1. The solar system Topic # 2 Term # 2 The Local System

2. It’s a nebula thing! Looking at the needs of a solar system Everything that is needed to create stars, planets, moons are found in the clouds between stars, NEBULAS. Gases such as hydrogen, helium and dust in the form of elements such as carbon and iron are needed to begin the process.

3. Forces in space… What is needed to create the solar nebula. The gases & dust in a Nebula are made of matter. The matter of Nebulas are held together by gravity. The gravitational attraction in a nebula is very weak. The force is enough to keep the nebula together.

4. Forces in space… If gravity wasn’t enough… If gravity keeps pulling on the materials found in a nebula, it would collapse in on itself!! Pressure & temperature balance out gravity. Pressure of the particles of matter push outward against gravity.

5. Upsetting the balance. Birth of a Solar Nebula… If the balance between gravity and pressure is upset by two nebulas colliding or a nearby star exploding, it will create a Solar Nebula. This cloud of gas and dust is the basis for the formation of a solar system.

6. Building a solar system. A step by step guide… As as the solar nebula collapsed, it flattened out and began to rotate around a center of heated gas. The center of the solar nebula is the location of a protostar in its infant stage.

7. The birth theory The beginning of the planetary system. As the rotating solar nebula continued to rotate, gas and dust began to under the force of gravity collect into larger objects known as planetesimals. Some of these planetesimals developed into the core of planets while others collided with planets to create large craters.

8. The “slow” theory Looking at the Birth theory… First tiny dust grains collide to form larger clumps. This process yields solid cores roughly 10 x the mass of Earth. Their powerful gravity sucks in the gases from the disk to create a giant gas covered planet. This process could take several million years.

9. The “fast” theory Looking at the Birth Theory… Gravity causes the disk of gases & dust to collapse into dense clouds. The cloud shrinks as material falls towards the center. The rest of the clouds contract, forming a gas giant. This process could take less than a million years.

10. Where to find a winner? Looking at the different types of planets… The larger planets in our solar system are found further from the sun. The lighter gases (hydrogen & helium) were more abundant there. Closer to the nebula, it was too hot for gases to remain, this is a plausible reason why the inner planets are rocky.

11. Your new solar system! The final stage in the process… As the planets were forming, all of the extra material was being pulled towards the center. The temperature at the center became so great that nuclear fusion occurred. The explosion created a new star (our sun) which swept away all of the left over material that was in the solar nebula

12. A solar review… Review of the origin of planetary solar systems. Where is all of the material that is needed for a system found? What are the three “forces” that need to be in balance to keep the nebula together? What is a solar nebula? Illustrate. What is found at the center of a solar nebula? What is the Birth Theory? Explain both the “Slow” & “Fast” theories. What is a planetesimal? What type of planets are found near the sun? Further out from the sun? Why?