In the beginning was the soup of particles
How were the stars born? What will happen to them? What is the universe made of? What are we? «A mixture of nothing» was the answer given by academic Dimitris Nanopoulos, in an interview with Kathimerini on the occasion of his talk at the Academy of Athens yesterday, where he displayed new data on the genesis and evolution of the universe. The universe was a fortuitous event, and we were pretty accidental ourselves, said the scientist, holder of the Mitchell/Heep Chair of High-Energy Physics and distinguished physics professor at the Texas A&M University. «It will not die in flames, nor from old age, as predicted by some astronomers. The universe will continue to exist into eternity and expand continuously,» he said. «This is something that has been known for years but has now been demonstrated experimentally. Since February 13, when the experimental data were evaluated that had been collated by a NASA space vehicle, loaded with high-precision instruments, scientists now speak of the age, composition and future of the universe with some degree of certainty.» For Nanopoulos, the findings are the most significant discovery «of the last 50 years.» Going back in time The instruments were able to go back in time and capture the universe in its infancy, when matter had not yet been formed, or, more accurately, exactly at the moment when matter was in the process of being formed. They «narrated,» said Nanopoulos, the story of the universe’s birth, when a primordial subatom exploded. From this explosion came space, time and matter. The instruments told us what the universe was made of, and that we form an infinitesimal part of it. And they told us the universe was flat. That is, they confirmed what scientists had believed for years about the genesis of the cosmos. What is the importance of the new experimental data? It’s huge. In the last 15 years, cosmology, the science which studies the appearance and evolution of the universe, has embarked upon its golden age. And the Parthenon of this era are the experimental data that have been gathered recently, since February 13, by a NASA satellite by the name of WMAP (Wilkinson Microwave Anisotropy Probe). But let’s start at the beginning. For the last 70 years, we have known that we live in an expanding universe. The best-known and most convincing theory of the birth of the universe is the big bang theory. At some moment, 13.7 billion years ago (we know exactly when, after the NASA experiments), there was a huge explosion and since then the universe has been expanding. The expansion of the universe and the finiteness of the speed of light are divine gifts from nature to enable us to study her. When we look at the sun, we don’t see it as it is at that particular moment but as it was eight minutes ago. Light takes time to get somewhere. So if, using powerful telescopes, we look at heavenly bodies that are emitting light rays in the depths of space, it is like looking into the depths of time. Over the past few months, we have had images of the universe 380,000 years after its appearance – very near its beginning, that is, and at a crucial juncture in its evolution. Until that moment, energy and matter were a kind of undifferentiated soup (of particles). Afterward, they began to separate and the first atoms appeared which formed hydrogen, helium and other elements. A chance event How were the stars formed? This is explained by a theory that was first formulated 20 years ago, but which has recently been fully confirmed by the NASA experiments. It is the inflation theory, which tells us that the universe, a trillion-trillion-trillionth of a second after the big bang, experienced a sudden, tremendous expansion (think of an ordinary balloon suddenly expanding to the size of Greece). Then the symmetry of forces was broken, some anomalies appeared. One of these is us. In what way? For the universe to develop structures and for it not to be a homogeneous soup, there must be fluctuations. If the universe were the same everywhere, then nothing would have emerged. So somewhere, quite by chance (according to quantum physics), due to differences in the density of matter, there was a slight fluctuation in energy. If I put a mass in a space, it will attract more mass due to gravity, creating a body that will grow. That’s how the stars were formed – by chance. The universe appeared by accident, the first stars and galaxies appeared by accident. Our sun is an ordinary star and the Earth a rock that was caught up in an orbit around it due to Newton’s law of gravity… We have known this for the past 50 years. However, now, we’ve confirmed it. The «snapshot» of the universe at 380,000 years old, at the crucial juncture, is for us a tremendous «We knew it»… What is the future of the universe? It will expand for ever. It is an open, flat universe. It does not have two dimensions but follows Euclid’s laws of geometry, the simplest form of expansion. It could have been a sphere, but it is like an expanding cube. There isn’t a curve anywhere within it. There are three theories about the expansion of the universe: the closed universe (it expands until it stops somewhere and then starts to contract); the open universe, which is in a perpetual state of expansion and is curved; and the open universe, which expands infinitely, but is not curved. Nature chose the simplest course. I call it universal nihilism, because in the flat universe in which we live, the total sum of energy is nil. There is positive and negative energy. The sum total is zero. It is a very satisfying philosophical reply. The universe began from nothing, which has by definition zero energy; it acquired form but continues to have zero energy. In other words, we are a mixture of nothing. Yes, but the universe is made of matter. What is this matter? The atoms and molecules of which we are made constitute precisely 4 percent of the universe. Twenty-three percent is dark matter and 73 percent is dark energy. That really completes the Copernican revolution. Not only are we not the center of the universe, but we are not even made of its basic matter. As for dark matter (we call it dark because it emits no light), my team formulated the prevailing theory, which describes neutralinos, the particles that compose dark matter. But there is no theory that explains dark energy. What about black holes? A black hole is created when a star ceases to emit light. The sun is composed of burning protons and electrons. It is a large nuclear reactor. But it does not have infinite mass. Our sun has been around for 4.6 billion years and will be around for another so many years. It will shrink considerably, and become what we call a dwarf and then turn into a neutron star or a black hole. But when a star collapses to that extent, the compaction of mass is tremendous, as is the gravity field it creates. So anything that passes near it is sucked in and vanishes. So, we know the fate of our solar system. We have 4.6 billion years of life left. We have much less. We will destroy the earth ourselves much sooner. This planet is doomed. We can see that. It is threatened by nuclear or environmental destruction. As for human beings, a change of residence would be a further step in their evolution, because anyone of any intelligence will hop aboard a spaceship and leave. The Taleban of the West and East will remain.
