Earth and Space Science: Geology, Climate, Solar System, and Universe
Earth and Space Science on this exam tests how you explain Earth's internal and surface processes, distinguish weather from climate, describe solar system motions, and interpret stars and cosmic evidence.
Earth structure and geology
Earth has a crust, mantle, and core; the outer core is liquid and generates the magnetic field. Plate tectonics explains earthquakes, volcanoes, mountain belts, and seafloor spreading. Igneous rock forms from cooling magma or lava; sedimentary rock forms from deposited materials; metamorphic rock forms under heat and pressure.
Weather and climate
Weather is short-term atmospheric condition; climate is long-term average pattern. Air masses and fronts produce weather changes. The greenhouse effect traps outgoing infrared radiation and keeps Earth warm.
Solar system
Planets orbit the Sun in ellipses, with inner rocky planets and outer gas and ice giants. Moon phases depend on the angle between Earth, the Moon, and the Sun, not on Earth's shadow except during eclipses.
Stars and the universe
Stars form from collapsing gas clouds and fuse hydrogen into helium. A light-year is a distance, not a time. Galaxies contain stars, gas, and dust; the universe is expanding, supported by redshift and cosmic microwave background evidence.
Worked example
Why does the Northern Hemisphere have summer? Earth's axis is tilted about 23.5°. When the North Pole tilts toward the Sun, sunlight strikes the Northern Hemisphere more directly and days are longer, so more energy is received. The cause is axial tilt, not distance from the Sun; Earth is actually closest to the Sun in January.
Traps
Do not blame seasons on distance from the Sun. Do not confuse weather with climate. Do not treat a light-year as time. Do not say all planets are the same type; rocky and gas planets differ in composition and size.