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Interested in Big Bang?


PCS

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So ... one day we figure out the how's and when's as to how and when the Big Bang, um, banged. Big deal. Doesn't help us with the Why. <br /><br />And so we see to the very edges of the visible universe, and look real hard ... and we see that it is dark out there. Big deal. We already know that inter-galactic space is a Big Place ... and it took us until 15 minutes ago, in terms of human history, just to get to where we could conceive of other galaxies. Actually seeing them just happened about 30 seconds ago. Humbug, I say. All that peering intently to the edges of the visible universe ... perhaps it suggests nothing more than that inter-universal space is a Really Big Place. <br /><br />Yawn ... even that doesn't help with the Why. <br /><br />The Why ... that's what makes my spine tingle. So I guess I'm not too worried that we'll discover all the Truths next week and all be, like, bored. <img border="0" title="" alt="[smile]" src="smile.gif" />

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Boy, try and post a little facinating,(or so I thought), tidbit there and some guy eating chocolate donuts comes in and........ <img border="0" alt="[sleep]" title="" src="graemlins/sleep.gif" /> . Geeeez. <img border="0" title="" alt="[smile]" src="smile.gif" />

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OM, It may be more than just a question of the space being very big outside of our known universe.<br /><br />We can kind of guess that when we see a falling star, the star has in fact been gone for a very long time. It just took a while for the light of the falling star to reach us. <br /><br />So what if the edge of the known universe isn't because there is nothing out there, but rather the light from way out there just hasn't gotten to us yet? Theoretically, if everything came into being at once, we might not see the light from the farthest places for a really long time. I guess it would be possible to guess the approx time of the big bang be how far we can see.

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Apologies in advance, becaise I'm not gonna edit this, just write it quick while I have a couple of minutes. No doubt it'll ramble ... even for me. <br /><br />*<br /><br />"OM, It may be more than just a question of the space being very big outside of our known universe."<br /><br />Oh, absolutely. Absolutely. I wasn't suggesting that's "all" it could be, just throwing out one idea I find intriguing. There are so many more ... <img border="0" title="" alt="[smile]" src="smile.gif" /> <br /><br />"We can kind of guess that when we see a falling star, the star has in fact been gone for a very long time. It just took a while for the light of the falling star to reach us."<br /><br />Yes, it takes light from distant starts & galaxies a very long time indeed to reach us. Some stars we "see" today surely died and went dark eons ago, but light they emitted eons ago is just reaching us now. And it's also quite likely that an "empty spot" in the space we see from Earth today may actually house a massive young star whose light simply has not reached us yet. Indeed, it is a Very Big Place out there. <br /><br />Just for the record, though, falling (or shooting) stars are not really a good example. Falling stars are not "stars" at all, but meteorites, hitting the Earth's atmosphere and burning up. The streak we see is the brief, incandescent event of their chemicals reacting to the heat & friction and breaking up. <br /><br />"So what if the edge of the known universe isn't because there is nothing out there, but rather the light from way out there just hasn't gotten to us yet?"<br /><br />Exactly what I was suggesting in my earlier post. It would not surprise me in the slightest if in the next few years, when the successors to Hubble let us see farther by orders of magnitude, we may in fact look out beyond the "edge of the visible universe" we can see today, across another inconceivably vast stretch of darkness ... and see other "universes" just like ours, expanding towards US. I'd get a brief spine-tingle out of that. <img border="0" title="" alt="[smile]" src="smile.gif" /> <br /><br />"Theoretically, if everything came into being at once, we might not see the light from the farthest places for a really long time."<br /><br />Agreed. Although today's science (telescopes) has allowed us to see outwards to galaxies that are, I believe (don't have the latest numbers in front of me) 13 to 14 billion light-years away, and then ... nothing. Our telescopes are capable, even today, of seeing farther, but there doesn't appear to BE anything else visible beyond those most distant galaxies. <br /><br />So if nothing else, there appears to be an "empty space" of uncertain size/depth beyond that 13-14 billion light-year marker that is essentially empty (of visible matter, anyway). What we don't know is just how BIG that emptiness is. That's what I was cryptically alluding to with my comment in the earlier post about "inter-universal" space. <br /><br />And like I said above in this post, it may well be that there are other "universes" beyond our current telescopes' range that we'll get to see in the next generation or two. Won't really change anything, when you think about it ... just make the "visible universe" all that much more grand. At some point, that line of thinking hits a wall, though ... because it seems you can always build a more powerful telescope. If we DO in fact "see" something beyond the current dark barrier, it would follow that someday we'll see to the edges of THAT, and then wonder if we don't need still more lens-power. <img border="0" alt="[doh]" title="" src="graemlins/doh.gif" /> <br /><br />"I guess it would be possible to guess the approx time of the big bang be how far we can see." <br /><br />True. The best guess today is the 13-14 billion year time-frame ... based on what we can "see today. Tomorrow, that may change.<br /><br />And all we've talked about so far are other "universes" sharing the basic physical properties of our own, ones that we may only not know about yet because our eyes haven't fully adjusted to the dark (so to speak). I suppose, if we decide to go off on some serious tangents, we could begin to postulate on the possible existence of "universes" in other dimensions, or other categories we cannot yet even begin to conceive.<br /><br />Hey ... maybe we'll get lucky, and Someone or Something will come along next week and explain It all to us. Think of the money we'd save on telescopes. <img border="0" title="" alt="[smile]" src="smile.gif" /> <br /><br />Now, off to find another donut.<br /> <br /> <small>[ March 27, 2002, 03:25 PM: Message edited by: Om ]</small>

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Another fun thought about what may be beyond that 13-14 billion light year barrier: <br /><br />Maybe our entire visible universe is just one "ripple" in an even Bigger Bang than we are used to thinking about. You know, like in a pond, only 3-d. <br /><br />You toss a rock in the middle, the concentric circles of the shock wave begin to head outwards from center. "Our" universe could just one such ripple, and the apparent darkness beyond where our present technology can see could be nothing more that the space between us and the next one, in an infinite number of other ripples (I believe that would make us a cosine, right Danny?).<br /><br />Ooh! Ooh! Or maybe ... <img border="0" alt="[cool]" title="" src="graemlins/cool.gif" /><br /> <br /> <small>[ March 27, 2002, 03:37 PM: Message edited by: Om ]</small>

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"Ripples in time Captain". Well, okay in this case....space. Now that would cause one to be tingley all over. Though I still get that way just looking the Hooter Gi...ahem I mean the pictures of other galaxies in "our" universe. Too possibley see images of our universe in its infancy is an amazing thing to me. To maybe see others as well is.... whoa. Either that or find someone looking back.

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The only Big Bang I'm interested in.... is banging Mary Lou after dinner, this coming Saturday night. <img border="0" alt="[laugh]" title="" src="graemlins/laugh.gif" /> <img border="0" alt="[laugh]" title="" src="graemlins/laugh.gif" /> <img border="0" alt="[laugh]" title="" src="graemlins/laugh.gif" /> <img border="0" alt="[laugh]" title="" src="graemlins/laugh.gif" /> <img border="0" alt="[laugh]" title="" src="graemlins/laugh.gif" />

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Hang in there boys, High Energy Mathematical Physicist here to the uh, rescue....<br /><br />So its been a while since i've posted, but after hearing this thread come up, i couldn't help but chime in; after all, this is what I do...<br /><br />In response to om's first post, i would argue that the "what" really is the important issue. What do you mean when you say why? No matter what explanation anyone gives, you can always ask why that explanation is the way it is. We all played this game when we were 4, and it is equally valid now. <br /><br />Anyway, here is one of the questions that many physicsts today ponder... <br /><br />how many dimensions do we live in? <br /><br />To the naked eye it appears that we live in 4 dimensions (commonly written 3+1), with one of these having a quirky property (time really is different). If we put all of our theories down on a space of dimension 3+1 we get stuff that works out most of the time. We know what happens when protons bump into neutrons or electrons. In other words, we can calculate all of this if we have a big enough computer. <br /><br />This is not true for gravity. If we put gravity (as we know it) down on a 3+1 dimensional space, it blows up. What's curious is that these problems go away when me move to larger dimensions, say 6 or 13. So why do we beleive we know how to put gravity on a 3+1 dimensional space?<br /><br />Gravity is the most interesting of all of the forces in nature since it is gravity which determines the structue of our space. From high school you probably remember the talk of massive objects bending space. Thus an understanding of gravity is fundamentally tied to the questions you guys are asking on this board. <br /><br />(is anyone still reading this????)<br /><br />But how do we begin writing down gravity? Well, the first thing we do is admit that we have no idea how gravity really works. If we did, we would have a theory valid at arbitrarily short distance without any evidence for it since we can't do infinitely small experiments. But, we do know exactly how the theory must behave at long distances, say the scale from the earth to the sun. Actually current experiments have the length down to about 1cm. <br /><br />(this length represents the length scale associated with a change in the gravitational field) <br /><br />So we require that our theory look like gravity beneath this distance, and then we write down the most general extension to the theory possible. The fun part is that as i said above, no has done this. Not only that, people are becoming fairly certian that it cannot be done.<br /><br />which brings us to the big bang.<br /><br />A current model suggests that Gravity is actually an interaction which propogates in n + 3 + 1 dimensions (n>0). We then confine all of our normal fields (that's us) to moveonly in the space of dimension 3+1. We can imagine this as a sort of sheet floating around inside a volume, except the dimensions are higher. What happens when two of these sheets collide? Big Bang.<br /><br />Anyway, this model is where a lot of current research is going right now. I'm currently working on this kind of stuff at caltech. I don't claim to fully understand any of this, so too many why's and i will break down, but for those interested i thought you might like to see what it looks like from where i'm standing.<br /><br />-DB<br /> <br /> <small>[ March 28, 2002, 12:53 AM: Message edited by: DrunkenBoxer ]</small>

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That's what you do for a living? I think I begin to understand your desire for drunk boxing :-)<br /><br />Actually that's pretty cool stuff. If there are more than 4 dimensions, does our know universe move through any of the other dimensions, or is everything more or less unmoving. In you sheet of paper in a volume, I guess that would be like a stack of papers. That way we avoid moving one sheet into another with more big bangs.

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As an add on, wouldn't the lack of motion in any other dimensions make it extremely difficult<br />to perceive the other dimentions?<br /><br />After all, I contemplate hieght, width, and length dimensions by my ability to move in space. <br />Time I understand becaus I move thorugh it even though the trip is one way.<br />All of these things I only understand because I am mobile in these dimensions.<br /> <br /> <small>[ March 28, 2002, 08:53 AM: Message edited by: gbear ]</small>

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These sheets would be highly dynamic. Essentially, Every time the gravitational field changes, the sheets would change. AS the sheets bend, energy is stored and released, corresponding to the gravitational energy in the space at that point. But it's not just the sheets that move in this way, the whole space is dynamic. In a way, the movement of the sheet is just a reflection of the movement of the entire space. <br /><br />This brings us to your second question. How do we probe this extra space? As I said in the post most particles (fields) are constrained to move only in the sheet, but gravity is not. Therefore, we can use gravitational experiments to determine the properties of this extra space. <br /><br />The trouble is that gravity is so weak that experiments are real hard to do. IF we try to measure the gravitational force between a neutron and another neutron, we get zero. There are other ways to measure this stuff, but its hard and expensive. Anyway, given our current understanding these dimensions would have to be smaller than a cm. They would be what we call "rolled up."<br /><br />The drunk boxing just keeps the ivory towerness from getting to ya.<br /><br />-DB

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DB, my brother, such gravitas ... you're such a scientist.. <img border="0" title="" alt="[smile]" src="smile.gif" /> <br /><br />Don't have time to do this justice today, so here's what I was trying to say:<br /><br />The "What" - the physics of it all. How the physics of it all works. Looking out with telescopes and looking in with microscopes. Accelerating particles. Hypothesizing and experimenting. Trying to find the Unifying Theory that will let us speak knowledgeably about what we can actually see and feel around us. What smart guys like you, happily, are working on. <br /><br />The "Why" - the question of whether the "what" you guys are working on is all just a Happy Accident, or if Someone or Something designed it all. And if so, to what end. You know, the unquantifiable stuff that laypeople with no appreciable scientific skills, but active imaginations and voracious curiosity -- like me -- find even more compelling than the "what," and sit around endlessly pontificating upon. <img border="0" title="" alt="[smile]" src="smile.gif" /> <br /><br />Yes, I know the lines blur between the two at some point, and my hope is that you smart guys will find the Key at some point. I love the "what" ... it's quantifiable. And we're making progress. <br /><br />But I'm impatient, and I'm absolutely crazy over the "why" ... to me, it's the Ultimate Question. And it's one that flows quite nicely at 3 in the morning when the keg, and your friend's minds, are also flowing well. <br /><br />I'll drink to you tonight. <img border="0" alt="[cool]" title="" src="graemlins/cool.gif" />

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And here I am thinking 3+1=4. Silly me. So, between the guys looking at or through the scopes and you fellows with the math/physics degrees D.B.,(I assume there is some type of cooperation there, or some guys who do both.), just maybe there will be answers to how, what, and maybe even when. Why? I ask myself that question, but on a far, far simpler scale than this every now an then. Though with those answered, there maybe a little insight as to why. Om is right though, it is the ultimate question. And certainly would be the ultimate answer.<br /><br />Question D.B. Sort of a chicken and the egg thing. I understand that sometimes there is a mathematical theory that comes first and then scientist go through cartwheels trying to prove it practically. In the case of the big band and other things involing the cosmos, are there times that the telescopes and other devices peering into space "see" things that force fellows like you to prove them or figure them out mathematically or vise versa? That make any since whatsoever?<br /> <br /> <small>[ March 28, 2002, 09:49 PM: Message edited by: Park City Skins ]</small>

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The reaon we write 3+1 is that time is different, the +1 reminds us of that. Trace out a path that light takes in 4 dimensions. In a given "length" of the path in four dimensions L, we can separate it into a traversal of each of the four dimensions. t, d1, d2, d3. (This is similar to breakingh up a distance into north and south components) Now the speed of light is given by: <br /><br />c^2 = t x t / (d1xd1 + d2xd2 + d3xd3 + d4xd4)<br /><br />the point is that this is asymetric in time. So that time really is different, as all light paths follow the above formula. <br /><br />On to your next question...<br /><br />Earlier in physics, say up until about 1950, there was no doubt that experiment was leading the way, but more recently those lines have blurred.<br /><br />In some areas, such as gravity, the current work is mostly theoretical. The biggest reason why most of this work is theoretical is that experiments today are expensive. Governements don't want to spend 1 billion dollars to build a supercollider that would test our theories up to ridiculously high energies. <br /><br />Another reason why theory is doing so much in gravity is that there is so much work to be done. As i said, gravity has thoeretical difficulties. Even the modest amount of data we currently have is too much for us. We cannot figure out how to design a theory which fits gravity at all. <br /><br />Sometimes experiments come to the rescue. by providing new information they point towards possible solutions of existing problems. Sometimes theorists see patterns emerging in the theories and they point the experimenters in an interesting direction. <br /><br />But right now we're at an impasse of sorts. It's been a long time since any experiment has shown anything that was not predicted by the theorists. The most exciting experimental development has been the realization that one of our elementary paritlces, the neutrino, may actually have mass. If so, it would contradict our standard model, but only in a trivial way. <br /><br />So the world of experiment, to me at least, seems pretty bleak right now. No one wants to fund the next super collider, the last one was proposed for texas and got shut down by the senate. (somewhere around 95-98). <br /><br />As for the telescope experiments, most of it is archaeolgy. Mostly they look at stuff which needs to be undestood at a far less basic level than the work we do. Most of the explanations they come up with rest on the framework of what we do, so they don't give us any new information. However, they do get some information. 1 notable piece of data is the acceleration rate of the universe. This is interesting because it is one peice of data which current thoeries do not fit. In fact, this one piece of data seems to indicate that it is impoosible for gravity to propogate in only our 3+1 dimensions. This is a problem that i am currently working on. <br /><br />Anyway, hope this answers your questions and raises more.<br /><br />-DB

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  • 8 years later...

http://cosmiclog.msnbc.msn.com/_news/2010/11/04/5408660-physicists-get-set-for-little-big-bangs

Physicists get set for little big bangs

The world's biggest particle collider has switched over from shooting beams of protons to shooting heavy ions -- leading to experiments that could cook up the kind of "soup" produced by the big bang. And even before those experiments have begun, critics have cooked up a fresh batch of doomsday talk as well.

For the past year, the Large Hadron Collider has been smashing protons together at progressively higher energies, 300 feet (100 meters) below ground at the French-Swiss border, in a ring-shaped tunnel that measures 17 miles (27 kilometers) around. A milestone was reached last month when the beams' luminosity hit its target for the year.

..Current theory suggests that the whole universe existed as a dollop of super-hot quark-gluon plasma in the first few millionths of a second after the big bang. Since then, quarks have been virtually impossible to pull apart -- but an ion-smasher in New York, known as the Relativistic Heavy-Ion Collider or RHIC, is thought to have done it five years ago. Such experiments help physicists understand exactly how the universe was, and is, put together.

CERN says the LHC should be able to collide heavy ions with energy levels 28 times higher than those achieved at RHIC. Some theorists have suggested that at those energies, the big bang soup would no longer exist as a liquid, but as a gas. And so, for the next few weeks, the LHC's spotlight will turn to a huge detector called ALICE (which stands for "A Large Ion Collider Experiment").

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The biggest reason why most of this work is theoretical is that experiments today are expensive. Governements don't want to spend 1 billion dollars to build a supercollider that would test our theories up to ridiculously high energies.
So the world of experiment, to me at least, seems pretty bleak right now. No one wants to fund the next super collider, the last one was proposed for texas and got shut down by the senate. (somewhere around 95-98).

Would love to see Ignatius come back and give us an update on his work and what he thinks about the LHC. I'd imagine a lot has changed since 2002!

1 notable piece of data is the acceleration rate of the universe. This is interesting because it is one peice of data which current thoeries do not fit. In fact, this one piece of data seems to indicate that it is impoosible for gravity to propogate in only our 3+1 dimensions. This is a problem that i am currently working on. Anyway, hope this answers your questions and raises more

Does this relate to what we now call dark energy?

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