Chromosphere: Definition & Properties

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: The Solar Corona & Solar Wind

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 The Chromosphere
  • 0:41 What are Spicules?
  • 2:18 Why the Pinkish-Red Color?
  • 3:09 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
Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will explore some of the interesting features of the second layer of the sun's atmosphere, the chromosphere, including spicules and its pinkish hue.

The Chromosphere

What's pinkish-red and invisible? It's a layer of the sun this lesson is going to cover in some detail. It's ordinarily invisible from Earth, unless you happen to see it during a total solar eclipse -- using some heavy-duty eye protection, of course.

That layer is called the chromosphere, a layer of gases directly above the photosphere, which in turn is the bright visible surface of the sun that gives us all that warm, pretty sunshine during the day. The chromosphere comes from the Greek 'chroma-,' which means 'indicating color or pigment.' Thus, chromosphere means 'sphere of color.'

What Are Spicules?

When you look at the structure of the chromosphere, it looks pretty ragged. It almost looks like a field has been set alight with fire. This ragged appearance is caused by spicules, jets of gas in the chromosphere of the sun. These spicules shoot upwards at about 50,000 miles per hour for about five to fifteen minutes before falling back down, and there are a good hundred thousand of them in the chromosphere at any given moment.

Such spicules are likely caused, in part, by magnetic fields in the sun, and they rise up around the edges of supergranules, kind of like grass rises up around the edge of a big rock in a field of grass. Supergranules are areas in the sun's photosphere where currents of gas rise and fall by way of convection.

Naturally, you would think these jets of gas are hot gas but, relatively speaking, they are actually cooler gas jets coming from lower parts of the atmosphere. That is to say, in the chromosphere, things are opposite -- with cooler lower regions and hotter upper regions.

Other than the spicules, there isn't much else to the chromospheric gas structurally. It's pretty empty as it's only about 10^-8 as dense as the Earth's atmosphere. Consequently, the chromosphere is ordinarily difficult to see because there's so little material in it, resulting in transparency at most visible wavelengths.

To get around this, astronomers can use a filtergram, a photograph of the sun made using light of a specific region of the spectrum.

Why the Pinkish-Red Color?

Unlike the photosphere (which has an absorption line spectrum), the chromosphere has a spectrum composed mainly of emission lines.

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