ASTR 011 Spring 2025 Final Exam Study Guide - Vocabulary

Flashcards for ASTR 011 Spring 2025 Final Exam Study Guide, focusing on vocabulary terms from the lecture notes.

Terrestrial Planets

The inner, rocky planets of the solar system: Mercury, Venus, Earth, and Mars.

Giant Planets

The outer, gaseous planets of the solar system: Jupiter, Saturn, Uranus, and Neptune.

Conservation of Angular Momentum

As a giant cloud of gas and dust collapses, the cloud spins faster causing a spinning sphere of gas and dust to become a flattened, rotating disk.

Proto-planetary Disk

The flattened disk of gas and dust around a young star in which planets form.

Solar Nebula

The flattened cloud of gas and dust from which our planetary system formed.

Planetesimals

Precursors of planets; small bodies of rock and metal (or ice) that coalesce to form planets.

Differentiation

A system that has different properties at different locations (e.g., rocky inner planets and gaseous outer planets).

Radioactive Decay

The process by which unstable atomic nuclei spontaneously transform into more stable nuclei, resulting in a change in the number of protons and neutrons.

Half-life

The time it takes for half of the original parent atoms in a radioactive sample to decay into daughter atoms.

Tectonism

Geological activity and deformation of a planet's crust (moving crustal plates).

Volcanism

The eruption of molten rock (magma) onto the surface of a planet.

Heavy Bombardment Period

The first billion years of the Solar System when almost all cratering occurred.

Erosion

The wearing down or removal of surface materials by wind, water, or other geological processes.

Seismology

The study of earthquakes and the propagation of seismic waves to investigate the interior of a planet.

Lithosphere

The rigid outer layer of a planet, composed of the crust and the uppermost part of the mantle, broken into plates.

Convection

The rising and falling of hot and cold material within a planet's mantle or atmosphere.

Dynamo Effect

The process by which the rotation of a planet's liquid outer core generates a magnetic field.

Magnetosphere

The region around a planet where its magnetic field dominates and deflects charged particles from the solar wind.

Solar Wind

A stream of charged particles, mostly protons and electrons, flowing outward from the Sun.

Aurorae

The northern and southern lights, caused by charged particles from the solar wind colliding with the atmosphere.

Coriolis Effect

An effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation.

Hadley Cells

Smaller atmospheric convection cells broken from the larger atmospheric convection cells due to the rotation of the Earth and the Coriolis effect

Greenhouse Effect

The warming of a planet's surface due to the absorption and trapping of infrared radiation by certain gases in the atmosphere.

Escape Velocity

The minimum speed an object must have to escape the gravitational pull of a planet.

Primary Atmosphere

The initial atmosphere of a planet, typically composed of hydrogen and helium.

Secondary Atmosphere

A later atmosphere formed after the planet's initial atmosphere is lost, typically through volcanism and comet impacts; it is composed of gases like CO2, N2, and H2O.

Troposphere

The lowest layer of Earth's atmosphere, where temperature decreases with altitude and weather occurs.

Stratosphere

A layer in Earth's atmosphere located above the troposphere, where temperature increases with altitude due to ozone absorption of UV light.

Mesosphere

The atmospheric layer above the stratosphere, where temperature declines with altitude.

Thermosphere

The outermost layer of Earth's atmosphere (also called the ionosphere), where ultraviolet radiation and solar wind ionize atoms, heating up the layer.

Giant Impact Hypothesis

The prevailing theory for the Moon's formation, where it formed in a large collision between Earth and a Mars-sized protoplanet.

Synchronous Rotation

When the rotation rate of a moon or planet equals its orbital rate (revolution rate).

Maria

Dark, smooth patches on the Moon formed from hardened lava lakes.

Shield Volcanoes

A broad, domed volcano with gently sloping sides, characteristic of volcanoes on Mars and Venus.

Lava Domes

Rounded, bulbous masses of lava that typically form when felsic lava erupts onto the surface.

Plutinos

Large Kuiper Belt objects near Pluto’s size.

Cryovolcanism

A type of volcanism where the 'magma' is water or other volatile substances instead of molten rock.

Kepler's Laws

Three scientific laws describing the motion of planets around the Sun.

Shepherd Moons

Small moons that orbit near or within planetary rings, helping to confine and maintain the ring structure through gravitational herding.

Asteroid Belt

The region between Mars and Jupiter where most asteroids are found.

Comets

Icy planetesimals found beyond the planets in elliptical orbits.

Kuiper Belt

A region beyond the outer planets filled with icy objects.

Oort Cloud

A spherical region surrounding the Solar System, hypothesized to be the source of long-period comets.

Dirty Snowballs

A description of comets as composed of a nucleus which is composed of an ice/rock mix.

Plasma

Gas that is completely ionized.

Helioseismology

The study of the Sun's interior using sound waves that vibrate throughout the Sun.

Radiative Transfer

Energy in the form of gamma ray photons are emitted as byproducts of fusion in the core.

Opacity

The degree to which matter blocks the flow of photons through it.

Granulation

The rising and falling plasma blobs we see as convection on the surface of the Sun.

Photosphere

The layer of the Sun that we see when we take a photo of the Sun, it is the surface of the Sun.

Limb darkening

Because we look through less material at the edges, the Sun appears to have a sharp edge.

Differential Rotation

Different parts of the Sun rotate at different speeds.

Solar Wind

The solar wind is composed of charged particles, hydrogen and helium nuclei, as well as electrons, that flow away from the Sun through coronal holes.

Solar Flare

A sudden eruption of energy in the solar atmosphere.

Coronal Mass Ejection

A sudden release of plasma and magnetic field from the solar corona.

Hydrostatic Equilibrium

The outward pressure of light (radiation) = inward pressure due to the force of gravity.

Fusion

Two small nuclei combine to make a larger atom.

Fission

When a large atom splits into 2 smaller atoms.

Annihilation

When a particle and its antiparticle meet, both the particle and antiparticle are completely destroyed and completely turn into energy.