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  1. #151
    blokesbloke blokesbloke is online now
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    Quote Originally Posted by Sailor View Post
    I think that, while it certainly reinforces the general notion of a Big Bang, the real significance of the discovery is its validation of Inflation Theory. Quite a few scientists had expressed doubts about Inflation. In fact I've just been reading a work by Penrose in which he was casting a very cold eye on it.
    For those looking for an explanation of the actual origin of the Universe, keep praying!
    But I've known inflation was a reality since I was a nioper and the price of the Beano and KitKats kept going up, even as my pocket money remained static!
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  2. #152
    gerhard dengler gerhard dengler is offline
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    Quote Originally Posted by JamieD View Post
    Essentially, it's like this. We know that something happened around 13.7 billion years ago because essentially the arrow of time moves in one direction, which allows us to look backwards with confidence. Coupled with the expansion of the universe, which we can and have been observing and measuring for a long time now, and many other forms of evidence such as that provided by the cosmic microwave background, we can essentially rewind the clock and see the "evolution" of the observable universe, and as you go back you get to a point where everything is essentially in the same space/time.

    When you explain this to people they often think that means all "matter" in the universe was in one space and time so they imagine all of the hundreds of billions of galaxies just squashed into a small space, but that's not how it is at all. At the moment when it all began, it was pure energy, not matter, matter formed after the big bang. Speaking of "big bang", it wasn't big... all of the energy in the observable universe was in a space much much smaller than an atom, and there was no bang... since sound is propagated through air, which is matter, which didn't exist yet anyway the words "big bang" were actually used as a derogatory term by opponents of the idea who instead believed the universe was static and infinite, always was, always will be etc.

    But it caught on as a name and it has been backed up by quite a lot of evidence since. The complicated part of it is trying to describe it before the basic laws of nature as we understand them even existed, and in such a way that matches observation. For example, the observable universe is isotropic in nature (it appears the same in all directions) and the cosmic microwave background radiation appears to distributed evenly. That was actually a problem for the model as trying to describe the big bang always would produce a universe that is not like that, but more curved and heterogeneous. but instead it appears flat and homogeneous. That's where the concept of inflation came from as a hypothesis, that in the earliest moments of the universe (im talking trillionths of trillionths of seconds) the expansion of the universe was, to put it mildly, rapid... as in many many MANY times faster than the speed of light. This rapid inflationary period, which was over quite quickly (though the universe has continued to expand just much more slowly), would explain why we observe the universe the way it is. So the next thing you have to do is find evidence of it and the so called "smoking gun" evidence would be inflationary gravitational waves that we should be able to detect in the CMB... and that's what was announced on Monday, that researchers are very confident they have found it.

    Now the research will be prodded and poked at by the physicists etc. everywhere looking for holes or anything else that might explain the experimental results.

    Even though that is still something that will continue to be heavily debated and researched, we still know that "something" of enormous importance to our universe (whether its the only universe.. or the big bang was just an event of local importance, we dont know) did occur around 13.7 billion years ago, and we can see the evidence for it everywhere. Even just looking at galaxies, we know enough now about the types of stars we have in the Universe and their life-cycles to be able to predict how long they will last before they collapse under gravity, we can tell how old stars are so we can look back in time to before they formed (or typically before the whole cluster of stars in the area formed). In that way, you can sort of "rewind" a galaxy back to its formation, and then before it. You can do this across the whole observable Universe right to the earliest galaxies (or rather, how they appeared at the time.. even our galaxy is about 12 billion years old!) and learn a LOT about their formation.

    The observable universe as a sort of evolutionary path to follow, and from the time of the first light in the Universe, when it wasn't opaque anymore, we can essentially follow a path from the (mostly) hydrogen formed from the energy released by the "big bang", to the first stars and then black holes, to the first galaxies (which pretty much all seem to have black holes right at the center, some of the oldest objects in the universe) and then through the life cycle of stars to give us the variety of stars we see, then planets and so on.

    In that way, the "big bang" event is not just kind of idea that might have happened... something DID happen.. we just call it the big bang because its as far back as we can account for.
    Thanks for this informative post.

    I read elsewhere that the evidence of this discovery has been with held for 3 years so that the evidence could be tested in as far as it can before the discovery has been published this weekend.
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  3. #153
    Toland Toland is offline
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    Quote Originally Posted by blokesbloke View Post
    But I've known inflation was a reality since I was a nioper and the price of the Beano and KitKats kept going up, even as my pocket money remained static!
    Kitkats were gick.
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  4. #154
    JamieD JamieD is offline

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    Quote Originally Posted by gerhard dengler View Post
    Thanks for this informative post.

    I read elsewhere that the evidence of this discovery has been with held for 3 years so that the evidence could be tested in as far as it can before the discovery has been published this weekend.
    From what I read they seemed to find what they were looking for quicker and easier than they expected, so they did spend a considerable amount of time ruling out other possibilities, but even at that, its real test will only come now.

    And no problem for the post, I'm not a physicist or cosmologist or anything, I just have always loved science so most of what I know is self-taught. I'm sure that some details of my post might be a slight bit off or glossed over, but the overall gist.... that we can plot a course back to the "big bang" by understanding a kind of cosmic evolution.... is pretty well backed up

    The earliest times in the Universe have always fascinated me. For example, here's a blog post I bookmarked some time ago that explains to some degree how we ended up with a Universe of mostly hydrogen, and how most of the nuclei of hydrogen and helium-4 were actually formed very quickly (though they didn't become atoms as we know them for quite some time afterwards), I find it an interesting read

    Why did the Universe start off with Hydrogen, Helium, and not much else? Starts With A Bang
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  5. #155
    Leipziger Leipziger is offline

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    Very interesting but I always assumed inflation was almost universally a given. At least it was a pretty dominant theory.
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  6. #156
    JamieD JamieD is offline

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    "Assistant Professor Chao-Lin Kuo surprises Professor Andrei Linde with evidence that supports cosmic inflation theory. The discovery, made by Kuo and his colleagues at the BICEP2 experiment, represents the first images of gravitational waves, or ripples in space-time. These waves have been described as the "first tremors of the Big Bang.""

    Stanford Professor Andrei Linde celebrates physics breakthrough - YouTube

    The expression on his face when he says "it's 5 sigma" is incredible! (5-sigma mroe or less means that there's about a 1 in 2,000,000 chance of the result being caused by chance).
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  7. #157
    captain obvious captain obvious is offline

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    Quote Originally Posted by Leipziger View Post
    Very interesting but I always assumed inflation was almost universally a given. At least it was a pretty dominant theory.
    AFAIK inflation was a 'hack' that they had to employ in order to account for the uniform distribution of matter that we see in the universe. Without it the big-bang would fail a fairly fundamental observation. That they have independent evidence of the inflationary period in the form of gravitational waves (a pretty amazing observation in its own right and one of the last outstanding predictions of general relativity) makes it stack up better as a theory.
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  8. #158
    owedtojoy owedtojoy is offline
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    Quote Originally Posted by Al Gebra View Post
    One thing that is worth mention is that it is further confirmation (as if it were needed!) of the absolute genius of Einstein. He pulled this out if the air in 1916 and nearly a hundred years later and assuming this discovery is what it is believed to be it certainly looks like he was right....again.
    Einstein was quite a genius of a physicist, possibly the greatest ever, but the extension of General Relativity into Cosmology was done mostly by others, and some of the work Einstein did in that area was wrong.

    For example, he rejected his own early idea of a cosmological constant counteracting gravity, but now astrophysicists think he was right all along (in the theory of "dark energy"). Einstein's 'Biggest Blunder' Turns Out to Be Right | Space.com

    He also dabbled with the idea of a Steady State Universe like Fred Hoyle's in an unpublished paper, recently discovered by the Irish physicist Cormac O'Raifeartaigh. Einstein

    Though, AFAIK, he never offered Hoyle any support when the Big Bang vs Steady State controversy was going on in the 1950s.

    To be fair, Einstein did so much of his work on the edge that it is not surprising that he could not be right all the time.
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  9. #159
    tonic tonic is offline

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    Quote Originally Posted by blokesbloke View Post
    But I've known inflation was a reality since I was a nioper and the price of the Beano and KitKats kept going up, even as my pocket money remained static!
    So, you were a Beano man? Explains a lot.

    My understanding is any scientist worth spit read the Hotspur as comic of choice, I was a Victor man myself.
    You say that to young people now and they look at you as if you were a nut, but I believe that alone explains why any true scientific discovery has ground to a halt these 20 years or more, it's all just engineering now.

    I would further like to point out that FF were in favour of retention of the comic market since God was a boy and that was before any big bang.


    As for KitKats, what kind of a wimp were you at all?
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  10. #160
    DuineEile DuineEile is offline

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    Quote Originally Posted by Catalpast View Post
    Which direction in the skies do we look to see where exactly the Big Bang started?
    everywhere. THe big bang didn't expand into space. It is the space.


    D
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