ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

What Makes the Sky Red?

Updated on February 6, 2018
unvrso profile image

An avid camper and hiker as well as writer and astronomy lover, Jose Juan Gutierrez has always been inspired by the sky

Sunlight is Scattered in the Sky

The earth´s horizon may change tinge throughout the day. It may go from red to blue in a single day, depending on the time of day. In the morning, it may show reddish, orange and yellowish nuances and bluish at noon and then red orange and yellow matices before sunset. It is only when we take the time to carefully observe the Sun that we will notice the various tinges it acquires. Before sunlight penetrates the atmosphere and reaches the earth´s surface, it has to go through a great amount of dust particles and molecules in order to reach our eyes. The sun´s rays are scattered in the sky, with some wavelenghts being scattered more than others.

Higher frequency light, including violet and blue, which have a wavelength ranging between 380-450 and 450-475 nanometers respectively is scattered to a greater extent than shorter wavelengths, such as yellow, orange and red whose wavelengths are between 570-590, 590-620 and 620-750 nanometers respectively. The scattering of light in the atmosphere is proportional to the fourth power of light wavelength, therefore, the higher frequencies (blue, indigo and violet) become more scattered than the lower frequencies (yellow, orange and red).

It is this pronounced scattering of high frequency light that gives the sky its characteristic blue color. Although violet is more easily scattered when interacting with atmospheric particles, our eyes are more sensitive to perceive light with blue frequencies which becomes apparent when we witness the blue sky.

Red Sky

Red Sky
Red Sky | Source

The Sun at Noon

When the sun is high in the sky, it shines through the whole spectrum of visible light. Most of the wavelengths of the spectrum are able to reach the surface of the Earth, giving the Sun its bright color. Some wavelengths, such as blue and violet are deviated when colliding with the particles in the atmosphere, providing the noon sky its characteristic blue color. The lower frequencies, including the green and red longer wavelengths are able to pass through the atmosphere in an uninterrupted path. When the red and green wavelengths are combined, they produce a yellowish color, creating the characteristic yellow color of the Sun at mid-day.

The dispersion of the light spectrum in the sky is known as Rayleigh scattering. Through the Rayleigh scattering, portions of light of different wavelengths are scattered when they collide with the particles composing the atmosphere. The scattering of light in the atmosphere is proportional to the fourth power of wavelength. The visible light spectrum includes wavelengths in the ranges between 400-700 nanometers. Wavelengths in the ranges between 400-475 nanometers are more scattered than the wavelengths between 570-750 nanometers which are shorter.

Rayleigh scattering

Rayleigh scattering
Rayleigh scattering | Source


Sunrise | Source

Reddish Nuances of a Morning Sunrise

When the Sun raises early in the horizon, it appears in a faint reddish hue. The distance that light has to displace itself through the atmosphere is longer than at noon due to the fact that the Sun is lying at a different angle at sunrise than at noon and light has to go through a denser atmosphere.

Higher frequencies get dispersed the most, and this can be witnessed in the various bluish and violet nuances around the morning sunrise. the reddish color of the Sun at dawn intensifies because sunlight has to overcome a higher density of particles in the atmosphere. According to Rayleigh scattering, the higher frequency wavelengths (violet and blue) are most commonly scattered in the sky than the lower frequency wavelengths (yellow, orange and red).

As red is the lower frequency wavelength of the visible spectrum, it gets scattered at a reduced amount, allowing its frequencies to reach the eyes of an observer on Earth, giving that reddish color which is characteristic of a red dawn; however, as the Sun continues raising in the sky, it gradually acquires different tinges.

As the Sun approaches noon, it will gradually acquire distinctive colors. This is so because sunlight has to traverse shorter distances in the atmosphere as the Sun raises gradually at different angles in the sky. From a reddish hue at sunrise, it will turn orange and then yellow at noon, reflecting the various colors of the visible spectrum from the lowest frequency wavelength (red) to the higher frequency wavelengths (orange and yellow).

© 2012 Jose Juan Gutierrez


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)