How Energy Moves Within the Sun

Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will describe how energy is carried from the inner reaches of the Sun, through the radiative zone, then the convective zone, and finally into space.

Energy Transport

How is energy transported to light up the light bulb in your room? Well, depending on the source of energy, it may go something like this.

First, giant machines dig through the ground to dig up coal. That coal, an energy source, is dumped into trucks or railcars. Then it's taken to a coal plant where its energy is converted into electricity. This then travels via wires to your home to light up that light bulb. There are clearly lots of steps involved in what seems like a simple task: flipping the switch.

How energy is transported in the Sun to light up the Earth, to eventually give someone the simple pleasure of warmth on their skin on a cool day, will be explained in this lesson.

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Solar System, Galaxy, & Universe: Definitions & Difference

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:01 Energy Transport
  • 0:45 The Radiative Zone
  • 2:57 The Convective Zone
  • 4:37 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

The Radiative Zone

The temperature of the Sun, the surface of the Sun to be exact, is 5800 Kelvin. Compare that to the temperature at the center of the Sun, about 16 million Kelvin. You know that heat always flows from hot areas to cool areas. Thus, heat from this incredibly hot center of the Sun moves towards its cooler surface and from there, into space.

The extremely hot center of the Sun is its core, where it generates its energy through nuclear fusion. Because it's so hot over there, gamma ray photons are found at its center. Photons are bundles of electromagnetic radiation. Short-wavelength, high-energy photons, like gamma rays, are emitted at higher temperatures than longer-wavelength, lower-energy photons.

From the core, these high-energy gamma ray photons will not travel straight out into space. If that happened, they'd escape into space two seconds after being emitted. Such a quick exit from the core is not possible because the gamma rays will be deflected and scattered every which way by electrons and atomic nuclei located at the core. Think of it as one gigantic and awfully long-lasting bumper car match where the photons try to escape the rink, but the electrons and nuclei constantly bump the photons in random directions.

But with time, the gamma ray photons will make their way outwards, towards the cooler areas of the Sun. As they do so, their high energy will be converted into several photons of lower energy, like a high-value currency can be converted into several units of a lower-value currency.

The outward motion of this energy from the core occurs in the form of radiative diffusion, and thus, astronomers refer to one of the inner parts of the Sun nearest the core as the radiative zone, the area inside a star, like the Sun, where energy flows outwards as photons, which remember, are little packets of electromagnetic radiation.

In the process of radiative diffusion, photons are emitted in one place and absorbed in another, thereby transporting energy between two points.

The Convective Zone

In this way, the energy flowing outwards from the core as radiation will eventually get to more outer layers of the Sun. Here, as you already know, the gas is cooler. This lower temperature means the gas here isn't completely ionized. For us, this means that such a layer of gas isn't really transparent to radiation.

Like you can't see through an opaque window, energy can't get past an opaque gas very well. Therefore, the energy flowing outwards from the Sun's interior will get backed up as if behind a dam.

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 now
Create an account to start this course today
Used by over 30 million students worldwide
Create an account