--- title: Big Bang: Stephen Hawking Criticizes Big Bounce Theory description: Stephen Hawking and 32 fellow scientists responded to an article published in "Scientific American" about the origins of the universe canonical: https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/ author: Aric Jenkins article:opinion: false article:content_tier: free article:published_time: 2017-05-13T19:06:06.000Z article:modified_time: 2026-02-23T04:54:45.495Z article:section: Science og:title: Stephen Hawking and Fellow Scientists Dismiss 'Big Bounce' Theory in Letter og:description: The letter was sent in response to a 'Scientific American' article og:url: https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltf1818f94d58eb7a0/69889582ab6d77416c6a9e40/stephen-hawking-trump.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 3000 og:image:height: 1688 og:image:alt: New Space Exploration Initiative "Breakthrough Starshot" Announcement og:type: article twitter:card: summary_large_image twitter:title: Stephen Hawking and Fellow Scientists Dismiss 'Big Bounce' Theory in Letter twitter:description: The letter was sent in response to a 'Scientific American' article twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltf1818f94d58eb7a0/69889582ab6d77416c6a9e40/stephen-hawking-trump.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Stephen Hawking and Fellow Scientists Dismiss 'Big Bounce' Theory in Letter > Sponsored content. 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Future Proof is TIME's weekly climate and energy newsletter, written by senior correspondent Justin Worland. It connects the energy transition to the decisions reshaping business, technology, policy and markets. #### Where can I follow the energy transition as a business story? Future Proof covers climate and energy as an economic and business story rather than only an environmental one. It publishes every Friday and is free at time.com/newsletters. #### Who writes Future Proof? Justin Worland, a senior correspondent at TIME and an award-winning climate journalist, writes Future Proof. #### Is Future Proof free? Yes. Future Proof is free at time.com/newsletters. by [Aric Jenkins](https://time.com/author/aric-jenkins/) ## Aric Jenkins May 13, 2017 7:06 PM UTC  Cosmologist Stephen Hawking attends the New Space Exploration Initiative "Breakthrough Starshot" Announcement at One World Observatory on April 12, 2016 in New York City. Cosmologist Stephen Hawking attends the New Space Exploration Initiative "Breakthrough Starshot" Announcement at One World Observatory on April 12, 2016 in New York City. Gary Gershoff—WireImage/Getty Images by [Aric Jenkins](https://time.com/author/aric-jenkins/) ## Aric Jenkins May 13, 2017 7:06 PM UTC [Stephen Hawking](http://time.com/4767595/stephen-hawking-100-years-new-planet/) and 32 fellow scientists have written a critical [letter ](https://blogs.scientificamerican.com/observations/a-cosmic-controversy/)in response to an [article published in _Scientific American_](https://www.scientificamerican.com/article/cosmic-inflation-theory-faces-challenges/) that details an alternative theory on how the universe began. Hawking and his colleagues firmly believe in the widely-accepted theory of inflation, which describes how the universe rapidly expanded following the Big Bang. But three physicists, Anna Ijjas, Paul J. Steinhardt, Abraham Loeb, argued in the article that another theory, the “Big Bounce,” was more likely an explanation for the universe’s origins. Hawking and his peers did not entertain the idea. “By claiming that inflationary cosmology lies outside the scientific method, IS&L \[the authors of the earlier article\] are dismissing the research of not only all the authors of this letter but also that of a substantial contingent of the scientific community,” [they wrote to _Scientific American._](https://blogs.scientificamerican.com/observations/a-cosmic-controversy/) “Moreover, as the work of several major, international collaborations has made clear, inflation is not only testable, but it has been subjected to a significant number of tests and so far has passed every one,” the letter added. Ijjas, Steinhardt and Loeb were disappointed with the scientists’ response. “We firmly believe that in a healthy scientific community, respectful disagreement is possible and hence reject the suggestion that by pointing out problems, we are discarding the work of all of those who developed the theory of inflation and enabled precise measurements of the universe,” they responded. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/"},"headline":"Stephen Hawking and Fellow Scientists Dismiss 'Big Bounce' Theory in Letter","datePublished":"2017-05-13T19:06:06.000Z","dateModified":"2026-02-23T04:54:45.495Z","description":"Hawking and his colleagues weren't having it","url":"https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/","keywords":["Physics","onetime"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltf1818f94d58eb7a0/69889582ab6d77416c6a9e40/stephen-hawking-trump.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Aric Jenkins","jobTitle":null,"url":"https://time.com/author/aric-jenkins/"}],"articleSection":"Science","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltf1818f94d58eb7a0/69889582ab6d77416c6a9e40/stephen-hawking-trump.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"New Space Exploration Initiative \"Breakthrough Starshot\" Announcement","caption":"Cosmologist Stephen Hawking attends the New Space Exploration Initiative \"Breakthrough Starshot\" Announcement at One World Observatory on April 12, 2016 in New York City.","creditText":"Gary Gershoff—WireImage/Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/science/","name":"Science"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/physics/","name":"Physics"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/4778304/stephen-hawking-scientific-american-letter-big-bounce/","name":"Stephen Hawking and Fellow Scientists Dismiss 'Big Bounce' Theory in Letter"}}]}] ```