Chapter 1: A Modern View of the Universe - Vocabulary Flashcards

Vocabulary flashcards covering fundamental astronomical terms, scale of the universe, cosmic history, and celestial movement based on Chapter 1.

Cosmic Address

The sequence of structure levels marking Earth's position in space: Earth, Solar System, Milky Way Galaxy, Local Group, Local Supercluster, and the Universe.

Star

A large, glowing ball of gas that generates heat and light through nuclear fusion.

Planet

A moderately large object that orbits a star and shines by reflected light; it may be rocky, icy, or gaseous in composition.

Moon (or Satellite)

An object that orbits a planet.

Asteroid

A relatively small and rocky object that orbits a star.

Comet

A relatively small and icy object that orbits a star.

Solar (Star) System

A star and all the material that orbits it, including its planets and moons.

Nebula

An interstellar cloud of gas and/or dust.

Galaxy

A great island of stars in space, all held together by gravity and orbiting a common center.

Universe

The sum total of all matter and energy; that is, everything within and between all galaxies.

Light-Year

The distance that light can travel in $1$\text{ year}, which is about $10$\text{ trillion kilometers} ($6$\text{ trillion miles}).

Cosmic Calendar

A scale on which the entire history of the universe is compressed into $1$\text{ year}.

Nuclear Fusion

The process powering stars, in which energy is released and chemical elements heavier than hydrogen and helium are manufactured.

Ecliptic Plane

The flat plane defined by Earth's orbital path around the Sun.

Expansion of the Universe

The phenomenon in which space itself expands, causing distant galaxies outside our Local Group to move away from us, with more distant galaxies receding at faster speeds.