1. The Solar System Target 7: I can explain the theory of the formation of the solar system

2. Early Belief about the Universe  Astronomers believed that the sun and planets revolved around the Earth  a geocentric universe  Geocentric = Earth centered  Astronomers believed that the sun and planets revolved around the Earth  a geocentric universe  Geocentric = Earth centered

3. However…  If the planets move around the Earth, why did some of them seem to sometimes go in reverse?  Mars exhibits retrograde motion, moving in the opposite direction in the sky  If the planets move around the Earth, why did some of them seem to sometimes go in reverse?  Mars exhibits retrograde motion, moving in the opposite direction in the sky

5. What would retrograde motion look like for each type of system? Left: HeliocentricRight: Geocentric

6. Out with the old in with the new!  In 1563 Nicolaus Copernicus proposed that the Sun was the center of the solar system!  Heliocentric model = Sun centered  In 1563 Nicolaus Copernicus proposed that the Sun was the center of the solar system!  Heliocentric model = Sun centered

9. Astronomers’ contributions  Copernicus—heliocentric solar system  Kepler—planets have Elliptical orbits with Sun at one focus (Kepler’s 1 st Law)  Copernicus—heliocentric solar system  Kepler—planets have Elliptical orbits with Sun at one focus (Kepler’s 1 st Law)

11. Galileo —discovery of Jupiter’s moons proves that not all celestial bodies orbit Earth Newton—developed laws of gravity to explain planets orbits in 1665 Galileo —discovery of Jupiter’s moons proves that not all celestial bodies orbit Earth Newton—developed laws of gravity to explain planets orbits in 1665

12. Formation of the Solar System! Solar Nebula Theory: Began with a cloud of interstellar gas and dust, which began to: collapse heat up spin (rotate) and flatten (which is why the planets are in the same plane as the Sun!) https://www.youtube.com/watch?v=PL3YNQK960Y Solar Nebula Theory: Began with a cloud of interstellar gas and dust, which began to: collapse heat up spin (rotate) and flatten (which is why the planets are in the same plane as the Sun!) https://www.youtube.com/watch?v=PL3YNQK960Y

13. Collapse

14. Heat Up

15. Spinning

16. Flatten out

17. Final Form

20. Differences between the planets  In the center of the disk the Sun formed, with the planets forming around it according to temperature differences!  Gas Planets - formed farther away from the Sun where it was cool enough for the gases and ices to collect.  Terrestrial Planets - formed closer where it was hotter and is why they are made up of rock and metal).  In the center of the disk the Sun formed, with the planets forming around it according to temperature differences!  Gas Planets - formed farther away from the Sun where it was cool enough for the gases and ices to collect.  Terrestrial Planets - formed closer where it was hotter and is why they are made up of rock and metal).