ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

All About Solar and Lunar Eclipses

Updated on September 27, 2012
Solar and Lunar eclipses may only appear  "once in a blue moon."
Solar and Lunar eclipses may only appear "once in a blue moon." | Source
This Solar eclipse is an example of an annular eclipse.
This Solar eclipse is an example of an annular eclipse. | Source
For a lunar eclipse the Earth comes between the Sun and Moon, casting its shadow onto the Moon.
For a lunar eclipse the Earth comes between the Sun and Moon, casting its shadow onto the Moon. | Source

By Joan Whetzel

Every year, people somewhere in the world, have the opportunity to witness a solar or lunar eclipse. They may be partial, full, or annular eclipses, depending on the viewer's location at the time of the eclipse's occurrence. Any way you look at it, viewing an eclipse is a cool experience, especially once you understand what's happening.

What Are Eclipses?

An eclipse occurs when one celestial body completely obscures another. The term eclipse can also be defined as the period of time during which such an obstruction occurs. In the case of a solar eclipse, our view of the Sun, from the Earth's surface, is blocked. It also cuts off the Sun's light and warmth from the Earth, at least until the eclipse is over. In the case of a lunar eclipse, the Sun's light is blocked from hitting the Moon's surface, making it appear that the Moon has gone quite dim, at least from our point of view here on Earth.

Solar Eclipses

A solar eclipse occurs when the Moon passes between the Earth and the Sun. The Moon blocks the Sun's light and casts two shadows on the Earth's surface - the umbra and the penumbra. The umbra (the dark center of the Moon's shadow) grows smaller as it reaches the Earth's surface. The area of the Earth's surface covered by the umbra is the only area where a total solar eclipse is visible. The penumbra grows larger as gets closer to the Earth's surface.

Lunar Eclipses

A lunar eclipse occurs when the Earth comes between the Sun and the Moon, preventing the Sun's light from hitting the Moon's surface. In other word's the Moon grows quite dim because the it is in the Earth's shadow. This only happens when the Moon is full. Lunar eclipses occur at least twice a year either as a partial or a full eclipse. The lunar eclipse has an umbra and penumbra. The umbra has no direct solar radiation hitting the Moon's surface, which means the center of the Moon's disk will be the darkest. The penumbra allows a little light to hit the Moon's surface around the edges, leaving a ring around the outside that is a bit brighter than the center of the Moon.

Partial Eclipses

Partial lunar and solar eclipses appear as though only a portion of the Moon or Sun are being blocked from the viewpoint of the people witnessing the eclipse. Partial solar and lunar eclipses occur when:

· our vantage point puts us in the penumbra shadow during a solar eclipse.

· when our latitude is far enough north or south of the eclipse's path to change the angle of the eclipse and put our viewpoint out of the path of total obscuration.

· when the Sun, Moon, and Earth are lined up such that the shadow only crosses a portion of the Sun or Moon.

Full Eclipses

An eclipse is considered a total or full eclipse only when:

· Solar: the center of the Moon's shadow strikes the Earth and the Moon completely obscures our observation of the Sun.

· Lunar: the Moon passes completely into the Earth's shadow.

The path of a total solar eclipse covers a narrow strip only about 150 km (492,126 feet or 93 miles) wide. For a total solar eclipse to occur, there must a new Moon present and the Moon must be in the correct position, where it is placed directly between the Earth and the Sun. For a total lunar eclipse to occur, there must be a full Moon present and the Earth must be positioned so that it is lined up directly between the Sun and the Moon.

The reason that the Moon appears to totally eclipse the Sun, when it is obviously smaller than the

Sun, has to do with the size of the Moon and the Sun as well as the distances between the Sun and the Earth and between the Moon and the Earth. The Sun's diameter (864,000 miles or 1,390,473.2 km) is 400 times larger than the moon's diameter (2,160 miles or 3,476.1831km). However, the Moon is approximately 400 times closer to the Earth than the Sun. This distance to size ration creates sort of a forced perspective (similar to the forced perspective used to film the Lord of the Rings movies) that makes the Moon appear to be big enough to totally obscure the Sun.

This ratio, though, does vary a little since the earth has an elliptical orbit. Since the Earth has an elliptical orbit, the Moon may appear smaller (too small to block the sun) when in front of the Sun, creating an annular eclipse, or it may appear larger in comparison to the sun creating the full eclipse. So when the earth's orbit brings it closer to the sun, and a solar eclipse occurs, then it will be a total eclipse.

Annular Eclipses

Annular eclipses are, in essence, a total eclipse - with a twist. During an annular eclipse, either a slight ring of the Sun's light will appear around the MOON (solar eclipse) or a small ring will appear of the Moon will not appear in shadow (lunar eclipse).

Here's where the Earth's elliptical orbit comes in. Annular eclipses occur when the Earth is farthest away from the Sun. So, in the case of solar eclipses, the Moon will not be quite large enough to completely hide the Sun, but will appear slightly smaller, which allows the "ring of fire" around the outside of the Moon. In the case of lunar eclipses, the Earth will not completely block the Sun's light, so the center of the Moon will go dark, with a very small ring of brightness appearing around the perimeter.

Eclipse Experiment: On any night when the Moon is full, go outside and look up. Close one eye, then extend your arm toward the Moon, holding your thumb up, placing your thumb between you and the Moon. Does it obscure the Moon completely. Slowly move your thumb closer to your eyes, and notice how your thumb appears to grow large enough to obscure your view of the moon completely. This will give you an idea of the difference between an annular eclipse and a total eclipse.

Resources

American Heritage Dictionary. Eclipse.

http://education.yahoo.com/reference/dictionary/entry/eclipse

Starchild Forum. What Is an Eclipse?

http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question6.html

Space.com. What Is a Solar Eclipse

http://www.space.com/15584-solar-eclipses.html

NASA. Lunar Eclipses - Past and Future.

http://eclipse.gsfc.nasa.gov/lunar.html

New World Encyclopedia. Lunar Eclipse.

http://www.newworldencyclopedia.org/entry/Lunar_eclipse

Eclipses

Solar Eclipse 01-26-2009

Solar Eclipse

Lunar Eclipse 03-03-07

Lunar Research Orbiter - Lunar Eclipse

Comments

    0 of 8192 characters used
    Post Comment

    • darknezz111 profile image

      Daniel Durand 

      5 years ago from Southern Idaho

      Very informative. I hope to see more!

    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)