day in Earth days) (retrograde)
Revolution period (length of year in Earth days)
Atmospheric components 96% carbon dioxide, 3% nitrogen, 0.1% water vapor
Surface materials- basaltic rock and altered materials
Since Venus can be seen with the naked eye, no one really knows who discovered Venus. Venus’ beautiful color made it easy for ancient astronomers to find it in the night sky long before the invention of the telescope.
Interesting Facts About Venus
In the 1950's astronomers noticed that Venus rotates in the opposite direction of Earth. On Venus, the Sun rises in the west and sets in the east. Hottest planet in our solar system.
A canyon on Venus is four times as big and twice as deep as the Grand Canyon.
Venus probably once had oceans, but they all boiled away into the atmosphere.

7. EARTH and MOON
What similarities and
differences do you notice
between the Earth and the
Moon?
Why do they have such
different surface features?
Average distance from Sun 1 AU (149,597,890 km) Rotation period (length of day in Earth days) 1 (23.93 hours) Revolution period (length of year in Earth days)
Atmospheric components 78% nitrogen, 21% oxygen, 1% argon Surface materials basaltic and granitic rock and altered materials

8. MARS Average distance from Sun 1.524 AU (227,936,640 km)
Mars is very bright, which makes it easy to spot in the night sky. It was named after
the Roman god of war because its reddish color reminded the people of blood.
Olympus Mons is the largest volcano in our solar system!
Although people have
never landed on Mars,
we have sent robotic
explorers there.
Average distance from Sun AU (227,936,640 km)
Rotation period (length of day in Earth days)
Revolution period (length of year in Earth days)
Atmospheric components 95% carbon dioxide, 3% nitrogen, 1.6% argon
Surface materials- basaltic rock and altered materials
Discovery
Since Mars is so bright and easy to see with the naked eye, we don't know who exactly discovered Mars. Ancient astronomers could see it long before the invention of telescopes.
Missions to Mars
Mariner 4, 6, 7, & 9 Viking I & II Mars Observer Mars Pathfinder Mars Global Surveyor Mars Polar Lander
Interesting Facts About Mars
Mars has the tallest mountain (Olympus Mons) in the solar system, three times the size of Mt. Everest. Mars’s moons, which are shaped like potatoes, probably used to be asteroids.
Martian crater

9. ASTEROID BELT
Most asteroids can be found in the Asteroid Belt, which is located between
Mars and Jupiter. Asteroids are rocky and metallic objects that orbit the Sun,
but are too small to be considered planets. They are known as minor planets.
Asteroids range in size from Ceres, which has a diameter of about 1000 km,
down to the size of pebbles.
Asteroids are sometimes called Minor planets. They are small rocky bodies.
They are made up of leftover material from our solar system.
Largest asteroid 1 Ceres Total discovered to date Over 250,000 designations have been assigned by the Minor Planet Center; over 100,000 have been observed more than once. Total numbered asteroids to date.Over 30,000. Near-Earth asteroids Around 1.0 AU from earth, with perihelia less than or equal to 1.3 AU.

10. JUPITER
Jupiter, the fifth planet from the Sun, is the largest planet in our solar system.
Jupiter is so big that over 1,000 planets the size of Earth could fit into it.
It has over 60 moons and 2 rings.  Can life exist on Jupiter's moon, Europa?
The “Great Red Spot”
Is actually a huge
Storm system!
average distance from Sun AU (778,412,020 km)
Rotation period (length of day in Earth days) 0.41 (9.8 Earth hours)
Revolution period (length of year in Earth years) 11.86
Discovery
Jupiter is the largest planet in our solar system, and it is one of the brighter objects in the night sky. No one knows for sure who discovered Jupiter, but we know the ancient Greeks named it after the god, Zeus.
Missions to Jupiter
Pioneer 11 (USA) April 6, 1973
Pictures of Jupiter and its Great Red Spot
Voyager 1 (USA) September 5, 1977
Photographs and information on Jupiter's many moons.
Voyager 2 (USA) August 20, 1977
Found that Jupiter's Great Red Spot is really a complex storm.
Found that Io, one of Jupiter's moons, has active volcanoes.
Galileo (USA and Europe) October 18, 1989
Entered Jupiter's atmosphere.
Interesting Facts About Jupiter
Largest planet in our solar system
Has the largest moon in our solar system
Shortest day
Largest storm (Great Red Spot) three times the size of Earth
Pressure on Jupiter is so great it would crush a spaceship
Here are a few of Jupiter’s moons

11. SATURN
Saturn, the sixth planet from the Sun, is the second largest planet in our solar system.
It is often called the ringed planet because many rings of dust and rocks surround it.
Saturn also has over 31 moons.
Saturn with some of
its moons
Some of Saturn’s rings
Average distance from Sun AU (1,426,725,400 km)
Rotation period (length of day in Earth days) 0.44 (10.2 Earth hours)
Revolution period (length of year in Earth years) 29.46
Discovery Saturn is clearly visible in the night sky. The ancient Greeks named the planet after the god of agriculture and time. It wasn't until 1655, however, that we knew Saturn had rings. Galileo saw them, but he didn't know what they were. Another astronomer, Christian Huygens, later discovered they were rings.
Missions to Saturn:
Pioneer 11 (USA) April 6, 1973
Took pictures of Saturn. Discovered new rings and moons.
Voyager 1 (USA) September 5, 1977
Took pictures of Saturn's moons. Discovered how complex Saturn’s rings were.
Voyager 2 (USA) August 20, 1977
Took pictures of Saturn's moons.
Cassini (USA, European Space Agency, Italy) October 13, 1997
Experiments will help scientists understand Saturn's moons, rings, and atmosphere. Will send a probe into Titan's atmosphere.
Interesting Facts About Saturn
Has the most moons Has thousands of rings made of ice, dust, and rocks The farthest planet you can see without a telescope The planet would float if you put it in water
Atmospheric components 97% hydrogen, 3% helium, .05% methane Rings Rings are 270,000 km in diameter, but only a few hundred meters thick. Particles are centimeters to decameters in size and are ice (some may be covered with ice); there are traces of silicate and carbon minerals. There are four main ring groups and three more faint, narrow ring groups separated by gaps called divisions.
Titan is a moon of Saturn that may have some
Conditions necessary for life! The picture on
the right shows an artist’s drawing of how Titan
might have looked when the Cassini-Huygen’s
probe dropped into its atmosphere in Dec., 2004.

12. URANUS
Uranus is a very unusual planet because it sits on its side with north and south
poles sticking out the sides. It rotates around this axis, making it look like a ball
rolling around in a circle around the Sun.
Average distance from Sun AU (2,870,972,200 km)
Rotation period (length of day in Earth days) 0.72 (17.9 Earth hours)(retrograde)
Revolution period (length of year in Earth days) 30,685 (84 Earth years)
Atmospheric components 83% hydrogen, 15% helium, 2% methane (at depth)
Rings Uranus has a system of narrow, faint rings. Ring particles are dark, and could consist of rocky or carbonaceous material.
Discovery
Astronomer William Herschel discovered Uranus in Using a telescope, he spotted a dim object. He watched it for years and decided it had to be a planet given its orbit.
Herschel also discovered two of Uranus’ moons in Voyager II spotted many of its other moons in 1986.
In 1977, scientists saw Uranus blink several times. They later discovered that rings surrounding the planet caused the blinking. These rings are very dark and narrow, unlike Saturn's, which are bright and colorful. Voyager II sent back many pictures that clearly show these rings.
Missions to Uranus
Voyager 2 (USA) August 20, 1977
Took thousands of pictures of Uranus, its rings, and its moons.
Interesting Facts About Uranus
Herschel argued with other astronomers over the new planet's name. He wanted to name it after King George III of Great Britain. Other astronomers wanted him to name it after himself. Uranus was named after Ouranos, one of the first gods in Greek mythology. Uranus’ moons have names from Shakespearean plays. Since Uranus lies nearly on its side, its North Pole gets 42 years of daylight while the South Pole gets 42 years of darkness. Uranus’ rings might have formed from broken moons.
some of Uranus’s moons
Black rings

13. NEPTUNE
Neptune, usually the eighth planet from the Sun, is a very cold place.
Occasionally, Pluto crosses Neptune’s orbit and becomes the eight planet.
Its bluish color comes from its atmosphere of methane gas.
average distance from Sun AU (4,498,252,900 km)
Rotation period (length of day in Earth days) 0.67 (19.1 hours)
Revolution period (length of year in Earth days) 60,190 (164.8 Earth years)
Atmospheric components 74% hydrogen, 25% helium, 1% methane (at depth)
Rings are narrow, and contain concentrations of particles called ring arcs.
Discovery
Neptune wasn't discovered the way all the other planets in our solar system were found. Astronomers didn't scan the sky with their powerful telescopes to find Neptune. They used math instead!
After the discovery of Uranus, astronomers were having trouble figuring out Uranus’ orbit. They realized that there must be another planet farther out than Uranus because this unknown planet’s gravitational pull slightly changes Uranus' orbit. They were right! French astronomer Leverrier and English astronomer John Couch Adams made the mathematical calculations of where Neptune should be in 1843, and German astronomer Johann Galle found it in 1846.
Missions to Neptune
Voyager 2 (USA) August 20, 1977
Took thousands of pictures of Neptune, its rings, and its moons.
Interesting Facts About Neptune
Neptune was actually the farthest planet from the Sun from February 7, 1979 until February 11, 1999 (the order was Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Pluto, and Neptune). Neptune will be the 8th farthest planet from the Sun until the 23rd century. Neptune’s Great Dark Spot is a huge storm the size of Earth.
Tiny Dark Moon

14. PLUTO Pluto, demoted from being the ninth planet from the Sun.
Some scientists believe that Pluto once was one of Neptune’s moons, and that it
pulled out away from Neptune and made its own orbit.
Average distance from Sun AU (5,906,376,200 km)
Rotation period (length of day in Earth days) 6.39 (retrograde)
Revolution period (length of year in Earth years)  247.92
Atmospheric components perhaps methane and nitrogen
Surface materials perhaps methane ice
Discovery: After the discovery of Neptune in 1846, scientists believed that there still might be a ninth planet, and they set out to find it. Finding Pluto was difficult. Pluto is very small, it is a long way from the Sun, and it is very dim in the sky. The planet moves very slowly, taking 248 years to complete its orbit around the Sun, so it took many years before Pluto’s motion could help identify it. An amateur American astronomer, Clyde Tombaugh, finally found Pluto in 1930.
Missions to Pluto
Pluto is the only planet that has not been visited by a spacecraft from Earth. The Pluto Express probe has been delayed.
Interesting Facts About Pluto
Pluto was not the farthest planet from the Sun from February 7, 1979 until February 11, (the order was Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Pluto, and Neptune). Pluto will be the farthest planet from the Sun until the 23rd century. Pluto’s moon, Charon, is very close to Pluto and about the same size.
Clearest view to date
Of Pluto and Charon

15. COMETS Comets are icy planetesimals formed in the outer solar system.
Comets are sometimes called dirty snowballs or "icy mudballs".
They are a mixture of ices (both water and frozen gases) and dust that for
some reason didn't get incorporated into planets when the solar system was formed.
This makes them very interesting as samples of the early history of the solar system.
Comets have
elliptical orbits.
Comets are icy planetesimals formed in the outer solar system.
They are composed mainly ice and dust
They have highly elliptical orbits which take them very close to the Sun and back out into deep space, often far beyond the orbit of Pluto. Their orbit duration can be from less than 200 years to more than several millions of years.
Composition of comets:
Nucleus- Main body of the comet: composed of dust particles trapped in a mixture of ices of water, carbon monoxide, carbon dioxide, methane, and ammonia. Typically only a few kilometers in diameter
Coma- A halo of evaporated gas and dust which forms when the comet approaches the inner solar system. The coma grows larger as the comet gets closer to the sun.
When we see a comet, we
are seeing the tail of the comet
as comes close to the Sun.
Comet Halley in 1910

16. Homework
Read 8.1
Pg 308 #2, 5, 8, 9
Pg 317 #5, 9