The answer is "moons, planets, comets."

Star - A ball of hydrogen gas held together by gravity. The central core of a star is extremely hot and produces energy. Some of this energy is released as visible light, which makes the star glow.
Planet - a celestial body moving in an elliptical orbit around a star
Solar System - a collection of planets and their moons in orbit around a star, together with smaller bodies in the form of asteroids, meteoroids, and comets.
Galaxy - a system of millions or billions of stars and the solar systems within them, together with gas and dust, held together by gravitational attraction

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "a galaxy."

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is, "the universe is expanding."

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "As distance between the sun and each planet increases, so does the distance between each planet."
Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "The Milky Way." Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "older and larger."

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "a spectrometer."

Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)

The answer is "the universe, Andromeda Galaxy, the Moon." Distances in the universe are so vast that they can be difficult to comprehend. We measure distances in space using light years. A light year is about 6 trillion miles, the distance light travels in one Earth year. 

We live on Earth, a planet in a solar system that orbits our sun. Our solar system is only part of a much larger system of many billions of stars called the Milky Way Galaxy. The Milky Way is shaped like a disk with concentrations of brighter stars and clouds of gas shaped like a whirlpool. The Milky Way is only one galaxy of many billions of galaxies in the universe.

In order from smallest to largest, some important terms to remember are: planets and stars, solar systems, galaxies, the universe. Each term is a component of the next. (Aside from planets and stars which are both different components of solar systems.)