1. Earth Science Notes The Solar System

2. Models of the Solar System The Earth Centered Model Ptolemy was the early proponent Ptolemy was the early proponent Idea that the sun, moon, and stars were on fixed separate spheres that rotated around the earth. Idea that the sun, moon, and stars were on fixed separate spheres that rotated around the earth. AKA: geocentric model AKA: geocentric model

3. Models of the Solar System Ptolemy’s Earth-Centered Model

4. Models of the Solar System Sun-Centered model Nicholas Copernicus first to come up with the idea Nicholas Copernicus first to come up with the idea Idea that the moon revolved around the Earth and the Earth around the sun Idea that the moon revolved around the Earth and the Earth around the sun AKA: Heliocentric Model AKA: Heliocentric Model

5. Models of the Solar System Sun-Centered Model All orbits are circular All orbits are circular Sun is at the center Sun is at the center Stars do not move (with respect to each other) Stars do not move (with respect to each other)

6. Models of the Solar System Sun-Centered Model (cont.) Galileo was the first to prove this idea Galileo was the first to prove this idea –Showed with his telescope that Venus went through phases like our moon This must mean that Venus orbits the sun as well This must mean that Venus orbits the sun as well –Apparent changing of Venus’s diameter The Ptolemaic and Copernican models make very different predictions about the phases of Venus.

7. Models of the Solar System Modern Model of Solar System Made up of 8 planets (was 9) Made up of 8 planets (was 9) –Pluto is now reclassified as a dwarf-planet Planets have elliptical orbits Planets have elliptical orbits –Kelper’s first law of planetary motion Earth slows down Earth speeds up

8. Most of the mass of our solar system is the sun (99%) Relative sizes of planets to sun

9. Formation of the Solar System Ingredients: dust and debris Ingredients: dust and debris Large mass of dust and debris started to contract, forming discs with really dense centers. Large mass of dust and debris started to contract, forming discs with really dense centers.

10. Formation of the Solar System The centers of the disc became so dense and hot (10 million degrees C) that nuclear fusion began The centers of the disc became so dense and hot (10 million degrees C) that nuclear fusion began –This led to the formation of the sun

11. Formation of the Solar System Planets formed from the debris that did not get pulled into the center of the growing disc. Planets formed from the debris that did not get pulled into the center of the growing disc. Loose matter collided and stuck together; forming planets Loose matter collided and stuck together; forming planets The temperature close to the sun is high so it vaporized elements that had low boiling points The temperature close to the sun is high so it vaporized elements that had low boiling points –That is why the inner 4 planets are solid –The outer planets are made up of gases like helium, hydrogen, methane and ammonia.

12. Formation of the Solar System

13. Formation of the Solar System (planet formation seen below Dust and grains begin to clump together. Collisions between larger and larger objects produce an asteroid-sized body. Dust and grains begin to clump together. Collisions between larger and larger objects produce an asteroid-sized body. The growing body heats up and begins to melt. The growing body heats up and begins to melt. Dense molten metal particles pool together and sink towards the center of the body. Lighter silicate liquid, or magma, rises towards the surface, leaving denser solid minerals in the mantle Dense molten metal particles pool together and sink towards the center of the body. Lighter silicate liquid, or magma, rises towards the surface, leaving denser solid minerals in the mantle The result: a layered, or differentiated, body with core, mantle, and crust. The result: a layered, or differentiated, body with core, mantle, and crust.

14. Formation of the Solar System

15. Other objects in the Solar System Comets Made of rock, dust, ice, and other gases Made of rock, dust, ice, and other gases Anatomy of comets (below) Anatomy of comets (below)

16. Comets in our Solar System Halley’s Comet Halley’s Comet –1986 (76 y cyc) Comet Hale- Bopp Comet Hale- Bopp

17. Other objects in the Solar System Meteoroids, Meteors, Meteorites Meteoroids - Large bodies of rock and debris Meteoroids - Large bodies of rock and debris Meteors – meteoroids that enter Earth’s atmosphere and burn up Meteors – meteoroids that enter Earth’s atmosphere and burn up Meteorites – meteors that hits Earth’s Surface Meteorites – meteors that hits Earth’s Surface

18. Other objects in the Solar System (meteor showers below)

19. Other objects in the Solar System (meteorites) The Manicouagan Reservoir Crater in Quebec, Canada, is one of the largest meteorite craters in the world. It was formed when the Earth was blasted by a giant meteorite at the end of the Triassic period some 210 million years ago. A mass extinction of marine species occurred about the same time, and scientists believe that sky- darkening dust from the meteorite's impact may have played a role. The Manicouagan Reservoir Crater in Quebec, Canada, is one of the largest meteorite craters in the world. It was formed when the Earth was blasted by a giant meteorite at the end of the Triassic period some 210 million years ago. A mass extinction of marine species occurred about the same time, and scientists believe that sky- darkening dust from the meteorite's impact may have played a role.

20. Other objects in the Solar System (meteorites) Barringer Crater in AZ, approx. 1.2 km (4000 ft) wide. Barringer Crater in AZ, approx. 1.2 km (4000 ft) wide.

21. Other objects in the Solar System (meteorites) On June 30, 1908, a ball of fire exploded about 6 miles (10 kilometers) above the ground in the sparsely populated region, scientists say. The blast released 15 megatons of energy—about a thousand times that of the atomic bomb dropped on Hiroshima— and flattened 770 square miles (2,000 square kilometers) of forest. On June 30, 1908, a ball of fire exploded about 6 miles (10 kilometers) above the ground in the sparsely populated region, scientists say. The blast released 15 megatons of energy—about a thousand times that of the atomic bomb dropped on Hiroshima— and flattened 770 square miles (2,000 square kilometers) of forest.

22. Other objects in the Solar System Asteroids Rock similar to materials that form the planets (leftovers) Rock similar to materials that form the planets (leftovers) Most located in a belt between Mars and Jupiter Most located in a belt between Mars and Jupiter

23. Other objects in the Solar System It is thought at times in the past asteroids may have collided w/ Earth It is thought at times in the past asteroids may have collided w/ Earth It is also thought that the path of an asteroid may cross the path of Earth in the future It is also thought that the path of an asteroid may cross the path of Earth in the future –In 2004, a newly discovered 320 m asteroid 99942 Apophis achieved the highest impact probability of any potentially dangerous object. The probability of collision on April 13, 2029 is estimated to be as high as 1 in 17 99942 Apophis99942 Apophis

24. Summary Models of the solar system change with new evidence Models of the solar system change with new evidence –Geocentric / heliocentric / modern view Formation of the solar system was dependent on gravity Formation of the solar system was dependent on gravity Sun utilizes nuclear fusion Sun utilizes nuclear fusion More than just the sun and planets in our solar system More than just the sun and planets in our solar system