1. You have a quiz next Wednesday/Thursday
You have a quiz next Wednesday/Thursday. It will cover mastery checks #7-#12

2. The solar system exhibits clear patterns of composition and motion.
These patterns are far more important and interesting than numbers, names, and other trivia.
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3. Sun Over 99.9% of solar system’s mass Made mostly of H/He gas (plasma)
Converts 4 million tons of mass into energy each second
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4. Mercury Made of metal and rock; large iron core
Desolate, cratered; long, tall, steep cliffs
• Very hot and very cold: 425°C (day), –170°C (night)
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5. Mercury
Mercury’s surface is scarred with countless impacts because it has no atmosphere to protect it from meteors and UV radiation from the sun.
Because of this reason, life would not be possible here.

6. • Even hotter than Mercury: 470°C, day and night
Venus
Nearly identical in size to Earth; surface hidden by clouds
Hellish conditions due to an extreme greenhouse effect
• Even hotter than Mercury: 470°C, day and night
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7. Venus may have been able to support life in the past...
But at some point in the past, it’s greenhouse effect went out of control so it kept heating up until now surface temperatures are almost 500 Celsius.
Because of this reason, life is not possible here.

8. Venus
We cannot see the surface because of the thick clouds made of sulfuric acid.
Russia landed a spacecraft on the surface but it only survived for a few minutes before the unhospitable conditions crippled it.

9. • A surprisingly large moon
Earth
Earth and Moon to scale
An oasis of life
The only surface liquid water in the solar system
• A surprisingly large moon
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10. The Moon
The moon can vary from -225 F in the shade to +70 F in the light? Why?
Because it has no atmosphere to stabilize the climate

11. Mars Looks almost Earth-like, but don’t go without a spacesuit!
Giant volcanoes, a huge canyon, polar caps, and more
Water flowed in the distant past and we have found proof that there is some liquid water still there.; could there have been life?
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12. Why can Mars no longer sustain life?
If you ask Mr. Jones, the single biggest reason is that Mars lost it’s magnetic field.
Every reason that Mars cannot sustain life can be traced back to Mars losing it’s magnetic field.

13. Magnetic Fields Explained

14. What Creates a Planet’s Magnetic Field?

15. The Molten Outer Core!

16. If both planets started out with a molten outer core at the same temperature, which would cool off faster and why?

17. Inside the frost line: Too hot for hydrogen compounds to form ices
Fig 9.5
Inside the frost line: Too hot for hydrogen compounds to form ices
Outside the frost line: Cold enough for ices to form
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18. Jupiter • Much farther from Sun than inner planets
Mostly H/He; no solid surface
300 times more massive than Earth
Many moons, rings • • •
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19. Io (shown here): Active volcanoes all over
Jupiter’s moons can be as interesting as planets themselves, especially Jupiter’s four Galilean moons
Io (shown here): Active volcanoes all over
Europa: Possible subsurface ocean
Ganymede: Largest moon in solar system
Callisto: A large, cratered “ice ball”
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20. Saturn • Giant and gaseous like Jupiter Spectacular rings
Many moons, including cloudy Titan
Cassini spacecraft currently studying it
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21. Rings are
NOT solid; they are made of countless small chunks of ice and rock, each orbiting like a tiny moon.
Artist’s conception
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22. Cassini probe arrived July 2004.
(Launched in 1997)
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23. Thursday, February 9, 12

24. Uranus • Smaller than Jupiter/Saturn; much larger than Earth
Made of H/He gas
and hydrogen compounds (H2O, NH3, CH4)
Extreme axis tilt Moons and rings • •
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25. Similar to Uranus (except for axis tilt)
Neptune •
Similar to Uranus (except for axis tilt) •
Many moons (including Triton)
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26. Pluto and Eris •
Much smaller than other planets Icy, comet-like composition
Pluto’s moon Charon is similar in size to Pluto
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27. Formation of Terrestrial Planets•
Small particles of rock and metal were present inside the frost line. •
Planetesimals of rock and metal built up as these particles collided. •
Gravity eventually assembled these planetesimals into terrestrial planets.
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28. Tiny solid particles stick to form planetesimals.
Summary of the Condensates in the Protoplanetary Disk
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29. Accretion of Planetesimals•
Many smaller objects collected into just a few large ones.
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30. Formation of Jovian Planets•
Ice could also form small particles outside the frost line. •
Larger planetesimals and planets were able to form. •
The gravity of these larger planets was able to draw in surrounding H and He gases.
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31. Where did asteroids and comets come from?
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32. Asteroids and Comets Leftovers from the accretion process
Rocky asteroids inside frost line
Icy comets outside frost line
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33. Heavy Bombardment •
Leftover planetesimals bombarded other objects in the late stages of solar system formation.
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