Life Cycle of the Sun: Lesson for Kids

Instructor: Corrie Boone

Corrie holds master's in elementary education, taught elementary ESL in the public schools for 5 years, and recently was teaching EFL abroad.

Do you know how old the Sun is or how long it will live? Although the Sun isn't something you typically think of as living, the Sun, like other living things, has a life cycle. Today we'll look at the stages in the Sun's life cycle.

The Center of Our Solar System

The Sun is the biggest and most important star in our solar system - without it, there would be no life on Earth. However, while the Sun is the center of our solar system, it is simply one of a countless number of stars in the universe. And, like all stars, the Sun has a life cycle. Let's take a look at the stages of the Sun's life cycle.


In the Beginning

The Sun began forming about 5 billion years ago. Back then, our solar system was just a cloud of dust, molecular gas and other particles. Then something happened, scientists aren't exactly sure what it was, that caused this cloud to collapse. Gravity pulled most of the matter to the center, forming a very dense, very hot ball of mass.

In this stage, the Sun was a protostar, which is the first stage in the life cycle of stars, before nuclear fusion happens. Nuclear fusion is the process of hydrogen, the main component of the Sun, being converted (burned) into helium. Once nuclear fusion begins, then the protostar becomes a star. Our sun began burning hydrogen about 4.6 billion years ago. This is the moment we consider the Sun to have been born.

A protostar in space.

The Main Sequence

The next stage in the life cycle of our Sun is the main sequence. When you think of a star, like the ones you see at night shining in the sky, they are in this stage. The star is burning hydrogen, causing it to shine brightly.

The Sun, like other stars, will spend most of its life in this stage. Gravity wants to shrink the star, while heat (nuclear fusion) wants to make it bigger. But the two together form a nice balance that keeps the Sun in this stage, where it will remain for about 5.4 billion more years until it burns all of its hydrogen. When that happens, it will leave the main sequence stage of its life cycle.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account