ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel
  • »
  • Education and Science»
  • Astronomy & Space Exploration

The Blood Moon of April

Updated on April 2, 2015
Click thumbnail to view full-size
Click thumbnail to view full-size

Why does the moon turn Red?



As we know the moon shines by reflecting sunlight. A total lunar eclipse occurs when the earth moves between the sun and moon. This effectively blocks much of the glow of the moon and produces a reddish glow earning it the moniker of a “Blood Moon.”
The principal of Rayleigh scattering explains why the moon turns red during the lunar eclipse. In fact, it is the same process which gives us colorful sunsets. Rayleigh scattering is named after Lord Rayleigh a British physicist.

John William Strutt, better known as Lord Rayleigh, the Third Baron Rayleigh developed a lengthy complicated equation explaining the scattering of solar radiation by the atmosphere. It is a difficult equation to explain the process, but the important thing take away is that the scattering is inversely proportional to the fourth power of the wavelength.

This means in layman's terms that the longest wavelengths are in the red/orange spectrum are scattered the least and the shortest wavelengths in the blue/violet range scatter the most. This is why the sky is blue and the sun takes on a reddish hue as sunrise and sunset.

As the sun’s radiation passes through the Earth’s atmosphere during a lunar eclipse, allowing red light to pass through and be reflected by the earth producing a blood moon. .


People who are avid eclipse watchers say that if you look closely at the very beginning and at the end may see a blue band on the moon's face this ring is caused by our ozone layer scattering the red spectrum light and allows some blue light through. Because of this, at the height of the eclipse when the moon turns red we are actually seeing every sunrise and sunset on earth

Click thumbnail to view full-size

How do we rate eclipses?


The Danjon Scale is how scientists measure appearance and brightness of a lunar eclipse. The Danjon Scale was created by Andre-Louise Danjon a French astronomer in 1921 it was believed the brightness of a lunar eclipse was related to the solar cycle.

The Danjon Scale brightness provides a useful tool for measuring the appearance and luminosity of the moon during a lunar eclipse. An eclipse's rating on the Danjon Scale is traditionally denoted by the letter L and measures the brightness of the eclipse on the 5 point scale below.


Determination of the value of L for an eclipse is best done near mid-totality with the naked eye. The scale is subjective, and different observers may determine different values. In addition, different parts of the Moon may have different L values, depending on their distance from the center of the Earth's umbra.

Many factors can affect the appearance of the Moon during a lunar eclipse. The Moon's path through the Earth's umbr is important, but so too are the current conditions of the earth's atmosphere. While the Earth's shadow blocks any direct light from striking the Moon during a lunar eclipse, some light is refracted through the Earth's atmosphere giving a Moon a red hue.

The amount of light refracted affects the brightness of the moon at mid-eclipse, and this depends on several factors. For instance volcanic eruptions are one of the most significant. These eruptions fill the air with ash resulting in deep dark red lunar eclipses. one of the most significant of this effect. The eruption at Mount Pinatubo in early 1992 caused the lunar eclipse in December of that year to be rated a 0 on the on the Danjon Scale..



Click thumbnail to view full-size

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com 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: "https://hubpages.com/privacy-policy#gdpr"

    Show Details
    Necessary
    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 googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    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)
    Marketing
    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.
    Statistics
    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)