IN the last issue I dealt with the question, whether the Creationist theory or the Evolution theory is more credible than the other?

The two questions that remain to be probed into from the family of questions I raised in the earlier discourse on the paradox of life are: how old is life exactly? Whether life existed on Mars, and if it did, in what shape and form?

The ‘popular’ form of life known to all of us — through films, cartoons and books are not more than 225 million years old, a few million more allowed for their gradual evolution. These are dinosaurs (Latin: terrible lizards).

Dinosaurs ruled the Earth for more than 160 million years. We know them from the study of their fossils and the in-depth study of biology and that of bone structures. Surely origin of life is far older than dinosaurs.

Do you remember that I spoke about prokaryotes and eukaryotes? This needs to be defined and I will do so along with viruses. For these are the basics, or building blocks of life. All of these are multi-cellular organism. That is, they are not only much smaller than a cell (human, animal or floral), but conveniently push through a cellular wall and reside inside and influence the characteristics of the host cell. That’s how small they are.

But before we proceed further, we must understand what a cell is, particularly the role it plays in the formation, and sustenance of life (including flora).

A cell is the most fundamental, yet complete structure in itself. No life can come into being or flourish without a cell first coming into being and all forms of life are a collection of cells — that is it is multi-cellular. But what is life in the first place?

Life is not a status, but a process, or a series of chemical reactions using carbon based molecules (a collection of atoms of the same element) by which the matter is taken into a system and used to assist its growth and reproduction and production of waste products. The system inside which these processes occur is the cell. A cell is like a container filled with intricate array of organic (matter belonging to life forms) and inorganic molecules (things having unorganised physical structures like minerals, soil, etc). Codes for cellular processes are contained in very complex molecules: such as the well-known DNA, located in the central portion called nucleus.

The elements most prominent in organic molecules are carbon, hydrogen, oxygen and nitrogen — all commonly found in planets and comets. Phosphorus, also important to life in small quantities is also widely available. Carbon is especially critical because it can combine to make long chains of atoms. In addition to life-forming elements, water was crucial to development of life on the Earth.

Probably within a hundred million years after the Earth was formed, heat from internal radioactivity as well as comet and asteroid impacts melted parts of the Earth’s interior unleashing massive volcanic activity, which released gasses notably water vapour (H2O) and carbon dioxide (CO2). Thus, roughly three and a half billion years ago there were bodies of surface water (even if there were no oceans as such, only primitive, shallow seas) and an atmosphere that was rich in hydrogen, ammonia, water and nitrogen, becoming richer in oxygen. Then, endless lightning produced those building blocks of life beginning with prokaryotes, eukaryotes and viruses, in chain reactions that followed.

Such chemical reaction as described above gave birth to single strand molecules (as described earlier, the same group of atoms that can be reduced finally without the atom losing its basic identity — thus unleashing the chemical “evolution” in the first 500 million years of the cataclysmic birth of the Earth. You may like to call it ‘proto life’.

RNA molecules took 200 million years to develop into viruses, which took another 200 million years of microscopic stage (the first fumbling prokaryotes), which struggled for a painstakingly long 600 million years to branch into bacteria and eukaryotic stages. These primordial, rather primitive life forms took hold of the planet and spread out, or proliferated unrestrained for well over one billion years. It took three and one half billion years for the basics of life to entrench themselves.

In order to understand microscopic life, we must understand how small, or big it was, and the effort by various scientists that went into reaching those conclusions.

The great Dutch microscopic scientist, Anton van Leeuwenhoek (1632- 1723) studied the tiny life for over 50 years, grinding 419 lenses to study it untiringly. But the absence of advanced microscopes prevented him seeing beyond the resolution of his lenses. It was left to Otto Friedrich Muller (1730-1784), and much later to the famous Frenchman, Louis Pasteur (1822-1895) to demonstrate that micro organisms are the cause of infectious diseases, but also what these micro organisms are, and how it led to the study of primitive life of the first three billion years or so. In fact, it was only in 1862 that Julius Cohen (1828-1896) coined a name to bacteria (Latin word meaning: little rods).

The average eukaryotic cell is 10 micrometers in diameter (one micrometer is equal to one millionth of one metre or 1/25400 of an inch). A bacterium (plural: bacteria) is only one or two micrometers across. They are as small as 0.1 micrometer across. Bacteria, needless to say, do not have a nucleus and are very tiny and primitive. They are often called prokaryotic — Greek word meaning ‘before the nucleus’.

The oldest rocks in which prokaryotic cells have been found embedded are as old as 3,500 million years old. For more than 2,000 million years life on Earth existed only in prokaryotic form. It was a world of bacteria without chlorophyll.

The average virus is 0.2 micrometers in diameter. Prokaryotes were 1, 000 times the volume of a typical virus. A eukaryotic had 1,000,000 times the volume.

So much for the world of the small, invisible. You have to read and understand the Word of God to reach similar conclusions.

Now finally Mars. To make it short, life never existed on Mars. I have had considerable difficulty in defending my position over the years, nevertheless holding on to my views grimly but firmly. Not even in prokaryotic or eukaryotic state. For the conditions and environs are too hostile, and unsavoury for any life to emerge on Mars.

If at all Mars does (or did) possess or harbours suitable conditions in the past, or now, just wait for a billion years for it to flourish! Any talk of flying stones carrying microbial life supposed to have landed on the Earth’s South Pole is nothing but unscientific poppycock.

Next on the gas giants of the Solar System.

The writer is a professional astronomer and a former head of PIA Planetarium. He can be reached at astronomerpreone@hotmail.com