The Solar System

Hostile environments

Can create reactions within characters.

Orrery

A mechanical model of the solar system that predicts positions and motions of planets and moons.

Voyager 1

Spacecraft that flew past Neptune in 1989.

Voyager 2

Spacecraft that took footage of the planets.

Loss of the ability to travel between stars

Can cause civilizations to fall.

Moons

Natural satellites that orbit planets.

Exoplanets

Planets found outside of our solar system.

Gravitational pull

The force that pulls objects with mass toward each other.

Indirect form of planet detection

A method of identifying a planet by observing its gravitational effects on its host star.

Transit method

A technique where a planet passing in front of a star causes a slight dimming in the star's brightness.

Radial velocity method

Detects a star's wobble caused by a planet orbiting it.

Asteroid belt

The region between Mars and Jupiter filled with numerous asteroids.

Kuiper belt

Another asteroid belt located beyond Neptune. It is made out of ice.

Prograde direction

The direction in which the planets orbit the Sun, which is anticlockwise.

Inner planets

Mercury, Venus, Earth, and Mars, which are closer to the Sun.

Venus

Known as the evening star to Earth.

Giant planets

Jupiter, Saturn, Uranus, and Neptune, which are larger and generally farther from the Sun.

Ice giant planets

Uranus and Neptune, which are primarily composed of ice and gas.

Formation of planets

Planets are formed from material around the Sun, including asteroids and comets.

Surface-level planets

Planets with solid or liquid surfaces, such as terrestrial planets.

Gas giants

Planets that are primarily composed of gas with no defined surface.

Planetary surface

Where a planet's solid or liquid material meets the atmosphere or outer space.

Exoplanet surface

The point in the atmosphere of an exoplanet where pressure reaches 1 bar.

Asteroids

Rocky bodies in space that are generally far apart from one another.

Orbital resonance

A location where planets affect the orbits of other celestial bodies.

Uranus tilt

Uranus is tilted on its side compared to other planets.

Solar system features

All large bodies in near-circular orbits in a prograde direction, consisting of terrestrial and gas giants with an asteroid belt in between.

Earth's moon

Unusually large moon formed from a giant impact with Theia.

Lunar phases

The changing appearance of the Moon as it orbits Earth.

Waxing moon

The phase of the moon where it appears fuller and rises later each night.

Waning moon

The phase of the moon that becomes less visible and sets later each day.

Solar eclipse

Occurs during a new moon when the moon is between Earth and the Sun.

Phases of the moon

Determined by the relative positions of the Sun, Moon, and Earth.

Surface gravity

A measure of the weight of an object at the surface of a planet.

Terraforming Mars

The process of modifying Mars' environment to make it habitable, considering gravity.

Circulatory challenges on Mars

High surface gravity could require larger hearts for blood circulation.

Respiration on Mars

Breathing could be more challenging due to higher gravity.

Mobility in higher gravity

Movement may be slower and energy-intensive, favoring shorter bursts.

Definition of a planet

According to IAU, a planet is an object in orbit around the Sun, has sufficient mass to be round, and has cleared its orbit neighborhood.

New Horizons

Spacecraft that took pictures of Pluto.

Pluto's surface gravity

Only six percent of Earth’s surface gravity.

Harry Harrison's Deathworld trilogy

Literature that explores the concept of planets in extreme conditions.

Larry Niven's Known Space

A setting that features various concepts of space travel and planets.

Warhammer

A popular universe that includes themes of planets and interstellar travel.

The Expanse

A series known for its realistic portrayal of space and planets.

Surface of Eris and Haumea

Dwarf planets with solid surfaces considered in planetary studies.

Phases of a planet's moon

The different visible stages of a moon's orbit.

Mars' terraforming challenges

Surface gravity and carbon dioxide levels must be considered.

Asteroid dispersion

Asteroids are more dispersed than often portrayed in media.

Lunar orbit period

The Moon takes about 27.3 days to complete an orbit around Earth.

Asteroids in the solar system

Minor planets that do not coalesce into planets due to gravitational influences.