Growth
Expansion of Our Universe (or is it?)
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The universe that we see is thought to be 'expanding' and that objects further away are apparently travelling away from us at a faster speed than nearer objects (hence red shift phenomena). The simple explanation for the expansion of space is because space is constantly being 'created' by quantum fluctuations which acts just like compound interest. For example, if it is adding 10% every time unit, then after the one time unit, it expands to 110% but after the next time unit it expands to 121% (i.e. 110 plus 10% of 110%). Hence the expansion is accelerating. Remember - space AND matter are constantly being created by quantum fluctuations, it isn't matter that is moving away through an infinite vacuum but new 'space' that is 'carrying' it!
Another explanation of expansion is that this is what it 'appears' to be doing but, although these movements are relatively true, the 'outward' movement is not logical with the recent observed discoveries.
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The edge of the universe is actually the so-called 'Big Bang'? Which came from a single point (a singularity?).
So how can that be expanding? What is it expanding into? Surely not an infinite 'space' because we have just established it must be the so-called 'Big Bang'? 'Space' has actually been shown to be vacuum energy due to quantum fluctuations, so the expansion must be from the the furthest point towards us.
We live in newly created 'space'. Although you have to be aware that it is at this point in time we are living and this speck of time is only a minute part of the lifetime of the universe.
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Einstein was not comfortable with the notion of an infinite Universe that contained a finite amount of matter. He believed that a spatially bounded, and thus finite, Universe was a much more natural choice from the point of view of general relativity. It was also the simplest choice and the most mathematically elegant one. The geometry of the Universe is uniquely determined by its total mass (and/or its energy, as a consequence of special relativity, described by Einstein’s earlier theory). Remember that we are looking here for simplifications. Einstein’s first simplification became known as the cosmological principle. It told us that the Universe on average looks the same everywhere in all directions. Much to Einstein’s disappointment, this theory came with a high price tag. If the Universe is finite and static, and gravity is an attractive force, matter will tend to collapse on itself unless it has negative pressure, which is a weird property BUT Einstein was not aware of dark energy and the creation of space and matter by quantum fluctuations causing an accelerating expansion which is still finite yet does not require a negative pressure to prevent collapse.
Also, a logical conclusion is that the universe cannot be EXpanding but 'INspanding', within a singularity. In Einstein's relativity theories, travelling inwards at the speed of light dilates time and space to zero, in fact the conditions of a singularity. If all objects are inspanding at the speed of light, this suggests that the singularity and our 'normal' dimensions can coexist and relative speeds of neighbouring objects traveling at less than the speed of light can also exist. Local relative objects will be travelling at similar relative speeds to us which gives us the local relatively slower speeds but, on average, all local objects are travelling at the speed of light relative to the 'beginning'. Our current position in time will always be equidistant from the 'birth' but inspansion within a singularity means that we can only see the start point as a spherical surface. The diagram below shows the beginning 'big bang' at the outer spherical surface edge of our universe but that does not make sense, especially if we ask what is beyond that start point?
Hence, from our viewpoint, the slowest expansion is local and the fastest accelerating expansion furthest away; an observation made only over recent years. These observations remove the need to create ideas of external attraction forces, negative pressures or misunderstood dark energy affecting gravity and explain the distant acceleration effect. As explained previously, the sudden 'inflation' due to time being applied to the source quantum energy (i.e. dark energy) would give an effect of a 'big bang' whether inwardly or outwardly (from our viewpoint). If we are travelling relatively away from the 'birth' at the speed of light, then time and space are relatively zero and are consistent to being part of a singularity. Whether Einstein's relativity holds for the early universe formation remains to be confirmed but, as I have shown, the speed of light depends on the 'space' and 'mass' of the universe (both formed by quantum fluctuations, see Genetics section) which means it would initially be zero which would still be true for a singularity.
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Hubble view of our Universe
CMB Polarization and Inflation
A key motivation for polarization measurements is the theory of inflation, which suggests that the size of the universe expanded by an unimaginably large factor during a tiny fraction of a second at the time of the Big Bang. This theory has been quite successful in explaining many observed features of our universe, including the origin of the CMB temperature anisotropies (i.e. small variations in temperature change).
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One as-yet-unobserved prediction of inflation is that it might produce a background of gravitational waves but it has been determined that this may not be the case now (see bold comments below).
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For a simple geometric explanation of E and B modes, see the diagram below. For both the E mode (left) and B mode (right), the polarization (indicated by the headless lines) varies along the horizontal direction indicated by the wave vector, k. For the case of a pure E mode, the polarization is parallel or perpendicular to k (i.e. horizontal or vertical). For a pure B mode, the polarization is rotated by 45° with respect to k.
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The search for B modes, maps of the sky polarization were made showing how separate the E- and B-mode contributions for all possible wave vectors (the image below shows the B-mode part of the BICEP2 map). In March 2014, a discovery of just such a signal with BICEP2, but subsequent results from the Planck satellite have shown that Galactic foregrounds (specifically dust) accounts for most, or perhaps all, of the B-modes. The joint analysis with Planck was published in February 2015. Past instruments have strived to achieve the sensitivity to detect degree-scale B-modes, but now we face the challenge of characterizing them in detail to determine whether they originate in the early universe or else more locally.
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Shown here are the actual B-mode polarization patterns provided by the BICEP2 Telescope.
Image Credit: Harvard-Smithsonian Center for Astrophysics
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A sufficiently sensitive radio telescope shows a faint background noise, or glow, almost isotropic (same in all directions), that is not associated with any star, galaxy, or other object. The white noise on older analogue TVs also showed the CMB background noise, if you remember that far back in time.
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A problem is that B-mode polarization can also be caused by other effects, such as gravitational lensing and interstellar dust. In 2014 BICEP2 announced they had discovered B-mode evidence of cosmic inflation, but then had to walk back their claims to be more tentative. The upshot of BICEP2 was that the results were inconclusive. But new results from the BICEP Collaboration have been released, and it is a bit more encouraging. See site referenced.
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New work uses data from the latest BICEP observation run known as BICEP3, as well as observations from Planck, WMAP, Keck, and BICEP2. The combined data reduces noise levels to a point below the signal levels of some inflationary models. At this level, they found no B-mode polarization that could not be explained by dust or other effects. In other words, they saw no evidence of primordial gravitational waves. This means a broad range of so-called “simple” models of early cosmic inflation can be ruled out. If early cosmic inflation does exist, its effect must be more subtle than we thought.
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Observed polarization modes for BICEP3. Credit: BICEP/Keck Collaboration
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