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L'expansion de l'univers

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New Proof Unknown "Structures" Tug at Our Universe. "Dark flow" is no fluke, suggests a new study that strengthens the case for unknown, unseen "structures" lurking on the outskirts of creation. In 2008 scientists reported the discovery of hundreds of galaxy clusters streaming in the same direction at more than 2.2 million miles (3.6 million kilometers) an hour. This mysterious motion can't be explained by current models for distribution of mass in the universe. So the researchers made the controversial suggestion that the clusters are being tugged on by the gravity of matter outside the known universe. Now the same team has found that the dark flow extends even deeper into the universe than previously reported: out to at least 2.5 billion light-years from Earth. "It looks like a very coherent flow. " The find adds to the case that chunks of matter got pushed outside the known universe shortly after the big bang—which in turn hints that our universe is part of something larger: a multiverse.

Dark Flow's Extended Reach. What is the universe expanding into? What’s outside the universe? | Ask a Mathematician / Ask a Physicist. Physicist: Probably nothing. We do know that the universe doesn’t need anything to expand into, and we haven’t seen any evidence that there is anything outside of the universe. But there has still been some speculation. In the last hundred years physics has gotten pretty weird, and defining “universe” has become a little tricky. So, in what follows I’m defining the universe as “all the places that could be connected to one another by a sufficiently long rope” (never mind how the rope got there).

Having never been outside of the universe, it’s hard to discuss it with any certainty. Most of the theories about the outside of the universe fall into the “I can’t say you’re wrong for sure” category. We can say that space isn’t “made of anything”, and that it doesn’t need any kind of “higher space” to exist in. In a conversation about spacetime often as not you’ll have some unpleasant and unrepentant jackass drawing parallels to rubber or sheets or something else material. The Universe and Beyond. What lies beyond the universe? We are not sure but can theorize what lies beyond the universe that we know. Outside the bounds of our univsere may lie a "super" universe. Space outside space that extends infinitely into what our little bubble of a universe may expand into forever. Lying hundreds of billions of light years from us could be other island universes much like our own. But why cant we see them? It's a possibility that they are so far away that by the time the light of them reaches us, it may have lost so much energy that we cannot detect it or our universe may end by the time it reaches us.

Another theory is that we are creating space as our universe expands. Yet another is that we are stuck inside a black hole of a larger universe outside our own. In short, there are many theories about what may be out there. Wow! Really?: What's Outside The Universe? Bailey,When we were in Albuquerque you asked me what was beyond the edge of the Universe, and I didn't have a very good answer. To be honest, I felt like a baseball player that had practiced and practiced (I've read a lot of books and thought a lot about the same question myself), but suddenly I was standing in the outfield and a high fly ball was headed my way (your question)...and I dropped the ball.

Your question is a really good one and a very hard one to answer because the ideas aren't simple and they aren't easy to understand--even for me. But I've been thinking about what you asked, and I'm really, really glad you did becuase it made me think hard about the question again too. Next time we see each other, maybe we can talk about this more, but here's my answer: think about the earth. It's a big ball, and when you look toward the horizon it looks like you can see where the earth stops.

But you know from driving and flying that there's no edge. But be careful. Grandpa Tom P.S. The observable Universe and beyond. 26 August 2012Last updated at 19:07 ET By Anthony Aguirre Associate Professor of Physics at the University of California Anthony Aguirre believes the Cosmic Microwave Background - the left-over glow from the Big Bang - could give us clues to the Universe next door The further we look into space, the further back in time we go and the last thing we see is left-overs from the Big Bang. This pattern in the sky could give us clues to the Universe next door. The Universe that we can observe is fantastically large. Using state-of-the-art instruments, astronomers can see back through 13.7 billion years, viewing regions of space that — due to the cosmic expansion — are now about 45 billion light-years away.

At earlier times, the Universe was so dense that light could not propagate, so this distance forms a spherical boundary in all directions. Light from this shell arrives unimpeded, but stretched by the cosmic expansion into microwaves. The now fairly well-understood observiball is enormous. Metric expansion of space. Metric expansion is a key feature of Big Bang cosmology, is modeled mathematically with the FLRW metric, and is a generic property of the universe we inhabit.

However, the model is valid only on large scales (roughly the scale of galaxy clusters and above). At smaller scales matter has become bound together under the influence of gravitational attraction and such things do not expand at the metric expansion rate as the universe ages. As such, the only galaxies receding from one another as a result of metric expansion are those separated by cosmologically relevant scales larger than the length scales associated with the gravitational collapse that are possible in the age of the Universe given the matter density and average expansion rate. According to measurements, the universe's expansion rate was decelerating until about 5 billion years ago due to the gravitational attraction of the matter content of the universe, after which time the expansion began accelerating. Metric tensor[edit] What is the Universe Expanding Into? Come on, admit it, you’ve had this question. “Since astronomers know that the Universe is expanding, what’s it expanding into?

What’s outside of the Universe?” Ask any astronomer and you’ll get an unsatisfying answer. We give you the same unsatisfying answer, but really explain it, so your unsatisfaction doesn’t haunt you any more. The short answer is that this is a nonsense question, the Universe isn’t expanding into anything, it’s just expanding. The definition of the Universe is that it contains everything.

If something was outside the Universe, it would also be part of the Universe too. Either the Universe is infinite, going on forever, or its finite, with a limited volume. Representation of the timeline of the universe over 13.7 billion years, and the expansion in the universe that followed. A better analogy is the surface of an expanding balloon.

Imagine the balloon is inflating. You might imagine a growing circle and wonder what it’s expanding into. Related November 13, 2014. What is the universe expanding into? I am very confused about things my science book says about the expanding universe. Every book I have seen has defined the universe as "everything". If the universe is expanding what is it expanding into? It would have to expand into even more universe. I understand that the red spectra indicates that things are moving away from us but that is drifting not expanding, right? If you could help me to understand this, it would be appreciated. Thank you for your time. This is a very good question which is not at all easy to give a satisfactory answer to! Now, for those of you who want a more comprehensive discussion: Let me begin by saying that "expanding" isn't really the best word to describe what is happening to the universe, although that is the word that is often used - a word choice which I think leads to a lot of unnecessary confusion regarding what is already a difficult topic!

Now, someone puts the dough in the oven and it begins to expand. What is the distance between two galaxies? Nobel physics prize honours accelerating Universe find. 4 October 2011Last updated at 11:02 By Jason Palmer Science and technology reporter, BBC News The three researchers' work has led to an expanding knowledge of our Universe Three researchers behind the discovery that our Universe's expansion is accelerating have been awarded this year's Nobel prize for physics. Saul Perlmutter and Adam Riess of the US and Brian Schmidt of Australia will divide the prize. The trio studied what are called Type 1a supernovae, determining that more distant objects seem to move faster. Their observations suggest that not only is the Universe expanding, its expansion is relentlessly speeding up.

Prof Perlmutter of the University of California, Berkeley, has been awarded half the 10m Swedish krona (£940,000) prize, with Prof Schmidt of the Australian National University and Prof Riess of Johns Hopkins University's Space Telescope Science Institute sharing the other half. 'Weak knees' Prof Schmidt spoke to the Nobel commitee from Australia during the ceremony. Quand le cosmos s'organise. The Scale of the Universe. Big Crunch. Un article de Wikipédia, l'encyclopédie libre. En cosmologie, le Big Crunch est un des possibles destins de l'Univers. Il désigne l'effondrement de l'univers, c'est-à-dire une phase de contraction faisant suite à la phase d'expansion. C'est donc en quelque sorte un « Big Bang à l'envers », qui consiste à ramener le cosmos à son point de singularité d'origine annulant l'espace et le temps.

Vers la fin de cet effondrement, l'univers aura atteint une densité et une température gigantesques. Le Big Crunch[modifier | modifier le code] Représentation schématique du Big Crunch. L'univers est en expansion. Dans un univers fini (ou fermé), appelé donc à subir le Big Crunch, les équations montrent que la densité réelle de matière est supérieure à une quantité désignée sous le nom de densité critique, mesurant pour sa part le taux d'expansion[1]. On utilise à tort l'image suivante (hélas reprise par de très nombreux ouvrages de vulgarisation). Densité de l'univers[modifier | modifier le code] Spitzer mesure l’expansion de l’univers. Chaque seconde, chaque volume d'Univers de trois millions d'années-lumière de côté gagne 74 kilomètres... C'est le résultat d'une mesure récente de la constante de Hubble réalisée avec le satellite infrarouge Spitzer et portant sur dix étoiles céphéides de notre galaxie et plus 80 autres du Grand Nuage de Magellan.

La valeur mesurée - 74,3 km/s/Mpc (kilomètres par seconde et par mégaparsec, un parsec valant 3,26 années-lumière) - est proche de celle obtenue en 2011 dans le visible avec le télescope spatial Hubble par la même méthode : 73,8 km/s/Mpc. Chandelles standard Ce n'est pas un hasard si les céphéides ont été utilisées dans ces deux études. Autrement dit, mesurer leur rythme revient à mesurer leur luminosité intrinsèque, ce qui permet de déduire leur distance à partir de leur éclat apparent. L'étude du télescope Hubble portait sur 600 céphéides dans des galaxies parfois très lointaines. La fin d'un long débat. The Scale of the Universe.

Hubble law and the expanding universe. The proportionality between recession velocity and distance in the Hubble Law is called the Hubble constant, or more appropriately the Hubble parameter since it does depend upon time. In recent years the value of the Hubble parameter has been considerably refined, and the current value given by the WMAP mission is 71 km/s per megaparsec.

The recession velocities of distant galaxies are known from the red shift, but the distances are much more uncertain. Distance measurement to nearby galaxies uses Cepheid variables as the main standard candle, but more distant galaxies must be examined to determine the Hubble constant since the direct Cepheid distances are all within the range of the gravitational pull of the local cluster. Use of the Hubble Space Telescope has permitted the detection of Cepheid variables in the Virgo cluster which have contributed to refinement of the distance scale. Big Crunch. L'EXPANSION DE L'UNIVERS EST-ELLE INFINIE ?