The Sun in Space
Our planet, Earth, rotates around the Sun along with seven other planets. The Sun is so huge that its gravity pulls all of the planets around it. Asteroids, moons, and comets also orbit around the Sun. The Sun is so big that 1,000,000 Earths could fit inside it!
The Sun is very important to the Earth and the people, animals, and plants that live on it. The Sun provides light and heat, two important forms of energy. Energy is what gives things the ability to do work and move. A car gets energy from gasoline. You get energy from food. Most energy on Earth comes from the Sun.
Plants Need the Sun to Grow
Plants don’t move around, but they do need energy to grow. Plants use energy from the Sun in a process called photosynthesis. Photosynthesis uses light energy from the Sun, water, and carbon dioxide to create a sugar called glucose. Oxygen is also created during photosynthesis. These two things are very important to people and animals. We eat glucose and breathe oxygen. Without the Sun, plants, animals, and people would all be in trouble.
The Water Cycle
The Sun is also what provides energy for the water cycle. The heat energy from the Sun heats up the water on the surface of the ocean. This evaporates the water, and it becomes water vapor. Water vapor is a gas. It floats up into the air to form clouds. In the clouds, the water vapor condenses meaning it collects back into liquid water droplets. When the water droplets are too heavy to stay in the cloud they fall down as rain. This is called precipitation. If it is very cold, the liquid water will fall as snow or hail.
Without the Sun to evaporate the water from the oceans, the water cycle wouldn’t happen, and plants wouldn’t get the water they need to grow. The water cycle happens over and over again every day: evaporation, condensation, precipitation, evaporation, condensation, precipitation… And it all starts with the Sun.
Linking Energy Back to the Sun
You may be thinking to yourself, there are lots of types of energy that don’t come from the Sun. Wind power comes from the wind, not the Sun. Well, that just isn’t true. Wind does come from the Sun. The Sun heats the air on Earth unevenly. The area around the equator regularly gets the most heat, and the ends of the Earth get the least heat. These differences lead to air molecules moving around. We call air molecules moving wind.
How about gasoline? Gasoline is a product of oil that comes out of the ground. This oil comes from the plants and animals that lived millions of years ago. These plants grew using energy from the Sun. The animals grew by eating the plants. Even oil from deep underground got its energy from the Sun!
Energy that Isn’t From the Sun
There is one other source of energy on Earth. It is the Earth itself. When the Earth was forming, rocks were colliding with each other in space. All of the energy from these collisions is trapped inside the Earth as heat energy. The inner layers of the Earth are incredibly hot.
Heat from the inner layers of the Earth reaches deep pockets within the ocean. Plants and animals living in these pockets get energy from this heat. For many years, scientists didn’t even know these creatures existed. They are too deep under the ocean to get energy from the Sun, but they are still able to live and grow.