Chapter 6 Quiz: Olivia Ward

1. What does the solar system look like?
   
   Our solar system is made up of planets and their moons, asteroids, and comets that orbit the sun. The planets are little compared to the distance between them. Every planet has its own characteristics, but there are definite patterns that occur throughout. The planets include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto is considered a dwarf planet.
   
   
2. What features of our solar system provide clues to how it formed?
   
   There are four major clues that give us clues about the solar system's formation. The sun, planets, and large moons generally rotate and orbit in very organized ways. The planets can be divided into two groups: terrestrial and jovian. The solar system contains a large amount of asteroids and comets, some even being large enough to be considered dwarf planets. Last, but  not least, there are some notable exceptions to these patterns.
   
3.  What theory best explains the features of our solar system?
   The Nebular Theory best explains our solar system. A rotating nebula contracted which caused the cloud to heat, flatten, and spin faster. This resulting in a spinning disk of dust and gas. The gas, H and He, remained gaseous, but the other material further condensed into "seeds" for building planets. These "seeds" collided and merged together. The larger merged formed attracted smaller ones. The nebula was then cleared by solar winds which blew the remaining gas into interstellar space.
   
   
   
4. Where did the solar system come from?
   
   The solar system came from a cloud of gas. This cloud was produced through galactic recycling through many generations of stars. The gas consisted of 98% H and He, and 2% of all of the other elements.
   
5. What caused the orderly patterns of motion in our solar system?
   
   Our solar system started out as a spinning disk of gas and dust, a collapsing gas cloud. The orderly motions that we see cam from the orderly motions of that spinning disk.
   
6. Why are there two major types of planets?
   
   In the inner solar system, the high temperatures caused terrestrial planets to form. Only metal and rock could condense, which explains composition of terrestrial planets. Because of the cool temperatures of the outer solar system, only jovian planets could form. The temperatures allowed ices to condense, as well as metal and rock.
   
   
7. Where did asteroids and comets come from?
   
   Asteroids are the rock leftovers that planetesimals of the inner solar system. Comets are the icy leftovers of planetesimals of the outer solar system. Asteroids are believed to be pieces of a broken planet while comets are chunks of rock, dust, ice, and frozen gases.
   
   
8. How do we explain the existence of our Moon and other exceptions to the rules?
   
   Most of the exceptions to these rules likely cam from collisions or close encounters with leftover planetesimals. Our Moon is most likely the result of a giant impact between a Mars-size planetesimal and Earth.
   
   
9. When did the planets form?
   
   The planets formed 4.6 billion years ago. This was determined by radiometric dating of the oldest meteorites.
   
   
10.  How do we detect planets around other stars?
    
    We are able to detect extrasolar planets by indirectly observing the planet's effects on the star it orbits. Most discoveries have been made by using the Doppler technique. Doppler shifts reveal the gravitational tug of a planet on a star.