Wolfgang Korsus Dipl.- Ing. NT , Astrophysicist
25451 Quickborn (Germany)
Email : firstname.lastname@example.org
Now the Explosion without a bang – The Big Bang theory –
All theories have been thrown into the life, by somebody of course; also this one. It was written in 1929 and it was founded, by Georges Lemaître; only what the bang in this word should be, that I cannot imagine !
He had studied mathematics and physics at the University of Leuven in Belgium and also at the same time the instruction for the Catholic parish office received. So…So
Who knows my attitude to religion and the faith tacked on there, knows how I think about it !
This person was successful in both camps; for he received a doctorate in mathematics in 1920 and was ordained a priest in 1923. A strange combination for me…..!? So the following came out thereby : because 4 years later in the year 1926 he confirmed purely independently again the correctness of Friedmann’s „expanding“ solution and used this also to explain the fantastic observations of Hubble; thus he meant that our visible universe expands continuously. If we look back briefly, we think, one comes across therefore sometime very dense, hot, energy-rich primeval matter, from which then our world has probably originated.
From this we can conclude, therefore there must have been a beginning, a „big bang“ and to the catholic priest Lemaître such a form of the Genesis appeared naturally as very natural, but it is damn far away from the dogma which was presented by Giordano Bruno or Galileo Galilei. Einstein, on the other hand, who did not want to wrap everything in dry cloths immediately, was apparently not so enthusiastic about Lemaître’s results; he was said to have written him something that read : „Your calculations are correct, but your physics is atrocious.“
But how something new runs so and then even still a clergyman is there……..the „big bang theory“ took its course, in the following years it found more and more support and supporters. But a crucial step still followed, it took place in 1964. It was once again a discovery, namely that of two American astronomers. Arno Penzias and Robert Wilson discovered something that today is called cosmic background radiation. It is a radiation that is found everywhere in the universe, measurable in all areas of the sky and it is a direct remnant of the „Big Bang“.
I’ll go into a little more detail about this discovery. It is also called one of the luckiest coincidences in the development of our world view.
So go….! The following can be read many times in the technical literature :
Penzias and Wilson worked on behalf of the Bell Telephone Company to find practicable methods of microwave communication by reflecting signals to balloon satellites at high altitudes. It was extremely important to eliminate all interfering effects with the highest precision. Even the signal receivers were cooled down to a few degrees Kelvin, just above absolute zero, so they wanted to eliminate possible thermal interference. But when they had eliminated all conceivable sources of interference, even the usual pigeon droppings on the receiving antennas, they still received a mysterious radiation of about three degrees Kelvin. This radiation was there day and night, and even at all points of the compass it was detected. Turning to friends, they then heard that at nearby Princeton University Robert Dicke and associates were finishing a paper on a „background radiation“ generated and then left behind by the Big Bang. As a result, Penzias and Wilson contacted the Princeton group, discussed their observations with them, and concluded that they had indeed found this „big bang flash.“ Subsequently, their work was published in 1965 with the prediction that radiation emitted from the Big Bang should be and is still measurable today.
So I say quite simply, do not pay attention only to the light of the stars. The big bang, of course, could not „bang“, it could emit something like lightning, that is, light, and this light is still present today in the form of the cosmic background radiation discovered by Penzias and Wilson. When I say the light is still present today, I must add : but not for our eyes. It is a microwave radiation
For info, Wikipedia writes :
The background radiation, more exactly cosmic microwave background radiation, in English: cosmic microwave background (CMB), because of her low temperature or energy density also three Kelvin radiation called, is a nearly isotropic radiation in the microwave range filling the whole universe.
Now the time has come to me to the topic „prime matter“. From what it consisted in the beginning – from the interacting particles and this has of course something to do with „beginning“. So simply expressed a plasma consisting of QUARKS,ELECTRONES and ……more.
Quoted plasma expanded rapidly and cooled down incidentally also rapidly; the quarks formed together to protons and neutrons. Eventually, these in turn fused to form nuclei. Now it was not far that electrons and nuclei formed electrically neutral atoms.
This time I call „decoupling phase“, that was about 300,000 years after the Big Bang, there the photons were left to their fate: Because there were no more unbound charged particles, and among themselves, yes, there was no interaction possible.
I use the eyes of the photons and say something to their view. The universe had become now completely transparent, the light spread out unhindered into the expanding space and these photons are simply expressed the most original signals of the big bang which we can receive.
Still to add is from my point of view, before the decoupling the plasma of charged particles was impermeable for light; we can receive therefore no signals from this time. I say the time of the decoupling, when electrically neutral atoms were formed, is therefore an absolute time horizon for us.
Attention TIME horizon I said….we are back !!!
The photons became free then, because it was the „decoupling time“ and they formed a gas that had a temperature of about 3000 degrees Kelvin. Let’s look at the wavelength, it is in the yellow part of the visible spectrum. What says, the sky was not dark at that time but shining yellow. Only since that time the universe has expanded more and more, today we can say it was so about a factor 1000, since the decoupling time. What acts then on the expansion ? It is the energy density, because this became smaller and smaller, this led again to a corresponding cooling. Therefore the cosmic radiation has now only a temperature of about three degrees Kelvin. Further with the wavelength, it increased to the value of today. This value is in the range of about 7 cm and is therefore in the microwave range. Thus, unfortunately, far below the visibility limit.
One can say quite loosely: the sky appears dark to us only because we cannot see its shining. A still to be invented glasses would make it possible that the sky shines also at night and the statement goes on, not because of the many stars, but by the afterglow of the big bang.
But remember, that should have been not yet everything, it goes on………
The mentioned glow creates a problem which is heavy in weight and which is possibly detrimental.
With it not enough, because this shining creates actually again a serious problem, ……..for our world view. Because briefly mentioned, the background radiation, which we receive today, comes strangely from celestial regions, which had absolutely no causal connection at the decoupling time, it were simply said, celestial regions, which came at the decoupling time from separate space-time areas, between which no communication was possible. Strangely enough, I had said before and rightly, because the decoupling lies very far back and since then the space has really proved, immensely extended. What this means can be shown also easily schematically.
Look at two marker points which lie one kilometer apart. An observer, who is away from each of the two around one kilometer, under an angle of 60 degrees (see picture ) For an observer distant five kilometers, however, the viewing angle amounts to only something more than ten degrees ?
Something similar also happened at the decoupling. Because at the time in question, that were 300,000 years after the big bang, only such areas could communicate with each other which were separated from each other by not more than 300,000 light years.
The angle of observation decreases with increasing distance
The temporal evolution of the cosmic background radiation
Please consider the following, it facilitates a better understanding. I say the next one: imagine that these areas are more than 1000 light-years away from us today, then their angle forms only the fraction of a degree for us. More exactly, we measure first the background radiation in a certain angle and afterwards in another angle, then that says, the origin areas of the radiations have had no connection from these two measurements. But then why do they both show the same temperature? The radiation we measure here comes from millions of regions of space that have never had a chance to coordinate. An amusing comparison is very similar: The whole thing is like a huge choir of singers but without a choirmaster but with many, many singers who cannot communicate with each other in any way. Nevertheless, they all sing the same text and the same melody. However the decoupling of „photons and matter“ has taken place at different times in different areas and these areas have produced different temperatures of their background radiation. But all behave in such a way, as if an almighty, imaginary choirmaster has lowered his arms at some time and has given the instruction: …Decouple now.
This effect, the horizon problem is also called one of the great riddles of today’s cosmology, for which, despite some interesting proposals, there is no all-round satisfactory solution so far. I will come back to one of these proposals.
The temporal evolution of the cosmic background radiation
But let’s have a look at the topic „cooling“ next .Because by this the radiation of that time has sunk from 3000 degrees to the today’s three degrees. By the way, the frequency of the light emitted by a heat source decreases with the temperature. A normal interaction of the light with the atoms of the source. This is because the atoms of the source are in different states of excitation, absorbing and emitting photons as they pass from one state to another. But if you cool the source, the atoms absorb more high-frequency photons and emit more low-frequency photons – which in turn leads to a general shift towards lower frequencies, i.e. lower temperature.
The universe has soooo much empty space, but thoughtfully with soooo few atoms, now my tentative question : How can there be a cosmic red shift there ? So if I get my thinking apparatus going so longer, then I come very close to the Doppler shift. I make therefore times the following statement. This origin of the cosmic cooling resembles a little bit the Doppler shift which I have already observed with moving sources.
There one observes that the waves were „compressed“ when they approached us and „stretched“ when they moved away from us. ……..and something like that also happens to a solitary wave as it flies through expanding space. The distance between two adjacent „wave-mountains“ increases, so the wavelength becomes longer the more space expands. If the space has expanded since the emission of the light by a factor thousand, then also the wavelength has become larger by this factor, attention, the frequency, however, has become smaller. But this kind of cosmic red shift does not mean accordingly that the source moves locally away from us, no, but only that the space crossed by it expands.
Let us move again directly to Hubble’s law…..
……v = H 0 d , it says : the velocity v of a distant galaxy is proportional to the distance d from Earth. The critical scale here is the „Hubble constant“ H 0 ; the present value is about 22 km/s per million light years. Thus, a galaxy one million light-years away from us is disappearing at 22 km/s due to space expansion, while a galaxy two million light-years away is doing so at 44 km/s.
With a constant expansion acceleration, the Hubble constant determines the age of the universe.
thus determines the age of the universe, t 0 = 1/H 0 ; thus, with the given value of H 0, one obtains the known 13.8 billion years .
The obtained expansion acceleration and its time dependence are determined by a multiplicity of aspects, both measured quantities and theoretical considerations. An essential quantity is the total mass of the universe. If this is sufficiently large, gravity can stop the expansion in the long run and ensure that everything contracts again. The result says then : an evolution from the big bang leads to the big collapse. The other way around would be the following, if the mass of the universe is small enough, the expansion overpowers the gravity, and the acceleration increases with the time.
I have just considered or explained two possibilities; a critical boundary between these two possibilities results, a constant acceleration has been preferred. The nature of the universe likes it so. Only the mass of the universe is not easy to determine, however, because there is the visible content and still large quantities of dark matter , this is invisible and which can be determined without exception only by its effects on the gravity behavior of galaxies. But in addition then still the already mentioned dark energy comes, it penetrates the entire universe also brakes it the gravity and consequently the expansion of the universe may cause. The newest realizations were distinguished with the Nobel prize 2011, they point to an increasing acceleration and underline the importance of the not mysterious dark energy. In any case, to conclude, the approximately 14 billion years today remains the best value for the age of our universe.
But before that I would like to return to the question, how the expansion actually happened very shortly after the big bang; this brings me also back to the mentioned cosmological „horizon problem“. However, I point out more strongly that the „reason“, the actual trigger of the Big Bang, is not known. But one has very well a quite impressive possibility or better the attempt to describe the development of the earliest stage, namely one………es follows the next part with the still following resolutionl