PHS 119, Week 4: Planetary Science

Terrestrial Planets

Mercury, Venus, Earth, and Mars; rocky with thin atmospheres

Jovian Planets

Jupiter, Saturn, Uranus, and Neptune; gas giants with thick atmospheres

Atmosphere

Gas layer surrounding a planet, crucial for shielding and regulating heat

Greenhouse Effect

Atmospheric gases trapping heat near a planet's surface

Troposphere

Layer closest to a planet's surface where clouds form

Stratosphere

Layer with ozone to block harmful UV radiation

Mesosphere

Layer where meteors are seen

Thermosphere

Thinnest layer blocking x-rays and displaying aurorae

Magnetic Fields

Shaped like bar magnets, shield planets from solar winds

Solar Winds

High-energy charged particles from the sun

Aurora Borealis

Light emitted when solar rays collide with atmospheric gas molecules at the North Pole

Aurora Australis

Light emitted when solar rays collide with atmospheric gas molecules at the South Pole

Reflectivity

Ability of a planet's surface to reflect sunlight

Hydrogen and Helium

Light gas molecules found in planet atmospheres

Silicate Rock

Material surrounding iron-nickel core in terrestrial planets

Ammonia Clouds

Clouds formed from frozen methane in Uranus and Neptune's atmospheres

Great Red Spot

Vortex on Jupiter lasting centuries due to no solid surface

Radiation Belt

Trapped charged particles spiraling along a planet's magnetic field lines

Reflective Colors

Lighter colors reflect more sunlight, influencing planet temperatures

Venus Greenhouse Effect

Exceptionally strong, raising surface temperature to 447 degrees celsius

Carbon Dioxide Atmosphere

Thin atmosphere on Mars due to weak gravity

Jupiter's Cloud Bands

Striped pattern due to fast rotation and different speeds of gases

Magnetic Field Production

Generated by motion of conducting interiors

Vortex Formation

Interaction of gas bands creating long-lasting storms

Jovian Atmosphere

Contains thermospheres, stratospheres, and tropospheres

Jovian Clouds

Three distinct cloud decks, with ammonia at the top

Jovian Atmosphere Composition

Primarily hydrogen and helium gases

Convective Motion

Movement in liquid metal caused by fast planet rotation

Radioactive Decay

Source of interior heat in terrestrial planets

Lithosphere

Rigid upper layer including crust and upper mantle

Asthenosphere

Pliable layer below lithosphere in mantle

Plate Tectonics

Movement of lithosphere across asthenosphere

Late Heavy Bombardment

Period of frequent large impacts in early solar system

Volcanism

Process of volcanic activity on planets and moons

Erosion

Surface process caused by wind, water, or glaciers

Tectonics

Stretching or compression of a planet's lithosphere

Atmospheric Pressure

Pressure exerted by a planet's atmosphere at its surface

Venus

Experienced a runaway greenhouse effect about a billion years ago

Carbonates

Form in rocks, locking up much of a planet's CO2

Atmospheric CO2

Earth has over 30 times more CO2 in rocks than in the atmosphere

Water Vapor

Initiated the greenhouse effect on Venus due to evaporation

Volcanically Active

Current state of Venus with ongoing volcanic activity

Mars Diameter

Mars is about half the size of Earth in diameter

Mars Atmosphere

Composed of 95% carbon dioxide with very low air pressure

Mars Seasons

Experience extreme temperature variations due to lack of greenhouse effect

Mars Moons

Phobos and Deimos are small, non-spherical moons of Mars

Earth's Moon Gravity

1/6th the gravity strength of Earth, 1/4th Earth's diameter

Moon Formation

Formed from debris of a collision with Earth, trapped in orbit

Jupiter's Moons

Galilean satellites, including Io, Europa, Ganymede, and Callisto

Titan

Saturn's largest moon with Earth-like atmospheric pressure

Comet Tails

Dust tail follows comet's motion, ion tail points away from the sun

Asteroid Belt

Located between Mars and Jupiter, contains millions of asteroids

Meteorites

Rocks that survive Earth's atmosphere impact from meteoroids

Kuiper Belt

Beyond Neptune's orbit, home to dwarf planets like Pluto

Oort Cloud

Spherical region far from Earth with billions of comets

Solar System Formation

Began as a spinning gas nebula, leading to planet formation