1. Chapter 29 – Our Solar System
"The earth is the cradle of humankind, but one cannot live in the cradle forever."
-- Konstantin Tsiolkovsky, 1895

2. 29.1 Overview of our solar system
OBJECTIVES
Describe early models of our solar system.
Examine the modern heliocentric model of our solar system.
Relate gravity to the motions of celestial bodies.

3. Geocentric ,meaning “Earth Centered”
Early Ideas
Geocentric ,meaning “Earth Centered”
In the early 1500s, Nicholas Copernicus formulated the heliocentric model of the solar system.

4. Copernicus
Nicolaus Copernicus found that in a heliocentric model of the solar system,
the inner planets move faster in their orbits than the outer planets,
giving the appearance from Earth that some planets move in a retrograde motion.
( )

5. Retrograde Motion
Retrograde motion is the movement of a planet in an opposing direction across the sky.

6. Galileo
Galileo’s discovery of Jupiter’s moons proved that not all celestial bodies orbit Earth; therefore, Earth is not necessarily the center of the solar system.

7. Kepler’s First Law
Kepler’s first law demonstrates that each planet has an elliptical orbit of unique size and shape with the Sun at one focus.

8. Earth’s average distance from the Sun: 1.496 x 108 km AU
Earth’s average distance from the Sun: x 108 km
or 1 astronomical unit.

9. Planets’ Orbits
All of the planets (& former planets) and their satellites orbit the Sun in the same direction, and all their orbits, except Pluto's lie near the same plane.

10. Eccentricity
When a planet is closest to the sun in its orbit, it is at ____________ and when it is farthest from the sun, it is at _________.
perihelion
aphelion

11. Ellipses Terms to be familiar with. Major axis Foci Semi-major axis
Perihelion
Sun
Aphelion

12. Eccentricity
e =
Distance between foci
Major axis length

13. Kepler’s Second Law
Closer  Faster
Farther  slower
Kepler’s second law is an imaginary line between the Sun and a planet that sweeps out equal amounts of area in equal amounts of time.

14. Center of Mass
Isaac Newton determined that each planet does not orbit the Sun but instead orbits a center of mass between it and the Sun.

15. 29.1 Overview of our Solar System Quiz

16. 29.2 The Terrestrial Planets
OBJECTIVES
Describe the properties of the terrestrial planets.
Compare Earth with the other terrestrial planets.

17. Precession
The wobble of the Earth’s rotational axis is called precession.
The Moon’s gravitational force on Earth causes the sideways push that is responsible for precession.

18. Mariner 10 image of Mercury
has the largest day-night temperature difference of all the planets in the solar system.
Mariner 10 image of Mercury

19. Venus
Venus - Computer Simulated Global View Centered at 180 Degrees East Longitude
is the planet most similar to Earth in physical properties, such as diameter, mass, and density.

20. Venus (more)
The high concentration of carbon dioxide (CO2) in the atmosphere of Venus inhibits infrared radiation from escaping and keeps the surface extremely hot.

21. Image by Reto Stöckli (land surface, shallow water, clouds).
Earth
Image by Reto Stöckli (land surface, shallow water, clouds).
is the only known planet in our solar system where H2O is present in three states, solid, liquid & gas.

22. Terrestrial
planets are close to the size of Earth and have solid and rocky surfaces, while the gas giant planets are larger, more gaseous, and lack solid surface.

23. 29.2 The Terrestrial Planets23

24. Atmospheric conditions of the four terrestrial planets
Mercury
Venus
Earth
Mars
thick clouds
primarily of carbon dioxide and nitrogen
Include sulfuric acid
almost non-existent
mostly oxygen and sodium
thin and there is consistent wind.
composition is similar to Venus’s
moderately dense
composed of 78% nitrogen and 21% oxygen
Earth
Mercury
Venus
Mars

25. 29.3 The Gas Giant Planets OBJECTIVES
Describe the properties of the gas giant planet.
Identify the unique nature of the object “formerly-known-as-the-Planet-Pluto”.

26. 29.3 The Gas Giant Planets 26

27. 29.3 the object “formerly-known-as-the-Planet-Pluto”.27

28. Composition
The gas giants are composed primarily of lightweight elements, such as hydrogen, helium & methane.
Saturn
Uranus
Jupiter
Neptune

29. Rapid Rotation
The rapid rotation of the largest gas giant Jupiter, causes its clouds to flow in alternating cloud types called belts and zones.
Jupiter
Belts are low, warm, dark-colored clouds that sink. Zones are high, cool , light-colored clouds that rise.

30. Blue Color
Neptune and Uranus , the two gas giants appear blue because of the methane in their atmosphere.
Uranus
Neptune

31. Neptune
Neptune has clouds and atmospheric belts and zones similar to those of Saturn and Jupiter.
Neptune

32. Pluto’s Eccentricity
Pluto’s orbit is so eccentric that while at perihelion, Pluto is closer to the Sun than Neptune is.
Pluto's orbit seen from the plane of the ecliptic, showing its high inclination compared to the other planets
The eccentric orbit of Pluto is 50 AU from the Sun at aphelion and almost 30 AU from the Sun at perihelion.

33. Terrestrial and the Gas giant planets
Both are categories of the planets of our solar system
Gas giant planets
Terrestrial planets
four planets close to the Sun
Mercury, Venus, Earth, and Mars
solid, rocky surfaces
smaller
farther from the Sun
Jupiter, Saturn, Uranus, and Neptune
more gaseous
lack a solid surface
larger

34. 29.2 & 29.3 Quiz (8pts) Riddle me this .

35. 29.4 Formation of Our Solar System
OBJECTIVES
Describe how the planets formed from a disk surrounding the young sun.
Explore remnants of solar system formation.

36. Interstellar Cloud
Interstellar cloud, a cloud of gas and dust from which stars and planets are formed.

37. Solar Nebula Theory
Interstellar cloud can condense and become concentrated enough to form a star and possibly planets.
The dense concentration of gas at the center of the solar nebula eventually became the Sun.

38. Planetismals
Planetismals are tiny grains of condensed material that accumulate and merge together to form these large bodies possibly growing until they reach hundreds of kilometers in diameter.

39. Asteroids
Bodies of interplanetary debris that orbit the Sun with most in the area between Mars and Jupiter are called asteroids.

40. Comets
Comets are small, icy body made of ice and rock that has a highly eccentric orbit around the Sun.
The Oort cloud and the Kuiper belt are two cluster of comets.
Haley 's comet seen here in It will appear again in 2062.

41. Meteor
The result when Earth intersects a cometary orbit is a meteor shower.

42. Meteor
Meteor is interplanetary material that burns up and becomes a bright, glowing streak of light in Earth’s atmosphere.
Two examples are the Perseids (August) & Leonid (November).

43. Meteorite
Is interplanetary material that enter’s Earth’s atmosphere and collides with the ground rather than burning up. 43

44. 29.4 Quiz