--- title: "Meaning & Key Takeaway of: The universe appears to be a system of…" description: "\"“The universe appears to be a system of very low density wherever we look. This is no accident. The expansion of the Universe weds its size and age to ..." image: "https://sms4smile.com/quotes/i/2c2/john-d-barrow-4552_astronomy_the-universe-appears-to-be-a-system-of-v_557095.jpg" --- # The universe appears to be a system of very low density… ![“The universe appears to be a system of very low density wherever we look. This is no accident. The expansion of the Universe weds its size and age to the gravitational pull of the material that it contains. In order that a universe expands for long enough to allow the building blocks of life to…” quote by John D. Barrow](https://sms4smile.com/quotes/i/2c2/john-d-barrow-4552_astronomy_the-universe-appears-to-be-a-system-of-v_557095.jpg) [Download](https://sms4smile.com/quotes/i/2c2/john-d-barrow-4552_astronomy_the-universe-appears-to-be-a-system-of-v_557095.jpg) [Open image](https://sms4smile.com/quotes/i/2c2/john-d-barrow-4552_astronomy_the-universe-appears-to-be-a-system-of-v_557095.jpg) > ““The universe appears to be a system of very low density wherever we look. This is no accident. The expansion of the Universe weds its size and age to the gravitational pull of the material that it contains. In order that a universe expands for long enough to allow the building blocks of life to form in the interiors of stars, by a sequence of nuclear reactions, it must be billions of years old. This means that it must be billions of light years in extent and possess a very small average density of matter and a very low temperature. The low temperature and energy of its material ensures that the sky is dark at night. Turn off our local Sun and there is just too little light around in the Universe to brighten the sky. The night is dark, interspersed only by pinpricks of starlight. Universes that contain life must be big and old, dark and cold. If our Universe was less of a vacuum it could not be an abode for living complexity.”” [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) ## About This Quote This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation. The universe’s low density, great age, and cold darkness are necessary conditions for life to develop within stars. **In simple terms:** Life needs a vast, old, dark, and cold universe. Key Takeaway Recognize how cosmic conditions shape possibility. Themes cosmology anthropic principle life universe temperature density Mood thoughtful reflective scientific Type philosophical scientific educational When to use this quote - astro‑biology research - cosmic background studies - philosophical debates on existence Key Concepts entropy fine‑tuning stellar nucleosynthesis Questions to Reflect On - What cosmic parameters most limit life? - How does darkness enable star formation? A Different Perspective If the universe were denser, complex life could not arise. ★ ★ ★ ★ ★ No ratings yet [Astronomy](https://sms4smile.com/quotes/about/astronomy/) [Building blocks](https://sms4smile.com/quotes/about/building-blocks/) ## Related quotes > [Ah, but I am more perceptive than most of the universe. Especially the parts of the universe that are vacuum.](https://sms4smile.com/quotes/james-alan-gardner/ah-but-i-am-more-perceptive-than-most-of-the-universe-especially-the/) [James Alan Gardner](https://sms4smile.com/quotes/author/james-alan-gardner/) > [“The success of discovering a thermodynamic principle associated with the gravitational field of a black hole has led to a speculation that there might…](https://sms4smile.com/quotes/john-d-barrow/the-success-of-discovering-a-thermodynamic-principle-associated-with/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [Or in other words, why does disorder increase in the same direction of time as that in which the universe expands?](https://sms4smile.com/quotes/stephen-hawking/or-in-other-words-why-does-disorder-increase-in-the-same-direction-of/) [Stephen Hawking](https://sms4smile.com/quotes/author/stephen-hawking/) > [“A King and Queen cannot support a crown with eyes looking down. Their universe expands as far as you can see.”](https://sms4smile.com/quotes/t-f-hodge/a-king-and-queen-cannot-support-a-crown-with-eyes-looking-down-their/) [T.F. Hodge](https://sms4smile.com/quotes/author/t-f-hodge/) > [“The space that is added as the universe expands has the same properties-curvature, energy density-as the parent space.”](https://sms4smile.com/quotes/henning-genz/the-space-that-is-added-as-the-universe-expands-has-the-same/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“the universe expands forever in every direction for all of time, taking on the shape of a saddle, in which initially parallel lines diverge.”](https://sms4smile.com/quotes/neil-degrasse-tyson/the-universe-expands-forever-in-every-direction-for-all-of-time/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) > [Eventually, when the universe expands enough, all that will be left is the dark energy.](https://sms4smile.com/quotes/leonard-susskind/eventually-when-the-universe-expands-enough-all-that-will-be-left-is/) [Leonard Susskind](https://sms4smile.com/quotes/author/leonard-susskind/) > [“you smile and the universe expands.”](https://sms4smile.com/quotes/gwen-calvo/you-smile-and-the-universe-expands/) [Gwen Calvo](https://sms4smile.com/quotes/author/gwen-calvo/) > [Every day you play with the light of the universe.](https://sms4smile.com/quotes/pablo-neruda/every-day-you-play-with-the-light-of-the-universe/) [Pablo Neruda](https://sms4smile.com/quotes/author/pablo-neruda/) > [“Because," Leonard said, "light overcomes darkness. 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Barrow > [“One of Nature's deep secrets is the fact that the outcomes of the laws of Nature do not have to possess the same symmetries…](https://sms4smile.com/quotes/john-d-barrow/one-of-nature-s-deep-secrets-is-the-fact-that-the-outcomes-of-the/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [“The effect of the 'time becomes space' proposal is that there is no definite moment or point of creation. In more conventional quantum mechanical…](https://sms4smile.com/quotes/john-d-barrow/the-effect-of-the-time-becomes-space-proposal-is-that-there-is-no/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [“Humans are distinguished further by the highly effective way in which they have pooled the individual intelligence of single individuals to produce a collective…](https://sms4smile.com/quotes/john-d-barrow/humans-are-distinguished-further-by-the-highly-effective-way-in-which/) [John D. 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Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [“Life as we know, and partially understand it, is a classical example of what can occur when a sufficient level of complexity is attained.…](https://sms4smile.com/quotes/john-d-barrow/life-as-we-know-and-partially-understand-it-is-a-classical-example-of/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [“There is no formula that can deliver all truth, all harmony, all simplicity. No Theory of Everything can ever provide total insight. For, to…](https://sms4smile.com/quotes/john-d-barrow/there-is-no-formula-that-can-deliver-all-truth-all-harmony-all/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) > [History is full of people who thought they were right -- absolutely right, completely right, without a shadow of a doubt. And because history…](https://sms4smile.com/quotes/john-d-barrow/history-is-full-of-people-who-thought-they-were-right-absolutely/) [John D. Barrow](https://sms4smile.com/quotes/author/john-d-barrow/) [Explore all 109 John D. Barrow quotes ](https://sms4smile.com/quotes/author/john-d-barrow/) ## More Astronomy quotes > [I have inside me the winds, the deserts, the oceans, the stars, and everything created in the universe. We were all made by the…](https://sms4smile.com/quotes/paulo-coelho/i-have-inside-me-the-winds-the-deserts-the-oceans-the-stars-and/) [Paulo Coelho](https://sms4smile.com/quotes/author/paulo-coelho/) > [Mankind have been slow to believe that order reigns in the universe-that the world is a cosmos and a chaos.](https://sms4smile.com/quotes/james-a-garfield/mankind-have-been-slow-to-believe-that-order-reigns-in-the-universe/) [James A. Garfield](https://sms4smile.com/quotes/author/james-a-garfield/) > [Wen daylight turns to a darkened hue, D lovely stars hinting at u, ur heart beat tells u something true, That some 1 badly…](https://sms4smile.com/quotes/butterfly-kisses/wen-daylight-turns-to-a-darkened-hue-d-lovely-stars-hinting-at-u-ur/) Butterfly\_Kisses > [Home is behind, the world ahead, And there are many paths to tread Through shadows to the edge of night, Until the stars are…](https://sms4smile.com/quotes/anonymous/home-is-behind-the-world-ahead-and-there-are-many-paths-to-tread/) [Anonymous](https://sms4smile.com/quotes/author/anonymous/) > [In the movie, the stars above the ship bear no correspondence to any constellations in a real sky. Worse yet, while the heroine bobs...…](https://sms4smile.com/quotes/neil-degrasse-tyson/in-the-movie-the-stars-above-the-ship-bear-no-correspondence-to-any/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) > [Astronomers have built telescopes which can show myriads of stars unseen before; but when a man looks through a tear in his own eye,…](https://sms4smile.com/quotes/henry-ward-beecher/astronomers-have-built-telescopes-which-can-show-myriads-of-stars/) [Henry Ward Beecher](https://sms4smile.com/quotes/author/henry-ward-beecher/) > [From the grasses in the field to the stars in the sky, each one is doing just that; and there is such profound peace…](https://sms4smile.com/quotes/rabindranath-tagore/from-the-grasses-in-the-field-to-the-stars-in-the-sky-each-one-is/) [Rabindranath Tagore](https://sms4smile.com/quotes/author/rabindranath-tagore/) > [“Sentinels of trees breathe life into bodies of earthly flesh As their mighty arms reach to the stars we join in their quest for…](https://sms4smile.com/quotes/ramon-ravenswood/sentinels-of-trees-breathe-life-into-bodies-of-earthly-flesh-as-their/) [Ramon Ravenswood](https://sms4smile.com/quotes/author/ramon-ravenswood/) > [“If there are no stars on the sky, you must try to be happy with the shining streetlights!”](https://sms4smile.com/quotes/mehmet-murat-ildan/if-there-are-no-stars-on-the-sky-you-must-try-to-be-happy-with-the/) [Mehmet Murat ildan](https://sms4smile.com/quotes/author/mehmet-murat-ildan/) > [Twinking tears in a sea of black. 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The cosmic…](https://sms4smile.com/quotes/marianne-williamson/the-reason-so-many-of-us-are-obsessed-with-becoming-stars-is-because/) [Marianne Williamson](https://sms4smile.com/quotes/author/marianne-williamson/) [Browse all 6,190 Astronomy quotes ](https://sms4smile.com/quotes/about/astronomy/) ```json { "@context": "https://schema.org", "@graph": [ { "@type": "Quotation", "text": "“The universe appears to be a system of very low density wherever we look. This is no accident. The expansion of the Universe weds its size and age to the gravitational pull of the material that it contains. In order that a universe expands for long enough to allow the building blocks of life to form in the interiors of stars, by a sequence of nuclear reactions, it must be billions of years old. This means that it must be billions of light years in extent and possess a very small average density of matter and a very low temperature. The low temperature and energy of its material ensures that the sky is dark at night. Turn off our local Sun and there is just too little light around in the Universe to brighten the sky. The night is dark, interspersed only by pinpricks of starlight. Universes that contain life must be big and old, dark and cold. If our Universe was less of a vacuum it could not be an abode for living complexity.”", "creator": { "@type": "Person", "name": "John D. 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