The Sun, Earth, and Moon

Measuring Temperatures

Earth• Earth is the third planet from the sun.• Earth is often called the "Water Planet"

because it is the only planet in our solar system which has liquid water on its surface. About 70% of the surface of Earth is covered by water! The other part of Earth is made up of continents and islands which we live on. Because Earth has so much water, plants and animals can live on Earth.

• Earth is the only planet in our solar system which has all the conditions that are needed for us to live on it. There is plenty of water, air, and land. Different parts of Earth have different temperatures, but plants, animals, and humans can live in almost all areas of Earth.

Earth spins very quickly compared to other planets. It only takes Earth 24 hours to spin around its axis one time. One Earth day is 24 hours long! Earth orbits the sun in 365 days! This makes one Earth year 365 days long!

• Axis- the center around which something rotates• Orbit- the (usually elliptical) path described by one celestial body in its

revolution about another• Celestial- of or relating to the sky

WordsYou ShouldRecognize

Moon

Earth has one moon which we call "The Moon". Its surface has many craters on it from where meteorites have hit it. It has many volcanoes on it which do not erupt anymore. We can see the moon at night without using a telescope. It is the closest space object to our planet.

The moon is the earth’s only natural satellite, which means it orbits the earth. Its average distance from the earth is 384,403 km. The moon always keeps one side turned toward the earth and the other side turned away from the earth. This type of motion is called synchronous rotation. The side turned away from the earth is called the moon’s dark side, even though it is lit half of the time.

The moon is not always the same distance from the earth. It is not ecliptic. The moon has a noticeable effect on the earth in the form of tides, but it also affects the motion and orbit of the earth.

Sun

The sun is very, very big. More than one million planet earths could fit inside of the sun! Earth seems very big to us. Imagine how big the sun must be! Our sun is called a yellow dwarf star. This means it is only a medium-sized star!

The sun is made of gases called hydrogen and helium. It is always burning and is very hot. The outside of the sun is 11,000 degrees Fahrenheit. An extremely hot day on earth is only 100 degrees Fahrenheit. The sun's surface is about 100 times as hot as the hottest day on earth! Our sun is very important to us. It gives us light and heat. Without light and heat we would not be able to live.

Temperatures By Season