Guided Notes on Our Guided Notes on Our Solar SystemSolar System

Chapter 29, Section 1 and Chapter 29, Section 1 and

Chapter 29, Section 4Chapter 29, Section 4

1.1. In 1543, Copernicus In 1543, Copernicus suggested that the suggested that the Sun was Sun was the center of the Solar the center of the Solar SystemSystem. This is known as the . This is known as the heliocentricheliocentric model of the model of the solar system.solar system.

2. 2. In a heliocentric model, the In a heliocentric model, the inner planets move faster in inner planets move faster in their orbits than the outer their orbits than the outer planets do.planets do.

3. 3. Kepler’s first law states that Kepler’s first law states that each planet orbits the Sun in an each planet orbits the Sun in an ellipse, rather than a circleellipse, rather than a circle. An . An ellipse is an ellipse is an oval shape that is oval shape that is centered on 2 pointscentered on 2 points, instead of , instead of a single point, as in a circle.a single point, as in a circle.

4. 4. Each planet’s elliptical orbit Each planet’s elliptical orbit is a is a different size and shapedifferent size and shape, , and the and the SunSun is always at one is always at one focusfocus..

5. 5. The length of time it takes The length of time it takes for a planet to travel a for a planet to travel a complete elliptical orbit complete elliptical orbit around the Sun is around the Sun is called the called the orbital periodorbital period..

6. 6. Kepler’s second law found that Kepler’s second law found that an imaginary line between the an imaginary line between the Sun and a planet sweeps out Sun and a planet sweeps out equal amounts of area in equal equal amounts of area in equal amounts of time.amounts of time.

77. Issac Newton’s law of universal . Issac Newton’s law of universal gravitation states that gravitation states that every every pair of bodies in the universe pair of bodies in the universe attract each other with a force attract each other with a force that is proportional to the that is proportional to the product of their masses and product of their masses and inversely proportional to the inversely proportional to the distance between them.distance between them.

8. 8. Stars and planets form from Stars and planets form from clouds of gas and dustclouds of gas and dust, , called interstellar clouds, called interstellar clouds, which exist in space which exist in space between the stars.between the stars.

9. 9. HydrogenHydrogen and and HeliumHelium make make up most of the interstellar up most of the interstellar cloud.cloud.

10. 10. An interstellar cloud can start An interstellar cloud can start to condense as a result of to condense as a result of gravitygravity and and become become concentrated enough to form a concentrated enough to form a star and planetsstar and planets. Astronomers . Astronomers believe our solar system formed believe our solar system formed this way.this way.

11. 11. A solar nebula is A solar nebula is the disk of the disk of dust and gas that formed dust and gas that formed the Sun and planets.the Sun and planets.

12. 12. The growth of planets The growth of planets occurs because of continued occurs because of continued collisions and mergers of collisions and mergers of planetesimals.planetesimals.

13. 13. The inner planets are rocky The inner planets are rocky and dense because the Sun’s and dense because the Sun’s gravitational force gravitational force swept up swept up much of the gas in the area of much of the gas in the area of the inner planets.the inner planets.

14. 14. Jupiter’s gravitational force Jupiter’s gravitational force prevented the planetesimals prevented the planetesimals in the in the asteroid belt asteroid belt from from merging to form a planet.merging to form a planet.

15. 15. Asteroids range in size Asteroids range in size from from a few kilometers to a few kilometers to about 1000 km in diameterabout 1000 km in diameter and have and have pitted, irregular pitted, irregular surfaces.surfaces.

16. When interplanetary material 16. When interplanetary material enters Earth’s atmosphere, it is enters Earth’s atmosphere, it is called a called a meteoroidmeteoroid. If it burns up in . If it burns up in Earth’s atmosphere, it will produce Earth’s atmosphere, it will produce a streak of light called a a streak of light called a meteormeteor. . Pieces that do not completely burn Pieces that do not completely burn up and collide with the ground are up and collide with the ground are called called meteoritesmeteorites..

17. 17. Comets are Comets are small, icy small, icy bodies that have highly bodies that have highly eccentric orbits around the eccentric orbits around the Sun. Sun. They are made of They are made of iceice and and rockrock..