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Thread: Hottest moment that created the Big Bang recreated

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    Senior Member Raphael's Avatar
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    Hottest moment that created the Big Bang recreated

    EASY PEEZY

    As the Big Bang theory goes, somewhere around 13.8 billion years ago the universe exploded into being, as an infinitely small, compact fireball of matter that cooled as it expanded, triggering reactions that cooked up the first stars and galaxies, and all the forms of matter that we see (and are) today. Physicists simulated the critical “reheating” period that kickstarted the Big Bang in the universe’s first fractions of a second.


    Just before the Big Bang launched the universe onto its ever-expanding course, physicists believe, there was another, more explosive phase of the early universe at play: cosmic inflation, which lasted less than a trillionth of a second. During this period, matter — a cold, homogeneous goop — inflated exponentially quickly before processes of the Big Bang took over to more slowly expand and diversify the infant universe.


    Recent observations have independently supported theories for both the Big Bang and cosmic inflation. But the two processes are so radically different from each other that scientists have struggled to conceive of how one followed the other.

    Now physicists at MIT, Kenyon College, and elsewhere have simulated in detail an intermediary phase of the early universe that may have bridged cosmic inflation with the Big Bang. This phase, known as “reheating,” occurred at the end of cosmic inflation and involved processes that wrestled inflation’s cold, uniform matter into the ultrahot, complex soup that was in place at the start of the Big Bang.


    “The postinflation reheating period sets up the conditions for the Big Bang, and in some sense puts the ‘bang’ in the Big Bang,” says David Kaiser, the Germeshausen Professor of the History of Science and professor of physics at MIT. “It’s this bridge period where all hell breaks loose and matter behaves in anything but a simple way.”


    Kaiser and his colleagues simulated in detail how multiple forms of matter would have interacted during this chaotic period at the end of inflation. Their simulations show that the extreme energy that drove inflation could have been redistributed just as quickly, within an even smaller fraction of a second, and in a way that produced conditions that would have been required for the start of the Big Bang.


    he team found this extreme transformation would have been even faster and more efficient if quantum effects modified the way that matter responded to gravity at very high energies, deviating from the way Einstein’s theory of general relativity predicts matter and gravity should interact.

    “This enables us to tell an unbroken story, from inflation to the postinflation period, to the Big Bang and beyond,” Kaiser says. “We can trace a continuous set of processes, all with known physics, to say this is one plausible way in which the universe came to look the way we see it today.”



    The team’s results appear today in Physical Review Letters. Kaiser’s co-authors are lead author Rachel Nguyen, and John T. Giblin, both of Kenyon College, and former MIT graduate student Evangelos Sfakianakis and Jorinde van de Vis, both of Leiden University in the Netherlands.





    The theory of cosmic inflation, first proposed in the 1980s by MIT’s Alan Guth, the V.F. Weisskopf Professor of Physics, predicts that the universe began as an extremely small speck of matter, possibly about a hundred-billionth the size of a proton. This speck was filled with ultra-high-energy matter, so energetic that the pressures within generated a repulsive gravitational force — the driving force behind inflation. Like a spark to a fuse, this gravitational force exploded the infant universe outward, at an ever-faster rate, inflating it to nearly an octillion times its original size (that’s the number 1 followed by 26 zeroes), in less than a trillionth of a second.



    Kaiser and his colleagues attempted to work out what the earliest phases of reheating — that bridge interval at the end of cosmic inflation and just before the Big Bang — might have looked like.


    “The earliest phases of reheating should be marked by resonances. One form of high-energy matter dominates, and it’s shaking back and forth in sync with itself across large expanses of space, leading to explosive production of new particles,” Kaiser says. “That behavior won’t last forever, and once it starts transferring energy to a second form of matter, its own swings will get more choppy and uneven across space. We wanted to measure how long it would take for that resonant effect to break up, and for the produced particles to scatter off each other and come to some sort of thermal equilibrium, reminiscent of Big Bang conditions.”



    The team’s computer simulations represent a large lattice onto which they mapped multiple forms of matter and tracked how their energy and distribution changed in space and over time as the scientists varied certain conditions. The simulation’s initial conditions were based on a particular inflationary model — a set of predictions for how the early universe’s distribution of matter may have behaved during cosmic inflation.


    The scientists chose this particular model of inflation over others because its predictions closely match high-precision measurements of the cosmic microwave background — a remnant glow of radiation emitted just 380,000 years after the Big Bang, which is thought to contain traces of the inflationary period


    The simulation tracked the behavior of two types of matter that may have been dominant during inflation, very similar to a type of particle, the Higgs boson, that was recently observed in other experiments.

    Before running their simulations, the team added a slight “tweak” to the model’s description of gravity. While ordinary matter that we see today responds to gravity just as Einstein predicted in his theory of general relativity, matter at much higher energies, such as what’s thought to have existed during cosmic inflation, should behave slightly differently, interacting with gravity in ways that are modified by quantum mechanics, or interactions at the atomic scale.

    In Einstein’s theory of general relativity, the strength of gravity is represented as a constant, with what physicists refer to as a minimal coupling, meaning that, no matter the energy of a particular particle, it will respond to gravitational effects with a strength set by a universal constant.



    However, at the very high energies that are predicted in cosmic inflation, matter interacts with gravity in a slightly more complicated way. Quantum-mechanical effects predict that the strength of gravity can vary in space and time when interacting with ultra-high-energy matter — a phenomenon known as nonminimal coupling.

    Kaiser and his colleagues incorporated a nonminimal coupling term to their inflationary model and observed how the distribution of matter and energy changed as they turned this quantum effect up or down.

    In the end they found that the stronger the quantum-modified gravitational effect was in affecting matter, the faster the universe transitioned from the cold, homogeneous matter in inflation to the much hotter, diverse forms of matter that are characteristic of the Big Bang.


    By tuning this quantum effect, they could make this crucial transition take place over 2 to 3 “e-folds,” referring to the amount of time it takes for the universe to (roughly) triple in size. In this case, they managed to simulate the reheating phase within the time it takes for the universe to triple in size two to three times. By comparison, inflation itself took place over about 60 e-folds.

    “Reheating was an insane time, when everything went haywire,” Kaiser says. “We show that matter was interacting so strongly at that time that it could relax correspondingly quickly as well, beautifully setting the stage for the Big Bang. We didn’t know that to be the case, but that’s what’s emerging from these simulations, all with known physics. That’s what’s exciting for us.”



    “There are hundreds of proposals for producing the inflationary phase, but the transition between the inflationary phase and the so-called “hot big bang” is the least understood part of the story,” says Richard Easther, professor of physics at the University of Auckland, who was not involved in the research. “This paper breaks new ground by accurately simulating the postinflationary phase in models with many individual fields and complex kinetic terms. These are extremely challenging numerical simulations, and extend the state of the art for studies of nonlinear dynamics in the very early universe.”


    Cosmic Microwave Background (CMB) spectrum plotted in waves per centimeter vs. intensity. The solid curve shows the expected intensity from a single temperature blackbody spectrum, as predicted by the hot Big Bang theory. A blackbody is a hypothetical body that absorbs all electromagnetic radiation falling on it and reflects none whatsoever.


    This research was supported, in part, by the U.S. Department of Energy and the National Science Foundation.

    Contacts and sources:

    Jennifer Chu , MIT

    Lab Helper , Raphael from Forum Garden .

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    Re: Hottest moment that created the Big Bang recreated

    I for one appreciate these kinds of threads, however, I'd like to suggest quoting a lesser amount of the article and leaving a link for those who would choose to read the entire thing. It makes scrolling back up a lot easier. And, you know, batteries don't last as long as they used to. Just a suggestion.
    “Those who can make you believe absurdities can make you commit atrocities,”
    Voltaire

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    Sink back into the ocean

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    Senior Member Raphael's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    I understand that attention span has dropped significantly and that for many people reading a whole book is like being asked to climb a huge mountain on hands and knees wearing no clothes .

    But really ?!?!

    Beginners at reading more than two paragraphs in one sitting might benefit from reading an OP like this as a project to be completed over a few days .

    They could reward themselves for completing their self defined daily reading module and give themselves a memorable treat upon final completion .

    Instead of playing video games or watching mindless TV , they could form self help groups with family and friends ( if they have any ) where they engage in non celebrity chat and non trivia and attempt to examine a difficult subject together .

    It is all about Mental Multiculturalism , to coin a new and dreadful term .

    But I am pleased you enjoyed it because you and I account for around 60% of many topic posts where the content might be described as 'serious' .

    Roll on Christmas !!

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    Senior Member Bryn Mawr's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    Quote Originally Posted by Raphael View Post
    I understand that attention span has dropped significantly and that for many people reading a whole book is like being asked to climb a huge mountain on hands and knees wearing no clothes .

    But really ?!?!

    Beginners at reading more than two paragraphs in one sitting might benefit from reading an OP like this as a project to be completed over a few days .

    They could reward themselves for completing their self defined daily reading module and give themselves a memorable treat upon final completion .

    Instead of playing video games or watching mindless TV , they could form self help groups with family and friends ( if they have any ) where they engage in non celebrity chat and non trivia and attempt to examine a difficult subject together .

    It is all about Mental Multiculturalism , to coin a new and dreadful term .

    But I am pleased you enjoyed it because you and I account for around 60% of many topic posts where the content might be described as 'serious' .

    Roll on Christmas !!
    It is not a case of attention span, it is a case of copyright law which allow you to quote a small part of an article as long as you link back to the original.

    Ahso is, quite rightly, trying to protect the Garden from the threat of legal action.

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    Re: Hottest moment that created the Big Bang recreated

    Quote Originally Posted by Bryn Mawr View Post
    trying to protect the Garden from the threat of legal action.
    Incidentally, i just remembered about that insurance many years ago. Is that still available? Is it useful?
    “Those who can make you believe absurdities can make you commit atrocities,”
    Voltaire

    I have only one thing to do and that's
    Be the wave that I am and then
    Sink back into the ocean

    Fiona Apple

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    Proudly humble LarsMac's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    I love it when people who accuse others of being intellectually lazy can't find the time to follow process.

    [just sayin']
    "The trouble with people isn't that they don't know, but that they know so much that ain't so." - Will Rogers
    "Truth isn't Truth" - Rudy Giuliani

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    Proudly humble LarsMac's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    It is also about giving credit where it is due.

    Science Daily News: Putting the 'bang' in the Big Bang
    "The trouble with people isn't that they don't know, but that they know so much that ain't so." - Will Rogers
    "Truth isn't Truth" - Rudy Giuliani

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    Senior Member Bryn Mawr's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    Quote Originally Posted by Ahso! View Post
    Incidentally, i just remembered about that insurance many years ago. Is that still available? Is it useful?
    I’m going senile, I can’t remember!

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    Re: Hottest moment that created the Big Bang recreated

    Quote Originally Posted by Bryn Mawr View Post
    I’m going senile, I can’t remember!
    Perhaps it was Tombstone. I gave a link to one of you for a sort of insurance that protects against those lawsuits.

    I'm beginning to also question my reality. Aging is a prison. Life is so cruel.
    “Those who can make you believe absurdities can make you commit atrocities,”
    Voltaire

    I have only one thing to do and that's
    Be the wave that I am and then
    Sink back into the ocean

    Fiona Apple

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    Senior Member Bryn Mawr's Avatar
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    Re: Hottest moment that created the Big Bang recreated

    Register to remove this ad.
    Quote Originally Posted by Ahso! View Post
    Perhaps it was Tombstone. I gave a link to one of you for a sort of insurance that protects against those lawsuits.

    I'm beginning to also question my reality. Aging is a prison. Life is so cruel.
    Ah, that’s a relief, not me :-)

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