Terrestrial planets like Mercury, Venus, Earth and Mars have solid surfaces and are composed of rock. Terrestrial planets formed close to the sun according to the core accretion theory. Gas giants like Jupiter and Saturn formed farther from the sun and are largely composed of hydrogen and helium. The solar system likely started as a solar nebula from which planets accreted material.

1. Formationof the Planets Name:____________________________
1. Planetsthathave a solidsurface are called
a. Hardened
b. Terrestrial
c. Aeronautic
2. Why isit unlikelythathumanscouldsurvive onMercury?
3. Venusrotatesin
a. Antegrade
b. Protograde
c. Retrograde
4. Mars appearsredbecause the soil containsalarge amountof
a. Lead
b. Iron
c. Copper
5. Planetsthatare large anddo not have a solidsurface are
a. Gas giants
b. Liquidlummoxes
c. Softsasquatches
6. Saturn iseasilyrecognizable because of its
a. Unevenorbit
b. Ringsof gasses
c. Ringsof ice
7. Uranus ismade uplargelyof
a. Rock
b. Ice
c. Water
8. Uranus isrecognizable because it
a. Spinsbackwards
b. Spinsthe fastestof anyplanet
c. Spinshorizontally

2. 9. What happenstoplanets’orbitsaswe move furtherfromthe sun?
10. Dwarf planetsare oftenlocatedinthe ___________________________________.
11. Our solarsystemlikelystartedasa(n)
a. Asteroidbelt
b. Solarnebula
c. Expanse of emptyspace
12. Core accretiontheorysuggeststhatterrestrial planetswouldform
a. Far from the sun
b. Inside the sun
c. Nearthe sun
13. Core accretiontheorysuggeststhatgas giantswouldform
a. Far from the sun
b. Inside the sun
c. Nearthe sun
14. Whichof Earth’s layersformedof the heaviestmaterials?
a. Crust
b. Core
c. Mantle
15. The earliestatmosphere wasformedof
a. Helium
b. Oxygen
c. Hydrogen
16. How doscientistssuggestthe moonwasformed?
17. What gassesdidvolcanoesreleaseintothe atmosphere?