1. Our Solar System

2. BIG Idea:
Using the laws of motion and gravitation, astronomers can understand the orbits and the properties of the planets and other objects in the solar system.

3. I. Models of the Solar System
A. Geocentric: the Sun, stars, and planets revolved around the Earth.
Aristotle promoted
this Earth-centered model

4. B. Heliocentric – the sun is the center of the universe
- Copernicus proposed this model

5. Kepler’s Laws
Explained planetary motion mathematically

6. Law of Ellipses: explains a planet’s path around the Sun
Ellipse: an oval whose shape is determined by two points (foci)
The Sun is at one focus of the orbit of a planet

7. Because the planets’ orbits are elliptical, they are not always the same distances from the sun…
Do you remember the word to describe the point in our orbit when we are closest to the Sun?
Farthest away?

10. There are TWO types of planets in our solar system…
How were you taught to remember them?

11. Planet Acronyms My Very Excellent Mother Just Served Us Nachos
My Very Excellent Mother Just Served Us Noodles
My Very Educated Mother Just Served Us Nachos

12. II. The Inner Planets (4 planets closest to the Sun)
Terrestrial Planets: Earth-like (rocky)

13. A. Mercury Closest to the Sun Shortest orbit of 88 days
Heavily cratered
Huge temperature range 427ºC in day, -173ºC at night
Mariner 10 – visited the planet in 1974 and 1979

14. B. Venus Earth’s twin (size, mass, density)
Rotation direction is opposite that of other planets
Pressure is 90x Earth’s
Hot surface
(464ºC)
Dense atmosphere (mostly CO2)
Magellan Probe

15. C. Earth Third planet from Sun Orbital period of 365.24 days
Completes one full rotation in 23 hours 56 minutes
Fifth largest planet
Located between the Sun
and the asteroid belt
One natural satellite, the
moon

16. Life on Earth is possible because…
…of the Earth’s distance from the Sun
Temperature is warm enough for water to exist as a liquid
Water occurs on Earth as a solid (ice), a liquid, or a gas (water vapor)
The only known planet with the proper combination of water, temperature, and oxygen to support plant and animal life

18. Earth’s Atmosphere

19. What causes the seasons on Earth?
Earth’s revolution around the Sun, TILTED ON ITS AXIS !

21. D. Mars Axis is tilted like Earth’s Very thin atmosphere (mostly CO2)
Olympus Mons – shield volcano
Largest known volcano in
our solar system
3X higher than Mt. Everest
Viking 1 – found evidence of water erosion

22. III. The Outer Planets
Jovian Planets: Jupiter-like gas giants

23. A. Jupiter Largest planet Fastest rotation - every 10 hours
Orbital period is 12 years
More than 60 moons
Mostly hydrogen and helium
Great Red Spot – giant rotating storm (over 300 years long)
Galileo

24. B. Saturn Average temp: -176ºC Least dense planet
Orbital period is 29.5 years
Complex system of rings
Cassini Spacecraft

25. C. Uranus Rotates horizontally The ‘tipped’ planet
Orbital period is 84 years
Greenish color
Methane atmosphere
Voyager 2

26. D. Neptune Orbital period is 164 years 8 moons and possibly 4 rings
Upper atmosphere composed of white clouds of frozen methane (appear as bands moving between equator and poles)
Great Dark Spot – huge storm
Solar system’s strongest winds – exceeding 1,000 km/hr

27. IV. Other Solar System Objects

28. A. Dwarf Planets
An object that, due to its own gravity, is spherical in shape, orbits the Sun, is not a satellite, and has not cleared the area of its orbit of smaller debris.

29. 1. Pluto (now ‘asteroid #134340’)
Late to be discovered (1930)
Mostly frozen methane, rock, and ice
Demoted from planet
status to “dwarf planet” in August 2006
Not always the furthest planet from the sun

30. Ceres: largest body in the Asteroid Belt
Eris:
largest known dwarf planet
27% more massive than Pluto

32. B. Small Solar System Bodies

33. 1. Asteroids thousands orbiting the Sun between Mars and Jupiter
rocky bodies
vary in diameter
pitted, irregular surfaces

34. Asteroid Belt between Mars and Jupiter
remains of unformed planets (planetesimals)

35. meteoroid: small bits of rocks and metal left by a comet or asteroid collision
meteor: bright streak of light produced by meteoroids burning up as they enter our atmosphere
meteorite: meteoroid (or part of one) that is left after it hits the Earth

36. Meteorite: meteoroid that makes it to Earth
Meteor Shower
Meteorite: meteoroid that makes it to Earth
“shooting stars”

38. When large meteorites strike Earth, they produce impact craters:

40. 2. Comets small, icy bodies of rock, dust, methane and ammonia
orbit the Sun in long ellipses

41. Nucleus: small solid core, which is made up of rocks, metals, and ice
Tail: gas and dust

42. In relation to the Sun, what do you notice about the tails of the comets?

43. The tails always point AWAY from the Sun!
Their tails of gas and dust are pushed away by radiation from the Sun.