What Is Obler's Paradox?

Updated on January 8, 2018
1701TheOriginal profile image

Leonard Kelley holds a bachelor's in physics with a minor in mathematics. He loves the academic world and strives to constantly explore it.


Let’s jump right into it. If there are so many stars in the night sky, why is it black? Yes, the sun does go down and removes a huge light source but what about all the stars, galaxies, and nebula out there? Even if the Universe were infinite in size, we should see something everywhere. And yet…darkness reigns with just a few pinpoints of light to break it up. But some might bring up some possible answers to this conundrum, which should be examined to see their veracity. Some point out that stars which are too faint to see at the distance they are located at do exist, but when they initially formed the Universe was a lot smaller and so they have distributed out fairly well as the Universe has expanded, creating no bias in brightness. Others have suggested that maybe stars are not evenly distributed in the Universe but follow some bias, or that there are simply not enough of them out there. And this is almost certainly a true statement, but when you look at a larger and larger scope of the universe everything seems to average out rather well, again because of our expanding Universe. And the number of stars needed to light up the Universe isn’t that hard a figure to get to, as it turns out. So…why is the sky dark? (Al 43-4, Chase, Nave)

The paradox was named by Herrmann Bondi in 1952 after hearing about Heinrich Wilhelm Obler’s efforts in the 1800’s to resolve it, but the paradox was around a long time before either people. We have to go all the way to 1576 when Thomas Digges modifies the Copernican system of the Universe. In his new addition of A Prognostication Everlasting, he essentially keeps the Copernican system untouched expect for one detail. Stars are not tiny holes in some outer shell of the Universe but are actually objects that are dispersed in a space that in infinitely large in size. Quite the statement from someone without proof in those days, but Digges claimed that the idea arose from Tycho Brahe’s supernova of 1572. That event displayed no parallax of motion, indicating that it was far away. But the heavens never changed according to the contemporary views of the time, but since this was now in question, why couldn’t other parts of the world view be changed also? Digges felt that with enough stars far away, the darkness in the sky could be explained and the system would be intact (Al 45-8).

Years later, Jean-Phillippe de Cheseaux shows that this cannot be true using geometry. Those outer stars have the same brightness component as the inner ones because of the volume of space they occupied together, acting like a big source of light even at such a distance. Obler in 1823 felt that interstellar dust and gas could obscure a lot of light from distant stars. As it turns out, the Universe has been around so long that the dust and gas has heated up via collisions and so they actually emit the same light as those distant stars they obscure, so no dice there (Al 50, Chase).

No, the solution lies in the expanding Universe. You see, light can only go so fast, and if the space it move through expands fast enough then it will take a long time for the light to reach you, especially when expanding faster than c. And even if the Universe wasn’t expanding currently, you still would have a dark sky at night because of inflation in the early Universe driving space apart faster than c. It didn’t last long but it did forever cause portions of space to be forever screened out. And because of a finite Universe, only so much has happened in a span of time. There is no way enough time has passed for stars to get to any of the configurations needed for a bright night sky. So, sorry everyone. The mechanics of the world are still maintained, and now you can look up at the night sky and realize you are witnessing an amazing moment in science (AL 58-9, NASA, Nave).

The sky as it would seem it should be...
The sky as it would seem it should be... | Source

Works Cited

Al-Khalili, Jim. Paradox: The Nine Greatest Enigmas in Physics. Broadway Paperbacks, New York, 2012: 43-8, 50 PAGES. Print.

Chase, Scott I. “Olber’s Paradox.” Math.ucr.edu. UCR, 2004. Web. 19 Sept. 2017.

NASA. “Why is the Sky Dark at Night?” spaceplace.nasa.gov. NASA. Web. 19 Sept. 2017.

Nave, R. “Olber’s Paradox: Why is the Sky Dark at Night?” hyperphysics.phy-astr.gsu.edu. Georgia State Univeristy,2000. Web. 19 Sept. 2017.

© 2018 Leonard Kelley


    0 of 8192 characters used
    Post Comment
    • Guckenberger profile image

      Alexander James Guckenberger 

      2 years ago from Maryland, United States of America

      Of course! I loved learning what this is!!!

    • 1701TheOriginal profile imageAUTHOR

      Leonard Kelley 

      2 years ago


    • Guckenberger profile image

      Alexander James Guckenberger 

      2 years ago from Maryland, United States of America

      very nice :)


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, owlcation.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://maven.io/company/pages/privacy

    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 googleapis.com or gstatic.com 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)