From Big Bang to Big Crunch - a brief journey from unimaginable subatomic world to incredibly vast universe.

Are you aware that when you breathe, each time we inhale about a billion trillion molecules and we each have molecules of Shakespeare or say Gautam Buddha (may see details in my article dated 13.4.09 on this blog). We simple can’t imagine such tiniest possible particles (that too illusionary) are all over the universe. The idea that everything is made of atoms goes back to the Greek philosopher Democritus (460 BCE –  370 BCE). Now we know, these atoms consist of positively charged nucleus in which protons and neutrons are bound together by strong nuclear force and are balanced by negatively charged electrons surrounding them. Typically, atom is about 100,000 times bigger than the nucleus at its center. A proton in an atomic nucleus is about 2000 times more massive than an electron. The protons and neutrons in turn are made up of even tinier particles called quarks. Hence all matter that makes up our physical world is composed of 2 kinds of fundamental particles – quarks and electrons.

We further know for sure that these elementary particles are nothing but discrete packets of energy so constituents of everything we see in this world are in a constant state of flux. It is also a remarkable fact that 99.9999999999999 % of the volume of ordinary matter is empty space. If there were some way to squeeze the entire empty space out of the atoms in our body, humanity would indeed fit into the space occupied by a sugar cube. It is also established that mass is conjured out of empty space in the form of microscopic particles of matter. The quantum vacuum is actually a seething morass of microscopic particles such as electrons popping into existence and then vanishing again. Actually, every particle created is created alongside its antiparticle, a particle with opposite properties. So a negatively charged electron is always created with a positively charged positron (Marcus Chown in Quantum Theory Cannot Hurt You, 2006). 

Just to briefly explain further, the primary elements of reality are not individual particle but underlying fields of energy. So steel rod as we see it hard and solid is nothing but quantized “lumps of energy”. These so called un-manifest fields or quantum fields pervade all space and time. According to quantum mechanics, their influence is non local that means it is felt equally all parts of the universe. Quantum mechanics is a set of principles describing the physical reality at the atomic level of matter and the subatomic (electron, protons, and even smaller particles). These descriptions include the simultaneous wave-like and particle-like behavior of both matter and radiation (wave-particle duality). Some of its predictions and implications go against the "common sense" of how humans see a set of bodies (a system) behave. Many other characteristic features of quantum world have been explained in my earlier articles specially the one posted on   Feb14,09 on this blog.

The universe, as cosmologists and astrophysicists know for sure, began 13.7 billion years ago with a big bang. The universe is still expanding today. On a larger scale universe is uniform wherever we see but at the level of clusters of galaxies and below, visible matter is clumped together. There are more than 100 billion galaxies and in each galaxy there are over 100 billion stars like sun. Now imagine, on a clear night, only 3 to 4 thousands stars are visible to the average human eye. Many scientists say that the universe is just an infinitesimal part of a single ‘bubble’ or pocket universe, set amid an infinite assemblage of universes – a multiverse – itself embedded in inflating space that exists without end (Paul Davies in The Goldilock Enigma). Einstein’s theory of relativity predicts that the universe should have zero total mass as the positive mass-energy is exactly neutralized by the negative mass-energy of the gravitational field of all the matter in the universe.

Our observable universe is 10²³ Kms and it contains about 10⁵⁰ tonnes of visible matter in the forms of stars, gas and dust, all of which combines to create a powerful gravitational field. The volume of space within the horizon contains about 10⁸⁰ atoms and about 10⁹⁰ neutrinos and photons and each particle can carry a few bits of information only. According to a calculation done by Seth Lloyd, a theoretical physicist of MIT, the total information in universe comes to about 10¹²⁰ bits. Most of the universe is made of something that is still not identified. Ordinary matter makes up just 4%. It looks as though most of the mass of the universe is in the form of ‘dark energy’, which is gravitationally repulsive making the universe expand faster and faster. However, if this energy remains constant, the universe will ultimately collapse to a big crunch.