What Color is the Sun?

What Color is the Sun?

What is the color of the Sun? The answer depends upon the viewer! Some might say yellow. Others might say red or orange. An alien might say white from their distant vantage point. Not many would say green. Is green an acceptable answer? Let’s find out.

Dr. MMM of AstroPicionary has taught astronomy to 10,000+ students over 15+ years at a USA Carnegie Level R1 University. Dr. MMM continues to teach astronomy and physics. She authors textbooks in astronomy that are in use worldwide. Here, Dr. MMM discusses the color of the Sun, which sounds like an easy topic but could have many different answers.

Common Shades of the Sun

Yellow, orange, and red are common colors viewers select for the Sun. Let’s look at images of the Sun in these three common colors.

Sun Color – Yellow

The Sun appears yellow as the image below shows. To see a yellow Sun, view well above the horizon of Earth. To safely see the Sun, use a camera on a tripod to take an image like this one.

Image of yellow Sun courtesy of Bulat yang indah under CC BY-SA 4.0

The above image is over a rice paddy in Karawang, West Java, Indonesia and the Sun is well above the horizon.

As the Sun is well above the horizon for many hours per day, many viewing might choose yellow as the color of the Sun. However, some may choose orange or red.

Sunlight streaming into a telescope or a camera near sunset or sunrise appears red (top sketch of Sun in diagram shown below) because sunlight passes through more of Earth’s lower, denser layers of Earth’s atmosphere than when the Sun is overhead. When Sun is overhead, near noon, the Sun appears yellow (bottom sketch of Sun in diagram shown below) because sunlight passes through less of Earth’s atmosphere than at sunset or sunrise. The more atmosphere sunlight passes through, the more blue light is scattered, hence the Sun is more red at sunrise and sunset.

Diagram of sunlight angles into telescopes placed around Earth, courtesy of Peter Halasz under CC BY-SA 2.5, modified by Dr. M. M. Montgomery and used with permission (telescopes added, ray colors changed, Sun colors change)

Sun Color – Orange

The image below shows an orange Sun. The Sun is lower in the sky relative to the image of the yellow Sun in the image above and in the diagram above. The closer the Sun is to the horizon, the more orange the Sun appears to an Earthling.

Image of orange color Sun courtesy of User:Soph556 under CC BY-SA 3.0

The above image is from Australia during summer 2005. The sky appears mostly orange.

Sun Color – Red

The Sun appears more red when on the horizon like that shown in the image below. The sky all around also appears red. This image shows a flock of red-winged blackbirds flying near sunset.

Image of sunset courtesy of Jerry Segraves under Public Domain

Uncommon Shades of the Sun

White, pink, and green are less common colors chosen for the Sun. Let’s look at these colors associated with the Sun.

Sun Color – White

Some might choose white for the Sun’s color. Below shows an image of a white Sun. This image is by one of the Expedition 36 crew on the International Space Station (ISS). The Earth is in the bottom half of the image and part of the ISS is at the top half. At the time this image, which is May 2013, the ISS is above southwest Minnesota, USA.

Image of white Sun courtesy of NASA under Public Domain

Sun Color – Pink

Some might choose pink as the Sun’s color. The two images below show a pink Sun. The image on left is taken in the early hours with minimal brightness in 2015 in Karnataka, a state on the southwestern coast of India. The image on right is taken at Vagator Beach in north Goa, which also is a state on the southwestern coast of India.

Image (left) courtesy of Pramodv1993 under CC BY-SA 4.0 and image (right) courtesy of Swapnilshirali under CC BY-SA 4.0

A Green Sun?

As for the color green, a green flash of the Sun for a second or two at sunset comes to mind. The image below captures this green flash as seen from Cerro Paranal, a tall mountain in Chile, South America. This image shows a more rare double green flash, a lime one immediately above the Sun and a Kelly green one above that.

Image of green flash at sunset, courtesy of ESO/G. Lombardi under CC BY 3.0

Seeing a green flash at sunset or sunrise is rare. To see a flash, three conditions must be met:

  • The day has to be clear.
  • Earth’s atmosphere must be calm.
  • Your vantage must be unobstructed.

Viewing from a beach or on water is ideal. The above image is taken from a mountain, which is also a good choice.

Notice the green flash appears just above the Sun. The diagram in Sun Color – Yellow subsection above shows long wavelength red light passing through Earth’s lower atmosphere, which is a denser atmospheric layer. This denser layer bends shorter wavelength green light, leaving red light nearly unbent. As green light from the Sun bends when passing through Earths more dense lower atmosphere at sunrise and sunset, green light from the Sun appears about the red Sun. Nonetheless, you are looking at green light from the Sun during this flash. As the green light does not appear on the Sun during the flash, our human eyes would not say that the Sun is green; our eyes would say the flash appears above the Sun.

A source to the two different shades of green in the image is sunlight streaming through two alternating layers in Earth’s atmosphere. One layer contains warm air, and one layer contains cold air. Notice that the Sun and the sky do not appear green.

Any Green Stars?

Green stars are rare in nature due to a narrow band that green has in the electromagnetic spectrum. The video below explains the electromagnetic spectrum and is from the YouTube channel AstroPictionary.

As seen in this image of the video above, green has a narrow wavelength band compared to red and blue. Stars appear red, orange, yellow, white, or blue to our Earthling eyes.

If stars emit more red than blue, then stars appear red. A star that emits more red than green, it will appear orange. If a star emits more red than green and more green than blue, then it will appear yellow. If stars emit more blue than red, then stars appear more blue or violet.

The animation below shows a color shade in the circle that our eyes might see based on the amount of red, green, or blue a star emits. Although the animation only shows red, green, and blue, human eyes easily differentiate these colors. The animation shows that green is not easily seen: When a star emits equal amounts of red, green, and blue, the star appears white. White is a blend of colors.

Animation courtesy of Jacopo Bertolotti under CC0 1.0

As the left animation shows, stars usually emit over a wide wavelength spectrum. As green is in the middle of the rainbow of colors, not likely will a star emit only green wavelengths. Close to a green color is teal; however, teal is still a blend of more blue than green colors.

One star that emits more chartreuse than any other color of the rainbow is the Sun! The graph below shows the Sun’s true spectrum (jagged white line) and an ideal blackbody spectrum (yellow line) that has a peak in the color green. Although the Sun’s emission color peaks in green, the Sun’s emission is a blend of the rainbow of colors.

Graph courtesy of Danmichaelo under Public Domain

Although the Sun cannot be truly categorized as a green star, the Sun does have a peak color of green.

Bottom Line

The color of the Sun can be red, orange, yellow, pink, and white, depending on who or what is viewing, the viewing angle, and whether viewing from Earth’s surface or from space. Although the Sun has a peak color of green in its spectrum and emits a green flash of light above the solar disk that Earthlings can see under ideal conditions, astronomers do not consider the Sun a green star.

Green stars are typically not seen in telescope V band images: If a star emits green light, then that star is nearly always emitting another color(s) of light simultaneously, the net of which is a blend. A blend of red R, orange O, yellow Y, green G, blue B, indigo I, and violet V (ROYGBIV) colors would render a white star color.

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About the author

Michele M. Montgomery earned a B.S. Degree in Nuclear/Mechanical Engineering from the Pennsylvania State University, an M.S. Degree in Physics from The University of Alabama with a concentration in Solar Physics, and a Ph.D Degree in Physics from Florida Institute of Technology with a concentration in close binary star systems. She joined the faculty at The University of Central Florida Physics Department in 2004 where she regularly taught astronomy, astrophysics, and cosmology. In 2006, she noticed that a large, urban college nearby to UCF did not teach astronomy at one of their largest campuses. She began teaching astronomy at this East Campus of Valencia College, a college that has more than 60,000 students; she still teaches four courses of astronomy each fall, spring, and summer semesters. The astronomy program atValencia College East has grown significantly with several more faculty added who teach astronomy.

By 2019, Dr. Montgomery has taught astronomy to more than 10,000 college and university students, both online and face-to-face. Many of her students have gone on to take her astrobiology, astrophysics, and space physics courses. 

By 2016, Dr. Montgomery had co-authored several astronomy texts and quiz/exam banks. Her work appears in several domestic and international astronomy text books (e.g., Horizons by Cengage, Universe by Cengage, Foundations of Astronomy by Cengage) that are used both at the higher education as well as at the high school levels. Starting in Fall 2019, Dr. Montgomery switched gears to authoring digital textbooks and research full time, while still teaching 12 courses of astronomy and up to eight conceptual, algebra, and/or calculus-based physics courses each year. Her research interests are numerical simulations using Smoothed Particle Hydrodynamics of close binary star systems. She also regularly is granted telescope time on the NASA's Kepler space telescope for observing eclipsing binary star systems. She has also observed using Gemini South, Keck, and Kitt Peak ground-based telescopes. Her major teaching areas are Astronomy, Astrobiology, Astrophysics, Cosmology, Space Weather/Space Physics.