Earth and Its Atmosphere Quiz

Earth and Its Atmosphere

• Earth formed approximately 4.5 billion years ago within the inner Solar nebula.
• Earth's formation involved four stages: differentiation, cratering, flooding, and slow surface evolution.
• Differentiation led to the separation of dense elements forming Earth's core.
• Cratering describes Earth's early bombardment by debris.
• Flooding occurred with molten rock and water covering the Earth's surface.
• Slow surface evolution is the current stage of Earth's development characterized by geological processes and erosion.

Types of Seismic Waves

• Seismic waves are used to study Earth's interior.
• P-waves (primary waves or compressional waves) are the first to arrive, and are faster.
• S-waves (secondary waves or shear waves) are second to arrive, and are slower.
• S-waves only travel through solids.
• The differing speeds and paths of seismic waves reveal the composition and structure of Earth's interior.

Earth's Interior

• The crust is a solid outer layer mostly composed of granite and basalt.
• The mantle is the largest layer, also solid, made of silicon-rich rock.
• The outer core is liquid, primarily an iron alloy.
• The inner core is solid, also primarily composed of iron.
• Temperature and pressure increase toward the center of Earth.

Earth's Magnetic Field

• Earth's magnetic field is generated by a dynamo mechanism involving convection and rotation of molten iron in the outer core.
• The magnetic field is tilted relative to the Earth's rotation axis.
• Magnetic field polarity flips roughly every few million years.
• The magnetic field protects Earth from harmful solar radiation.

Tectonic Plates

• Earth's crust is broken into numerous tectonic plates that move relative to one another.
• Some plates are oceanic (denser, basaltic); continental plates are less dense granite.
• Plate movement causes earthquakes, volcanic activity, and mountain formation.
• Plate movement relative to each other leads to either collision or separation.

Earth's Atmosphere

• Earth's atmosphere is composed primarily of nitrogen and oxygen.
• The atmosphere has distinct layers, each with different temperatures and densities.
• The troposphere is the lowest layer containing most weather; Stratosphere is where the ozone layer resides; Mesosphere is where most meteors burn; Thermosphere where aurora occur; and the Exosphere is the outermost layer, where molecules gradually escape into space.
• The ozone layer protects Earth from harmful ultraviolet radiation.

Space Weather

• Space weather refers to changes in the space environment affecting human activity.
• The Sun's activity, such as coronal mass ejections and solar flares, can impact Earth's magnetosphere.
• Earth's magnetic field deflects most high-energy particles.
• Space weather can disrupt communications, navigation systems, and electrical grids.

The Moon

• The Moon orbits Earth.
• The Moon's orbit and position relative to Earth and Sun affect Earth's tides.