Hannes Alfvén (1979) - Observations and Cosmology

I wish to thank you very much for your kind introduction. It is a, a great pleasure to be here and to listen to so many interesting lectures. And especially I am glad to note that there are so many physicists who invade other fields of science. We have just heard today a couple of excellent lectures about biology. And the physicists have made or presented all sorts of excuses for going there. I think that they do not need any excuse for this, but I should like to try to follow the same approach, namely to try to go into a field where I am an outsider and this means that I would like to present the views of a plasma physicist on cosmology and astrophysical problems in general. As an excuse for doing so, I should perhaps mention that everybody, everybody knows that 99.9999999% of the universe consists of a magnetized plasma and therefore it may be allowed for a plasma physicist to present his views there. And the.., we have listened to wonderful lectures about cosmology and it has been stated here the general agreed fact that the Big Bang cosmology is the cosmology, which explains everything. And I am of course very impressed by this cosmology. It is based on the General Theory of Relativity and in the year when the hundredth anniversary of Einstein is celebrated, I need not, I need not stress to you how wonderful, how beautiful the general theory of the general relativity is and when you listen to the presentation of Professor Dirac on his version of the general ..of the Big Bang theory, you are also very impressed, of course. The general feeling is that it is a beautiful theory which explains the whole evolution of the universe, from the Big Bang, the “Urknall”, when all matter was, we have now, was concentrated in one point, in one singular point. There are of course a number of, of difficulties which is, it is a little, which there are a number of things, it is a little difficult to understand, namely that the whole world which we see, Lindau and Bodensee (Lake Constance) and the whole Earth and the planets and the Sun and the galaxy and all that once was once condensed into a very small volume, as small as this, or as small as this, or even still smaller, because a singular point is very, very small. And, but I take the authority of Einstein and Professor Dirac that it must have been so and furthermore, you hear the detailed description of what happened during the first three minutes after the Big Bang and that is described, as you know, in detail. You are a little surprised to find that the accurate dating of this is not so well known. Professor Dirac said that some people say that it was 10 billion years ago and other 18 billion years ago and I think this states, this states the general situation, there is large uncertainties in certain respects, but of course not about what happened during the first three minutes. But with this and then of course you ask yourself, what happened before these three minutes? And then I haven't got any answer yet what happened before, well this has no meaning because nothing existed there, and how did all this come into, into being? There are some people who say that this proves the existence of God, because it was must have been God who created all this at a certain moment and this means that we mix science and theology, we come into the borderline there and this is a thing which perhaps is somewhat dangerous. But as I said, the most, the strongest impression is the wonderful beauty of the whole theory. It explains everything. However, beauty, beauty is sometimes dangerous, also in science and especially in cosmology. If we look at the history of science, there has been other cosmologies which have been wonderfully beautiful. Take the six-day creation, wasn't that, isn't that a wonderful cosmology? It, it, and still it is, inspite of its beauty, it, it isn’t believed very much, at least not in the scientific community. And take the wonderful Ptolemean system, which was generally accepted 1000 years or so, with the harmony of the spheres and crystal spheres revolving. That was also very beautiful. But still, there are very few people who believe in it, except of course those who believe in astrology and that is perhaps more than those who believe in science, in astronomy, but that is, but these are outside, extra-muros to us, they are not, do not belong to the scientific community. But I think that the, the reason why these very beautiful cosmologies are not, are not accepted anymore is that they are not reconcilable with observations, because science is, after all, empirical, to, to some extent, empirical. We have wonderful theories, of which we have heard so much, but there is also empirical evidence and how does that agree with the, the theories in this respect? We have heard that there are convincing proofs for the Big Bang cosmology and we have heard that in some cases there is expected to be convincing proof of it in a few months, but let us see a little how we, how all this, this, how much, to what extent the observations support the Big Bang. I think that the general impression is that all really good observations support Big Bang and all bad observations contradict it. But what is the definition of a good observation? It is an observation which confirms the Big Bang and, and the definition of a bad observation, an uninteresting observation, is an observation which brings Big Bang into some difficulties. We have heard about these wonderful models. It is a homogeneous model which is the basis for the Big Bang, derived from the General Theory of Relativity. And, so the first question is, is really the universe uniform? Is it isotropic? If you go out in the night and look at the stars, you don't, you, you see something which is not at all uniform But that is only a local anomaly. It is only something that happens here in our close neighbourhood. And, if you go out and have a, if you have a look on the galaxy, our galaxy, this does not either give you an impression of a uniform distribution of matter. But, this is again a, a local anomaly. If we go out further, we should, according to the theory, to be, be able to apply a uniform homogeneous theory. That means that such islands should be distributed uniformly in space. No, it does not, because the galaxies are lumped together in, in, in groups of galaxies and these are lumped together in, in clusters of galaxies, and the clusters of galaxies are not either uniformly distributed. They are lumped together in super clusters. And that is as far as our information goes because if we go to still larger size, we don't know anything with certainty from observations of this kind. Can I have the projector, the projector on here? This is a diagram by DeVancouleurs which gives the experimental, the observational results, correlation between the maximum density and the radius of a sphere, and you see here, if you have these represent galaxies and the average density in, in them is something like 10-23, these are groups of galaxies and, and clusters of galaxies and this is the last largest unit you can measure, that is, a super, super cluster of, super clusters of galaxies, they come down here. And you see this does, this means that we have rather a hierarchy of lower and lower densities when we go out to very large regions. Here we are out on close to the 1026cm and the Hubble radius, the radius of the universe is called 1028, so we are, have here still a couple of or two orders of magnitude to go and about this region we don't know anything from galactic observations, how uniform it is. It is quite possible that, from here further out, we have a uniform density that is about 10-29, which I think is the, the figure which Professor Dirac quoted. However, if you take, you can also without being in disagreement with any observational fact, continue the extrapolation here and that brings you down to 10-34, 10-32 at this distance, which is three or four orders of magnitude below this value. So we obviously here have an amplitude about which the observations don't us tell anything. There is nothing wrong. We cannot say that the Big Bang uniform picture is wrong, but we can also, also accept such a solution and we should just, it is of interest to see what we result we can reach if we take the other alternative. So it means that the homogeneity of very large, of the universe or meta-galaxies is also always, sometimes is called being just that part of, of the galaxy, which, with of the universe we explore here. That, this uniformity is not known with any, is not proved by observations of galaxies. What is the main proof of it? Well, it is the most important phenomenon which has been discovered for the, for quite a few years in astrophysics, namely the black body radiation, which is completely isotropic. And that shows that, that. That shows that the, the universe as a whole must be completely isotropic. It agrees with the Big Bang model and this is actually the strongest support that, that ever, there is. It is, as far as I know, the only support there is for it, or perhaps I should say was, because one year ago there happened a very regrettable thing, namely that this radiation turned out not to be isotropic. It, it is quite, it is may very well be due to a local anomaly, of course. But it is, if you correct for the rotation of the galaxy, you still get a large anisotropy, of the order of a velocity of 800 or 1000 kilometres per second. And if you then correct for the motion of the, our, our galaxy in relation to other galaxies in the Virgo cluster which is the larger unit, you do not either get any, any better isotropy. So it must be some still larger unit, where this, this unit, this anisotropy is caused. So I'm not quite sure that we could rely on this either. Then comes the Hubble expansion. The Big Bang says that everything was condensed in a singular point and from that, the galaxies drew out in all directions. And there is no, this is correct with at least to the extent that there is a Hubble expansion, the galaxies move outwards. And this is a diagram which shows the relation between the distance, which is measured by corrective apparent magnitude of the galaxies and this is the velocity. And you see that these points very well on a straight line, which it should do according to the Big Bang theory. They should all be, be lying on a straight line and of course we have, we have observational errors because these measurements are very difficult to make. However, if we take the individual observations here, we have the distance and we have the velocities and from that, we could construct a diagram how these have moved under the assumption, which is very reasonable, that they haven’t changed their velocity. This is now the distance from us and this is time, and you see that if you go back in time, these are all coming closer together. Now every individual point here is used for such a straight line and they come together here. So there is no doubt that the, our meta-galaxy is expanding at present. However, is it, does this expansion necessarily derive from the Big Bang here? It's quite possible. You cannot rule that out because these could very well be observational errors. It might be that everything has derived, has originated from one point here and then it has gone out like this and the, the minimum size which you get here may very well be due to observational errors. However, we cannot say from observations it is possible to conclude this. We can conclude that, once the meta-galaxy was much smaller than now, at the Hubble time, It could be zero, it could be a singular point, but it could very well also be much larger. So this means that we, we if we try to construct an earlier state of the our meta-galaxy from observations, we could do that, that could lead to the Big Bang model, but it could also according to this lead to a rather drastically different picture. You have here the Hubble radius, the Hubble density and so, so on and here is, is beta, that is the velocity, the velocity of the different galaxies, which have been measured. And the galaxies for, for which one has measured the red shift are, most of them are well below 0.3 of the velocity of light. That means that this is the size, 3x1027, if we take the Hubble radius as 1028. Professor Dirac gave a, a model in which he said that he discussed especially the, the part of the universe which was receding with a velocity which was less than half the velocity of light, which we can take for this and here we can take 0.4 as some sort of average. This is only to show you what one may get in such a way. When you see that the total rest mass of the, the meta-galaxy is given here and the rest mass energy, rest mass multiplied by the square of the velocity of light, comes down to 483. The units is 1070 erg. You can also calculate the kinetic energy of this, and the kinetic energy comes out to be 19. It is about 5%. So the known the part of the universe, which we have observed with any degree of certainty has a kinetic energy which is about 5%, a little different here, of the, of the rest mass. So in some way, we need to have an energy put into the meta-galaxy which gives you 20% about, and this, from that we can construct, I don't have so much time, I see that goes very rapidly. This is a table of what we have here. We, what is interesting is to see, this is the minimum size of the meta-galaxy and what is interesting is that the, we are even at the minimum size, 100 times outside the Schwarzschild limit, which means that the correction for the General Relativity effect is only 1%. What does this mean? It means that if we go out to the galaxy, in the galaxy, we, we of course have measured General Relativity effects in our close neighbourhood. If we go out to study the, the behaviour of the galaxy, no one applies General Relativity. Every, every all the motions there can be used, can be calculated with classical mechanics. If we go out, further out, as soon as we are far from the general, from the Schwarzschild limit, we can use classical mechanics and use Euclidean geometry with a high degree of certainty. So actually, with this model we have a 1% correction for the General Relativity and something like 10, perhaps 25% correction for the Special Theory of Relativity. So you see that this is, this is, is a possible model, which as I said is just as well reconcilable with the observations, with the observational data as the Big Bang theory, as far as I can see. However, now comes another thing. If you, and that is, that are so many other very interesting phenomena which have been observed in the, in the, in astrophysics. And one of the most dramatic events, dramatic things is the QSOs, the quasars. And the quasars have velocities, red shifts, which are much larger than the galaxy’s. Under the assumption that the quasars, the QSOs, have a red shift which is due, which is cosmological, that is due to the Big Bang, then you can go out from a point, from 0.3 the velocity of light, 0.4, out to almost the velocity of light. You have red shifts which are up to two or three or perhaps even more. So it is a critical question whether the red shifts of the QSOs is cosmological or not. And the red shifts, the, the QSOs are a very, very interesting, very fascinating thing to study. And I have here a short summary of, of their properties. They are not really introduced very much in the general cosmological discussion, and the reason for this is simply that they are very awkward to the Big Bang cosmology. There is no evident explanation of it and you can see that they, they are causing considerable trouble. The QSOs are very large releases of energy. It is of the order of the annihilation of one solar mass per year and in some cases still more. They have red shifts which are very large and the controversial question are these red shifts, is are these red shifts cosmological or are they caused by some other, other mechanisms? And then you can see that what we should take out here is, is especially that some QSOs are located close to galaxies, and in certain cases they have the same red shift as the galaxy. But there are many cases and undoubtedly very convincing evidence that there are QSOs closely, close to galaxies, but they have very different red shifts. This is, is, has been demonstrated by my measurements by Margaret Burbidge, the Burbidges have very strong evidence for the non-cosmological red shifts and are in Pasadena, has made beautiful measurements of this. So there must be mechanisms by which these QSOs get up to close to the velocity of light without being these velocities being produced by the cosmolo..., by the Big Bang. And you can see what requirements one has here. The, if, if you have, if you take the enormous energy release, which are measured and you introduce the condition that this energy is emitted in one direction, then you can get the, the bodies up to these velocities. This is one possible suggestion to, to get, to explain the QSOs. This means that the very large velocities are not necess..., which we observe, are not necessarily cosmological. There are other mechanisms also. But what are these mechanisms? What is the mechanism which produces the energy for the QSOs? We see immediately that nuclear energy, which is giving us the ener..., the energy of the stars, is by far not sufficient. So we have three possibilities. We have either to invent a new law of physics, which gives you these very large energy releases, which we perhaps are a little hesitant to do. We have two other alternatives left. One is gravitational energy and the other is annihilation. And the gravitational energy, there have been a number of theories according to which black holes produce these large energy releases. But if you try to work out a theory of the QSOs, how they are accelerated, you find that you run into very serious difficulties. And then is just the possibility that we have annihilation as an energy source. And that brings up an interesting problem, namely is there antimatter in the universe? Is the universe symmetric with regard to matter and antimatter? This has of course been speculated much about it. And it is Oskar Klein in Stockholm who has, who made twenty years ago a systematic effort to show that, to make cosmological model with the, with anti, where a symmetry between matter and antimatter. This, there has been much objection to that and this is essentially because if matter and antimatter are mixed in the universe, you would have an enormous gamma radiation and you will have a very rapid annihilation of it all, so that this could only be a very, could, could not persist for a very long time. However, all this depends upon the assumption that you have, that the universe is, is homogeneous. We have the, that there is, can be no, that there cannot be separate, separate regions. And this is one of the really dramatic new, new results of space research, namely that the properties of space has changed in a drastic way. And I am not speaking about the four-dimensional space in the Big Bang theories, I am speaking about the space, which is explored by space craft. Fifty years ago, it was believed that everything was vacuum outside the celestial bodies. Then it was observed that there was an interstellar medium, interplanetary medium, interstellar medium, and we heard earlier a lecture about that and it is, it was then natural to assume that this was a continuous medium. And it was natural to assume that also in our close neighbourhood in the environment of the Earth, the so-called magnetosphere, and in the interstell..., interplanetary space the so-called heliosphere or solar magnetosphere, that we had a homogeneous medium. This has not, is not correct. This is one of the most, most surprising results of space research. If you have the magnetic field as a function of the radius from the Earth, this is the Earth, and you go out and measure the magnetic field by spacecraft, it should be decay as r-3, and that is just what is does, out to about 10 Earth radii or something like that. Then it suddenly changes to the opposite sign and goes on like this. And this is a most dramatic change. It is, it takes place in a region which is a few cyclotron radii. It is a sudden change in the magnetization. So the magnetization here is in that direction and it is here in that direction. The magnetization of space is not continuous, it is discontinuous, it means that we have a current layer here. And such phenomena have been found not only in the magnetic poles, it has also been found in the magneto-tail of the Earth, in the solar equatorial plane, we have an outward-directed magnetic field which suddenly changes to the opposite and again there is a thin current layer. It has been found in the Jovian, in the Jupiter's magnetosphere, and so on. There’s half a dozen places where we observe this. It means that space in our close environment has a cellular structure. There are cells with that magnetization and there are cells with that magnetization. And it is rather a water-tight separation surfaces. And this is, this means that we have, space is no longer uniform. It consists of a number of cells and they are separated by current layers and on two sides of the current layer you have different magnetizations, different pressure, different densities, and perhaps you also could have different matters, different kinds of matter. Such thin layers, I will just show you here what it is. This is the interplanetary medium, this is the Earth, the Earth’s had a magnetic field like that, that is 50 years ago when space charge, when space research started, we got this picture, a neutral sheath here. Now, this is one of the later models. This is the Earth, and you’ll see a number of such layers. Space is drastically different from what it was earlier. And these interfaces cannot be detect, had, were not detected from the Earth. They cannot be detected unless a spacecraft penetrates it. Even if it comes close to it, you see no sign of it. We knew, hence, that space has this structure. How far out? As far as the spacecrafts go. And what is beyond that? No one knows. We cannot prove that it is, that it has the same cellular structure further out. It could very well be that we have a wonderful homogeneous model. But the limit is just as far as spacecrafts go. So perhaps it is easier to assume that this is a general property of space, that it always everywhere has this structure, and then (time is getting on). We can just see here a model of a layer separating matter and antimatter. We have supposed that in interplanetary space we have interstellar space, we have a region containing matter and another region containing antimatter. And then there will be a boundary layer where they keep in contact and they produce high-energy particles here. And you can calc..., you can see that these, the, the number of such particles which are produced is very small. You can, you have no hope of detecting it from any, any difference, any distance, and the distance which such a Leidenfrost layer occupies need only to be a 100th or a 1000ths or a 10,000ths of a light year. So we can very, very well assume that the cellular, if we, if we accept a cellular structure, we can very well think the universe divided in such regions. And this is important because it is obvious that it has cosmological consequences, quite a few of them, which I shouldn't go into more here. I should only like to say that it seems that with this, with the idea of a symmetric universe, you can explain quite a few of the, of the observations, which are embarrassing to the astrophysics and especially to cosmology, namely the enormous release of energy in the, in the QSOs, the so-called gamma ray bursts, quite a lot of the x-ray radiation and so on, but this will be, be take us too far. I thank you.

Hannes Alfvén (1979)

Observations and Cosmology

Hannes Alfvén (1979)

Observations and Cosmology

Comment

When Hannes Alfvén gave his talk at Lindau, he was well known by the general public in Sweden as the eminent scientist and Nobel Laureate who was strongly opposed to nuclear power for environmental reasons. Among his scientific colleagues world-wide, he was at the same time known to be a strong opponent of the prevailing theory of the birth of the Universe, the Big Bang theory. In Lindau he spoke to an audience of students, young researchers and Nobel Laureates, most of whom probably whole-heartedly accepted the Big Bang theory. Alfvén had been active as a political speaker in Sweden for some years and it is interesting to hear him use an old rhetorical technique to try to make his point. He several times first gives praise to the “beautiful theory” or “wonderful model” and then almost immediately brings up his criticism: “What happened before?”, “But the Universe is not homogeneous”, etc. So does Alfvén have an alternative theory? Since the 1960’s he had been working on a model of the Universe originally put forward by Oskar Klein, professor of theoretical physics at Stockholm University. In this model the Universe contains equal amounts of matter and antimatter, so that some stars that we see are made of matter and others of antimatter. When matter meets antimatter a violent annihilation tales place and energy in the form of electromagnetic radiation is emitted (radio waves, light, X-rays, gamma-rays, etc). As a plasma physicist, Alfvén had been working on mechanisms that would keep matter and antimatter mostly separated from each other. At the end of his talk, he first brings up annihilation as a possible energy source driving the very energetic stellar objects named quasars. He then describes spacecrafts actually finding a cellular structure with cell boundaries having magnetic fields in different directions. Even if a few scientists are still working on the Klein and Alfvén model of the Universe, it is today looked upon as dated. But what will never be dated is Alfvén’s strong scientific plea never to accept “final solutions” because they are beautiful, but to always look out for new empirical evidence!

Anders Bárány

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