Planets
The smallest planet in the universe
What is Mercury
A set that includes a star and all of the matter that orbits it, including planets, moons, asteroids, comets, and other objects.
What is a solar system
The basic building block of matter. It is made of protons, neutrons, and electrons.
What is an atom
A natural object that travels around a bigger natural object.
What is a moon
This planet has signs of ancient floods, but now water mostly exists in icy dirt and thin clouds
What is Mars
A collection of thousands to billions of stars held together by gravity. We live in one called the Milky Way.
What is a galaxy
A force that pulls matter together.
What is gravity
In earth days, this is the length of a lunar moonday
What is 1 month
The biggest planet in the solar system
What is Jupiter
A cloud of dust or gas found between stars.
What is a nubula
A ball of shining gas, made mostly of hydrogen and helium, held together by its own gravity. Turning hydrogen into helium creates the energy that makes stars shine.
What is a star
This makes the moon look like it is glowing
What is the sun
The 6th planet from the sun
What is Saturn
The star in the center of our solar system.
The Sun
The gases held by gravity around Earth and around other planets. "Atmosphere" can also be used to talk about gases around stars.
What is the atmosphere
One of the first people to set foot on the moon
Who are Neil Armstrong or Buzz Aldrin
The percentage of Earth's surface covered in water
What is 70%
Rocks floating around in space. Some are the size of a pick-up truck. Others are hundreds of miles across.
What is an asteroid
The distance light travels in one year
What is a light year
The name we use when we can see all of the moon glowing
What is a full moon