1. Bell Ringer
_______ tides occur during New Moon and Full Moon. _______ tides occur during First Quarter and Third Quarter.
YOU HAVE A VOCAB QUIZ MONDAY – UNIT TEST ON WEDNESDAY
Spring
Neap

2. The SOLAR SYSTEM

3. Solar Nebula Hypothesis
Solar System – the collection of planets, their moons, and smaller bodies that orbit the Sun due to the Sun’s gravity

4. Solar Nebula Hypothesis
Interstellar clouds – clouds of gases (like hydrogen and helium) and dust that lead to the formation of stars and planets
Solar nebula – name of the interstellar cloud that formed OUR solar system

5. Solar Nebula Hypothesis
Solar Nebula Hypothesis – hypothesis that the Sun, planets, and the rest of the solar system formed from an interstellar cloud (nebula)

6. Solar Nebula Hypothesis
A strong force like the explosion of a nearby star made gases gather together and form into the solar nebula
1. Solar Nebula

7. Solar Nebula Hypothesis
2. The gases gathered closer together because of gravity, and the nebula began to spin
1. Solar Nebula
2. Gases gather

8. Solar Nebula Hypothesis
The center of the cloud grew hotter and denser, eventually forming the Sun
The rest of the cloud became thinner (like a disk)
1. Solar Nebula
2. Gases gather

9. Solar Nebula Hypothesis
3. Particles in the thin part of the cloud began to clump together, forming planetesimals
The planetesimals eventually grew into ______
planets
1. Solar Nebula
3. Planetesimals form
2. Gases gather

10. Solar Nebula Hypothesis
4. The particles continued to form planets, while most of the remaining gases were blown away by the Sun’s solar winds
1. Solar Nebula
3. Planetesimals form
4. Solar System
2. Gases gather

11. Models of the Solar System
Geocentric Model (Earth-centered) – early belief that everything orbited around the Earth, while the Earth remained stationary
Why would the geocentric model seem to make sense to observers on Earth?

12. Early Ideas about the Solar System
Problem with Geocentric Model:
While the stars all moved across the sky at the same speed and same direction, the planets sometimes moved in the opposite direction
Retrograde motion – a planet’s backward motion across the sky
Tracking Mars across the night sky in 2005

13. Early Ideas about the Solar System
Heliocentric Model (Sun-centered) – belief that the Earth and other planets orbit around a stationary Sun (correct model)
Provided a simple explanation for retrograde motion, because all of the planets are moving in relation to the Sun, not the Earth

14. Early Ideas about the Solar System
Galileo’s discovery of four of Jupiter’s moons helped the scientific community adopt the heliocentric model (if Jupiter had things orbiting it, then not all things orbited Earth)
Jupiter and 4 of its moons, as seen from a telescope on Earth

15. Early Ideas about the Solar System
Geocentric model stated that the _______ was the center of the solar system.
Heliocentric model stated that the _____ was the center of the solar system.
Our current model of the solar system is the ____________ model.
Earth
Sun
Heliocentric

16. Kepler’s and Newton’s Laws
Kepler’s First Law – each planet follows an elliptical (oval-shaped) orbit around the Sun

17. Kepler’s and Newton’s Laws
A planet in an elliptical orbit is not a constant distance from the Sun
Perihelion – part of an orbit closest to the Sun
Aphelion –part of an orbit farthest from the Sun

18. Kepler’s and Newton’s Laws
Eccentricity – a number (0-1) that describes the shape of an orbit
0 = a perfect circle orbit
1 = a very elongated oval orbit
Earth’s current eccentricity =

19. Kepler’s and Newton’s Laws
Kepler’s Second Law – a planet covers equal area on its orbit in equal amounts of time

20. Kepler’s and Newton’s Laws
Kepler’s Third Law – the farther away a planet is from the Sun, the longer it takes to complete its orbit
Example: If Earth is 1 AU from the Sun and Saturn is 10 AU away, which one takes longer to orbit the Sun?
Saturn

21. Kepler’s and Newton’s Laws
Newton’s Law of Universal Gravitation – the force of gravity between two objects increases with the size of the objects and how close they are to each other
Example: Which two bodies would attract more gravity? OR
Two small bodies far away from each other?
Two large bodies close together?

22. Kepler’s and Newton’s Laws
Which two bodies would experience the MOST gravity?
Question 1: Question 2:
You and a classmate An ant and the Earth
You and the Earth An elephant and the Earth
You and Pluto A skyscraper and the Earth

23. Kepler’s and Newton’s Laws
Did you know that the Sun moves?
Barycenter – the center of mass between two large objects that the objects orbit around

24. Kepler’s and Newton’s Laws
The Sun is so much more massive than most planets, so the barycenter is within the Sun
However, Jupiter’s mass is big enough that the barycenter is slightly outside the Sun
The Sun and Jupiter orbit around that point

25. Kepler’s Laws Four-Square individual work!
Kepler’s First Law (label)
Definition
Picture (with perihelion and aphelion labels)
Kepler’s Second Law (label)
Definition
Picture
Kepler’s Third Law (label)
Definition
Picture
Universal Law of Gravitation
Definition
Picture (different than the one in notes)

27. Moon WS From yesterday’s notes (we ran out of time)
Work together in groups of 1-3 (1 sheet/group) and turn in.

28. Astronomy Review WS Covers 6.1-6.3 – working individually
Turn in when done.

29. Origins of the Solar System Video