--- title: "Meaning & Key Takeaway of: Let's return to Archytas's staff and to…" description: "\"“Let's return to Archytas's staff and to the expanding Universe. A javelin that is thrown straight upward will drop back down a long time before we can..." image: "https://sms4smile.com/quotes/i/b27/henning-genz-4557_big-bang_let-s-return-to-archytas-s-staff-and-to_1074907.jpg" --- # Let's return to Archytas's staff and to the expanding… ![“Let's return to Archytas's staff and to the expanding Universe. A javelin that is thrown straight upward will drop back down a long time before we can sensibly ask the question about the edge of the universe. The javelin cannot escape the gravity of Earth. A spacecraft that runs out of propellant…” quote by Henning Genz](https://sms4smile.com/quotes/i/b27/henning-genz-4557_big-bang_let-s-return-to-archytas-s-staff-and-to_1074907.jpg) [Download](https://sms4smile.com/quotes/i/b27/henning-genz-4557_big-bang_let-s-return-to-archytas-s-staff-and-to_1074907.jpg) [Open image](https://sms4smile.com/quotes/i/b27/henning-genz-4557_big-bang_let-s-return-to-archytas-s-staff-and-to_1074907.jpg) > ““Let's return to Archytas's staff and to the expanding Universe. A javelin that is thrown straight upward will drop back down a long time before we can sensibly ask the question about the edge of the universe. The javelin cannot escape the gravity of Earth. A spacecraft that runs out of propellant only after it reaches the velocity that permits escape from the gravitational pull of our solar system will continue on its path, but it will remain inside our galaxy. The Milky Way's gravitational field holds onto it. Proceeding like this, we pass, from a practical problem to a fundamental question. Can there be objects that may escape our group of galaxies and that will ultimately leave our universe altogether? The answer must be no. The universe, after all, keeps expanding. Light that reaches us today was emitted shortly after the birth of the universe; its headwaters are moving away from us with a velocity close to that of light. There is no light older than what originated at the time of the Big Bang. Since no information travels at a speed greater than that of light, the observable universe is contained within the surface of a sphere with a radius defined by the distance traveled by light that was emitted at the time of the Big Bang.”” [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) ## About This Quote This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation. The speaker explains that cosmic expansion and light speed limit confine observable universe, making escape from the galaxy or universe impossible. **In simple terms:** Space expansion and light speed keep us within a cosmic horizon. Key Takeaway Accept our cosmic limits and focus on local impact. Themes cosmology physics limits expansion light speed Mood wonder humble inquisitive Type educational inspirational When to use this quote - astronomy education - public lecture - science communication - philosophical reflection Key Concepts observable universe light horizon galactic escape cosmic expansion Questions to Reflect On - What does our cosmic horizon mean for humanity's future? - How can we responsibly explore within these limits? A Different Perspective The analogy may oversimplify complex astrophysical concepts. ★ ★ ★ ★ ★ No ratings yet [Big bang](https://sms4smile.com/quotes/about/big-bang/) [Escape Gravitational](https://sms4smile.com/quotes/about/escape-gravitational-681875/) [Escape Gravity](https://sms4smile.com/quotes/about/escape-gravity-1634940/) [Expanding universe](https://sms4smile.com/quotes/about/expanding-universe/) [Long time](https://sms4smile.com/quotes/about/long-time/) [Solar system](https://sms4smile.com/quotes/about/solar-system/) [Time](https://sms4smile.com/quotes/about/time/) [Universe Javelin](https://sms4smile.com/quotes/about/universe-javelin-2696397/) [Universe Keeps](https://sms4smile.com/quotes/about/universe-keeps-2636899/) ## Related quotes > [“In order to show that not even light can escape from the gravitational pull of a black hole, we have to hone the argument…](https://sms4smile.com/quotes/henning-genz/in-order-to-show-that-not-even-light-can-escape-from-the/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [One can imagine that God created the universe at literally any time in the past. 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The effect of lambda grows steadily with respect to the familiar Newtonian…](https://sms4smile.com/quotes/john-d-barrow/when-one-looks-at-the-numbers-the-situation-becomes-even-more/) [John D. 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We…](https://sms4smile.com/quotes/henning-genz/the-higgs-field-originated-as-the-universe-cooled-down-after-the-big/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“The same energy density that we reach today in electron-positron collisions pervaded the entire universe one ten-billionth of a second after the Big Bang.…](https://sms4smile.com/quotes/henning-genz/the-same-energy-density-that-we-reach-today-in-electron-positron/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“The energy that was hidden in the false vacuum is liberated in the course of this phase transition of the universe into the real…](https://sms4smile.com/quotes/henning-genz/the-energy-that-was-hidden-in-the-false-vacuum-is-liberated-in-the/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“At the end of inflation, just as after the hot Big Bang, the universe is hot. It is, we might say, self-created by dint…](https://sms4smile.com/quotes/henning-genz/at-the-end-of-inflation-just-as-after-the-hot-big-bang-the-universe/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“To gain any intuitive understanding of the breakdown of this ultimate symmetry through vacuum effects at the critical 10^-44 seconds after the Big Bang,…](https://sms4smile.com/quotes/henning-genz/to-gain-any-intuitive-understanding-of-the-breakdown-of-this-ultimate/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) ## More by Henning Genz > [“Recall our discussion of the pendulum. Its position at a given instant does not fix its subsequent behavior. 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In his wake, the interpretation of…](https://sms4smile.com/quotes/henning-genz/the-interpretation-of-apparent-long-distance-action-by-means-of/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“The quantity that physicists call the specific heat of a substance is defined as the amount of energy needed to raise the temperature of…](https://sms4smile.com/quotes/henning-genz/the-quantity-that-physicists-call-the-specific-heat-of-a-substance-is/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“To gain any intuitive understanding of the breakdown of this ultimate symmetry through vacuum effects at the critical 10^-44 seconds after the Big Bang,…](https://sms4smile.com/quotes/henning-genz/to-gain-any-intuitive-understanding-of-the-breakdown-of-this-ultimate/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“To illustrate this relation, think of a game of table tennis. As the ball hits the table, it will bounce up and down. 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We know this is true;…](https://sms4smile.com/quotes/henning-genz/what-really-transcends-our-understanding-is-the-mechanism-that/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“Chaotic or disordered distributions are symmetrical on the average. An observer cannot conclude anything about his location from looking around him. An example is…](https://sms4smile.com/quotes/henning-genz/chaotic-or-disordered-distributions-are-symmetrical-on-the-average-an/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“The hotter a substance, the faster and the less ordered its molecular motion, and the larger the momentum with which molecules collide. Above 0…](https://sms4smile.com/quotes/henning-genz/the-hotter-a-substance-the-faster-and-the-less-ordered-its-molecular/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“This elementary process is symbolically illustrated in figure 59c: A photon becomes an electron-positron pair; inversely, an electron and a positron can combine into…](https://sms4smile.com/quotes/henning-genz/this-elementary-process-is-symbolically-illustrated-in-figure-59c-a/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“John Maddox, the editor of the British journal Nature, had immediately suggested that the minister should be told that the Higgs boson can be…](https://sms4smile.com/quotes/henning-genz/john-maddox-the-editor-of-the-british-journal-nature-had-immediately/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“At first glance, it may appear odd that the black hole loses mass upon absorbing another mass-that of the electron. Actually, this seeming paradox…](https://sms4smile.com/quotes/henning-genz/at-first-glance-it-may-appear-odd-that-the-black-hole-loses-mass-upon/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) > [“We can now infer that at this initial cooldown of the universe across the critical temperature of 10^15 degrees, a mini planetary system might…](https://sms4smile.com/quotes/henning-genz/we-can-now-infer-that-at-this-initial-cooldown-of-the-universe-across/) [Henning Genz](https://sms4smile.com/quotes/author/henning-genz/) [Explore all 109 Henning Genz quotes ](https://sms4smile.com/quotes/author/henning-genz/) ## More Big bang quotes > [About 120 million of us place the big bang 2,500 years after the Babylonians and Sumerians learned to brew beer. If our polls are…](https://sms4smile.com/quotes/sam-harris/about-120-million-of-us-place-the-big-bang-2-500-years-after-the/) [Sam Harris](https://sms4smile.com/quotes/author/sam-harris/) > [Tune your television to any channel it doesn't receive and about 1 percent of the dancing static you see is accounted for by this…](https://sms4smile.com/quotes/bill-bryson/tune-your-television-to-any-channel-it-doesn-t-receive-and-about-1/) [Bill Bryson](https://sms4smile.com/quotes/author/bill-bryson/) > [ Bill Prady and Chuck Lorre, the guys who run that show \[Big Bang Theory\], are really funny and really smart, and the cast is… ](https://sms4smile.com/quotes/brent-spiner/bill-prady-and-chuck-lorre-the-guys-who-run-that-show-big-bang-theory/) [Brent Spiner](https://sms4smile.com/quotes/author/brent-spiner/) > [Sure, nobody will make a fortune if we figure out why the Big Bang happened. But just about everyone would like to know.](https://sms4smile.com/quotes/seth-shostak/sure-nobody-will-make-a-fortune-if-we-figure-out-why-the-big-bang/) [Seth Shostak](https://sms4smile.com/quotes/author/seth-shostak/) > [“The Creation of the World or Omniverse is the Creation or Recreation of the Absolute itself through the two poles, two “sides” of its…](https://sms4smile.com/quotes/dejan-stojanovic/the-creation-of-the-world-or-omniverse-is-the-creation-or-recreation/) [Dejan Stojanovic](https://sms4smile.com/quotes/author/dejan-stojanovic/) > [All that stuff I was taught about evolution, embryology, Big Bang theory, all that is lies straight from the pit of hell. It's lies…](https://sms4smile.com/quotes/paul-broun/all-that-stuff-i-was-taught-about-evolution-embryology-big-bang/) [Paul Broun](https://sms4smile.com/quotes/author/paul-broun/) > [For example, if the big bang had been one-part-in-a billion more powerful, it would have rushed out too fast for the galaxies to form…](https://sms4smile.com/quotes/robert-lanza/for-example-if-the-big-bang-had-been-one-part-in-a-billion-more/) [Robert Lanza](https://sms4smile.com/quotes/author/robert-lanza/) > [God created... light anddark, heaven and hell-science claims the same thing as religion, that the Big Bang createdeverything in the universe with an opposite."Including…](https://sms4smile.com/quotes/dan-brown/god-created-light-anddark-heaven-and-hell-science-claims-the-same/) [Dan Brown](https://sms4smile.com/quotes/author/dan-brown/) > [Scientists estimate the universe unfolded from its state of infinite destiny\* - a moment commonly referred to as "the big bang" - approximately 1.3-2…](https://sms4smile.com/quotes/mark-z-danielewski/scientists-estimate-the-universe-unfolded-from-its-state-of-infinite/) [Mark Z. Danielewski](https://sms4smile.com/quotes/author/mark-z-danielewski/) > [Chemistry seems to be pretty much nailed down, and biology gains ground all the time. But physics seems to be mired in idle rumination.…](https://sms4smile.com/quotes/jeremy-hardy/chemistry-seems-to-be-pretty-much-nailed-down-and-biology-gains/) [Jeremy Hardy](https://sms4smile.com/quotes/author/jeremy-hardy/) > [The big bang made the foundations for the 1st atoms](https://sms4smile.com/quotes/tiesto/the-big-bang-made-the-foundations-for-the-1st-atoms/) [Tiesto](https://sms4smile.com/quotes/author/tiesto/) > [“Only three of the naturally occurring elements were manufactured in the big bang. The rest were forged in the high-temperature hearts and explosive remains…](https://sms4smile.com/quotes/neil-degrasse-tyson/only-three-of-the-naturally-occurring-elements-were-manufactured-in/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) > [Our entire universe emerged from a point smaller than a single atom. Space itself exploded in a cosmic fire, launching the expansion of the…](https://sms4smile.com/quotes/neil-degrasse-tyson/our-entire-universe-emerged-from-a-point-smaller-than-a-single-atom/) [Neil deGrasse Tyson](https://sms4smile.com/quotes/author/neil-degrasse-tyson/) > [A proponent of the big bang theory, at least if he is an atheist, must believe that the matter of the universe came from…](https://sms4smile.com/quotes/anthony-john-patrick-kenny/a-proponent-of-the-big-bang-theory-at-least-if-he-is-an-atheist-must/) [Anthony John Patrick Kenny](https://sms4smile.com/quotes/author/anthony-john-patrick-kenny/) > [“Science is a human construct. Scientific laws are as valid as our understanding at any particular moment. Scientific laws are not absolute. Scientific laws…](https://sms4smile.com/quotes/dejan-stojanovic/science-is-a-human-construct-scientific-laws-are-as-valid-as-our/) [Dejan Stojanovic](https://sms4smile.com/quotes/author/dejan-stojanovic/) [Browse all 442 Big bang quotes ](https://sms4smile.com/quotes/about/big-bang/) ```json { "@context": "https://schema.org", "@graph": [ { "@type": "Quotation", "text": "“Let's return to Archytas's staff and to the expanding Universe. A javelin that is thrown straight upward will drop back down a long time before we can sensibly ask the question about the edge of the universe. The javelin cannot escape the gravity of Earth. A spacecraft that runs out of propellant only after it reaches the velocity that permits escape from the gravitational pull of our solar system will continue on its path, but it will remain inside our galaxy. The Milky Way's gravitational field holds onto it. Proceeding like this, we pass, from a practical problem to a fundamental question. Can there be objects that may escape our group of galaxies and that will ultimately leave our universe altogether? The answer must be no. The universe, after all, keeps expanding. Light that reaches us today was emitted shortly after the birth of the universe; its headwaters are moving away from us with a velocity close to that of light. There is no light older than what originated at the time of the Big Bang. 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