Give Now

A Moment of Science

What Makes the Sun Shine?

What makes the sun shine? It's a question we rarely give much thought. However, there is a scientific explanation for this commonplace phenomenon.

Vibrant sunset over ocean

Photo: Ennor (flickr)

Once a sun has formed, its light can stay shining for billions of years

What makes the sun shine?

It’s a question we rarely give much thought; it just does. However, there is a scientific explanation for this commonplace phenomenon.

The sun, like every star, was created by the effect of gravity.

Originally, all the matter that makes up the sun was in the form of dust and gas floating in space. This dust was composed of many different elements, with the most prevalent being hydrogen.

Over time, the force of gravity caused the dust to lump together; the larger the lump became, the more dust it accumulated. These lumps continued to grow and connect, until a few billion years later a titanic mass was formed, called a proto-star.

Soon, the gravitational attraction of the proto-star bagan to pull its parts tighter and tighter together. As the proto-star became larger, the more powerful this pull became, thus the tighter it compacted.

This continued until the proto-star became so tightly packed that hydrogen atoms began to fuse with each other, releasing a blast of energy containing a new element, helium.

At this point the proto-star has become an actual star, crushing hydrogen into helium in an ongoing controlled explosion. The outward force of the explosion keeps the star from contracting too small, while the inward crush of gravity keeps it from blowing apart.

Once this equilibrium is reached, a star such as our own sun can stay balanced and shining for literally billions of years.

Stay Connected

What is RSS? RSS makes it possible to subscribe to a website's updates instead of visiting it by delivering new posts to your RSS reader automatically. Choose to receive some or all of the updates from A Moment of Science:

Support for Indiana Public Media Comes From

About A Moment of Science

Search A Moment of Science