The Universe EQ:

What is The Universe? The universe is HUGE!!! It is made up of stars, galaxies, planets, moons, comets, meteoroids, gas, and dust (but it’s mostly made of empty space). The universe formed about 14 billion years ago.

The Hierarchy of organization Moving from left to right! Hierarchy of Organization smallest largest meteoroids universe planets solar systems moons galaxies stars

We are Here

GALAXIES A collection of billions of stars held together by gravity.

Galaxies Classified by shape: spiral, elliptical and irregular.

Galaxies Earth is in a spiral galaxy called the Milky Way.

We are Here

Solar System A collection of large and small bodies that orbit a central star.

Solar Systems Consists of at least one star, planets, moons, asteroids, dwarf planets, and comets.

Stars Huge spheres of ionized gas held together by gravity.

Stars Creates and gives off heat and light. Classified by size.

We are here

Planet A round, celestial object that orbits around a star. There are eight planets in our solar system.

Terrestrial Planets Small, dense, rocky planets with a metal core Thin atmosphere Mercury, Venus, Earth, Mars

Gas Giant Planets Large, gaseous, low density with a rocky core Thick atmosphere Jupiter, Saturn, Uranus, Neptune

Kilometers (Km) 1Km = 1000 meters Useful when measuring the distance between a planet and its moon.

Astronomical Units (AU) 1 AU = 149,597,871 Km Equal to the average distance between Earth and the Sun. Useful to measure the distance between planets.

Light Year (ly) 1 ly = 9.46 trillion Km Equal to the distance that light can travel in one year in a vacuum. Useful to describe the distance between stars.

Parsec (pc) 1pc = 3.26 ly Used to measure enormous distances like the distance between galaxies.