Astronomy Chapter 6 Vocabulary
Seismograph
A device used to record and measure seismic waves, such as those produced by earthquakes
Rille
A winding crack or depression in the lunar surface caused by the collapse of a solidified lava tube
Solar wind
An outward flow of particles (mostly electrons and protons) from the Sun
Highlands
Heavily cratered, mountainous regions of the lunar surface
Coronal mass ejection
Large volumes of the high-energy gas released from the Sun's corona
Mare (maria)
Latin for "sea"; a large relatively crater-free plain on the Moon
Northern lights (aurora borealis)
Light radiated by atoms and ions in Earth's upper atmosphere due to high-energy particles from the Sun and seen mostly in the northern polar regions
Spring tide
The greatest daily difference between high tide and low tide, occurring when the Moon is new or full
Ionosphere (thermosphere)
Region of Earth's atmosphere, above the mesosphere, in which sunlight ionizes many atoms
Core
The central portion of an astronomical object
Core (of the Earth)
The central solid iron region and the liquid iron region surrounding it inside the Earth
Synchronous rotation
The condition when a moon's radiation rate and revolution rate are equal or when a planet's rotation rate equals its moon's revolution rate
Dynamo theory
The generation of a magnetic field by circulating electric charges
Continental drift
The gradual movement of the continents over the surface of Earth due to plate tectonics
Capture theory
The idea that the Moon was created at a different location in the solar system and subsequently captured by Earth's gravity
Mesosphere
The layer in Earth's atmosphere above the stratosphere
Neap tide
The least change from high to low tide during the day; it occurs during the first and third quarter phases of the Moon
Troposphere
The lowest level of Earth's atmosphere
Ozone layer
The lowest stratosphere, where most of the ozone in the air exists
Plate tectonics
The motions of large segments (plates) of Earth's surface caused by convection motions in the underlying mantle
Mantel
The portion of a terrestrial planet located between its crust and core
Regolith
The powdery, lifeless material on the surface of a moon or planet
Planetary differentiation
The process early in the life of each planet whereby denser elements sank inward and lighter ones rose
Seafloor spreading
The process whereby magma upwelling along rifts in the ocean floor causes adjacent segments of Earth's crust to separate
Magnetopshere
The region surrounding the earth or another astronomical body in which its magnetic field is the predominant effective magnetic field
Ejecta blanket
The ring of material surrounding a crater that was ejected during the crater-forming impact
Stratosphere
The second layer in Earth's atmosphere, directly above the troposphere
Crust
The solid surface layer of some astronomical bodies, including the terrestrial planets, the moons, the asteroids, and some stellar remnants
Cocreation theory
The theory that the Moon formed simultaneously with Earth and in orbit around it
Collision-ejection theory
The theory that the Moon was created by the impact of a planet-sized object with Earth; presently considered the most plausible theory of the Moon's formation
Tidal force
The tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational force exerted by one body on another is not constant across it; the nearest side is attracted more strongly than the farthest side.
Convection
The transfer of energy by moving currents of fluid or gas containing that energy
Van Allen radiation belts
Two flattened, doughnut-shaped regions around Earth where many charged particles (mostly protons and electrons) are trapped by Earth's magnetic field
Seismic waves
Vibrations traveling through or around an astronomical body usually associated with earthquake-like phenomena