Universe
Big Bang
According to today's idea, which is based on a number of precise measurings, mainly by measuring relict (residual) radiation, which apart from small fluctuations (deviations) evenly fills the entire universe, the universe was created 13.8 billion years ago by the big bang. Before the big bang there was nothing. There was no time, no space, and all that today’s universe containes was compressed into an unimaginabely small perhaps nucleus or singularity – a place without dimensions. At the time of 10 na minus 43 seconds - (this is the so-called Planck's time, the shortest time interval - time quantum) - time started to unfold and with it space began to expand. From this moment on, space-time is constantly expanding. Space objects, galaxies and quasars are moving away from each other and the universe is getting older. The Big Bang is generally understood as a huge superexplosion. In fact, it is a series of phase transitions, jumps, which are happening in extremely small time intervals. (A phase transition or jump is for example a change in a state of matter where liquid water turns into ice). Elementary particles, from which all the matter of our universe is composed, were created before the Planck time interval. They communicate with each other continuously through so-called interactions. Interactions are very important for events in the universe. They transmit the basic exchange of informations among matter particles, keep the universe in balance and do not allow it to deviate from the set constants and rules. Without their influence everything would fall apart. A number of different phase transitions were developed beyond Planck's time. Within them, in very short intervals at high temperatures and strong radiation, various particles appaered and disappeared. In the early universe the ratio between amout of particles and antiparticles was slightly impaired. For one billion antiparticles, there was one billion normal particles, plus one more normal particle. If it was not like that, all the pairs - particles - antiparticles - would react with each other, annihilate, and the universe would be filled only with nonmaterial radiation. Without this tiny distortion of symmetry, there would be no stars, galaxies, but neither us humans. Another important moment in the evolution of the universe occurred between 10 na minus 35 and 10 na minus 33 seconds when there was so-called inflation, during which the universe was literally inflated up to 10 to the 30th power. Since then its expansion is regular.
After the Big Bang
Due to a high temperature and a huge intensity of penetrating gamma radiation, the universe is non-transparent for a long time. Only 300 000 years after the big bang the temperature and radiation pressure drop enough that the space becomes transparent. Particles, protons, neutrons and electrons, which until then had turbulent but lonely life, are starting to unite and form simple atoms - hydrogen, helium, lithium - atoms combine into molecules and in the universe matter is born for future stars. The whole space is immersed in the residual, relict radiation that remains and cools together with the universe to this day /now has around two degrees Kelvin and carries precious information about the early cosmic environment/. In further development of the universe, stars are created and perished. While dying they enrich the environment with always heavier elements, they later become part of the interstellar gas and then the stars of future generations. The stars are merging into cosmic islands – galaxies, in which they are no longer alone but are shining among gaseous nebulae, the remains of supernova explosions and clouds of thin matter. The universe is growing.
Way to the Matter
In the chapter about the universe is outlined the importance of interaction as the headstone of all events around the matter. What we know about that today will be the content of the following, a little more professional information. First a few words about elementary particles. The stable matter of the Universe is created from only three particles: a proton, a neutron and an electron. All others are unstable and decay quickly. A proton and neutron, the particles of atom‘s nucleus, are composed of even smaller, the most basic elements of the matter, quarks. Quarks are confined to a proton and neutron, they cannot exist separately. Their name physicists borrowed from James Joyce. He writes about them in his book "Finnegans Wake" and they mean something like nonsense. On the contrary, the third, stable particle, an electron, is not composed of anything, it is independent and free. Although quarks are two three-membered families with a little crazy names, for protons and neutrons are enough quarks named U = up, and D = down. A proton is composed of two U quarks and one D, a neutron has two D quarks and one U. These two composite particles belong to hadrons. And the free particles, electrons, cirling around the nucleus are leptons. All objects in the universe are built from UP, DOWN quarks and electrons. They are electrically neutral. A proton carries a positive charge and an electron a negative charge of the same value. Immediately after the big bang together with protons, neutrons and electrons, were born basic forces, by which elementary particles influence each other - interactions. They are innate to every particle, they connect all things and no particle is isolated from the influence of other particles. We know four basic forces: electromagnetic, strong nuclear, weak nuclear and gravitational. And to make it more complicated, the transfer of information requires particles that make it happen - carriers of interactions. They are generated by a field, which source is in every particle. A strong interaction is performed by a gluon, weak by light bosons W and Z, electromagnetic by a photon and gravitational by a graviton. They vary in intensity and reach. In the first moment after the big bang all the interactions were connected, but soon they separated from each other. The first was the gravitational interaction, the weakest of all. It escaped to form the expanding universe. Over long distances it has a tremendous power. It is the architect of the Cosmos, the co-creator of its beginning and will be essential for its end. An electromagnetic interaction provides non-material and the fastest particle in the Universe a photon, to ensure chemical reactions in harmony with the interaction, proper functioning of TV screens, mobile phones, computers and all sorts of junk. A photon is a very important particle, we will get back to it. A weak nuclear interaction, together with the W and Z bosons, is responsible for numerous subtle, short-distance reactions, for example radioactive beta decay... And a strong nuclear interaction using gluons holds together by a tremendous force whole atoms, and thus all the matter in the universe. So through four interactions, the universe communicates with its elementary components. Tiny particles hanging in a vast space listen, react, cooperate willingly, take care of everything material in the universe, and never fight. Let us add that all particles gained their weight by so-called Higgs bosons, which were present at their origin. We will return shortly to the particle we mentioned regarding to the interactions. It is a photon, has zero weight, moves at the highest possible speed in the universe – 300 000 kilometers per second, and behaves as a particle and a wave with defined frequencies. It is the basic quantum of electromagnetic radiation, into which we are immersed with everything around us. Different characteristics of electromagnetic radiation are represented by its wave spectrum, where frequencies - wavelengths - are arranged from the longest to the shortest: long radio waves, short radio waves, microwaves, heat radiation, light from red through orange, yellow, green, blue and purple, up to for men dangerous ultraviolet, X-ray and gamma radiation. We perceive the world thanks to the light. Despite the immense speed at which the light travels through space, it takes it eight minutes to reach the Earth from the Sun. The stars on the sky are tens, hundreds and thousands of light years away. The light from galaxies arrives to us after millions of light years, and from the farthest object, which the biggest telescopes can see, the light was twelve billion-year-old. A light is inseparable part of the life, we long for it, we dream about it, all we see is the light of the world into which we were born and in which we can with a light in our soul live.
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Illustrations: Akad. mal. Jitka Bílá
