HOW WAS THE EARTH FORMED?

PART I

To answer this question, it is advisable to turn firstly to the formation of the Sun and the stars. According to the Big Bang theory the universe started with radiation at a temperature of about 10¹² degrees - a temperature too high for atoms to exist. This was the so-called Cosmic Egg, first postulated by Georges Lemaitre in 1945. Then sudden expansion took place. Rather than calling this the big bang, a better name would be the "Cosmo-genesis", i.e. the beginning and subsequent development or evolution of the universe. The radiant energy was then converted into matter when the temperature dropped below 10¹⁰ degrees. Einstein worked out the relationship between energy and matter and expressed it in the formula E = mc², where E is the energy in ergs; m the mass of the matter produced in grams; and c is the speed of light in centimetres per second, namely 2,99792 x 10¹⁰,which we can call 3 x 10¹⁰ centimetres per second ( a 3 followed by 10 zeros). From this formula we see that the amount of matter produced is given by m = E ÷ c²; so when we look at the amount of matter in the universe, we are forced to admit that the amount of energy E, must have been a quantity unimaginably large.

The matter produced, consisted only of hydrogen and helium in the proportion of 75% to 25% with a slight admixture of lithium, carbon and oxygen. The hydrogen atom consists of one Proton which carries a positive electric charge. This charge is neutralised by the negative charge of an electron outside the nucleus. The mass of the proton is 1836 times the mass of the electron. The nucleus of the helium atom contains two protons and two chargeless particles, called neutrons, with two negative electrons outside the nucleus. The mass of the neutron is approximately equal to that of the proton.

This matter was then fairly evenly dispersed into space while space expanded and the temperature kept falling. The microwave background radiation which was discovered rather accidentally by A A Penzias and R M Milson in 1965, is the remnant of the original radiation. It has since cooled to -270°C. This radiation is very evenly distributed but it does have slight unevennesses so that we can conclude that the matter also had slight concentrations here and there. These concentrations of cold gas very quickly exercised gravitational attraction on the surrounding less concentrated matter, causing the surrounding matter to spiral in on the concentrations because wherever matter occurs, the fabric of the space-time continuum becomes curved and the world lines of gravitational attraction become more and more concentrated in the clumps of matter which became the first galaxies. Because of the spiraling motion, these masses began rotating in the curved space-time continuum. Subsequently everything in the universe had spin. Because the speed of rotation varied with the distance from the centre the particles of matter were constantly overhauled by faster-moving particles nearer the centre. These differential speeds caused the particles to clump together and to serve as nuclei of separate stars. The mass of gas which went to form a star, in its turn, rotated about its own centre of gravity. It is more accurate to say that the gas particles rotated because they were constrained by the curvature of space-time around the centre of concentration of the proto-star.

As the gas became more and more concentrated, the overlying layers exerted more and more pressure on the centre of attraction. We know that increase of pressure, raises the temperature; for example, if one rapidly pumps up a bicycle tyre, the lower end of the pump, where the air becomes compressed, gets so hot that one cannot hold it.

The increase in temperature at the centre (nucleus) of the compressed gas eventually led to the atoms of hydrogen and helium becoming ionised, i.e. losing their electrons, thus forming a plasma which is highly electrically conducting and glows so that the proto-star began to shine. This ionisation came about when the temperature rose to about 10 000°. Despite the high pressure in the nucleus, the ions, consisting of single protons and electrons, moved about freely. At this stage the coagulation of matter could be termed a star-in-the-making.

As the gravitational attraction drew in more and more matter, the inexorable pressure of the overlying layers of gas, caused the temperature in the nucleus to rise ever higher and higher and volume, or size of the clump of gas became greater and greater. The matter in the clump occupied a volume which was so great that the gravitational force experienced by the outlying particles, outside the clump of gas, no longer acted from a single point in the centre of the clump. Thus the outlying particles started describing ellipses around the nucleus. In these elliptical orbits, the particles clumped together to form the nuclei of planets. Meanwhile the proto-star got bigger and hotter. When the temperature of its nucleus reached 10 million degrees, the pressure was so great that the separate protons were crushed into each other. The pressure overcame the force of repulsion between the individual positively charged protons and formed a nucleus of deuterium. Very adroitly one of two protons succeeded in shooting its positive charge out into the surroundings as a positron and the proton had become a changeless particle, a neutron, which could stick to the positive proton. This newly formed nucleus is called deuterium.

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A free proton was then forced into the deuterium and a transformation took place whereby a helium nucleus was formed:

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The transformation into helium set free gammarays, which was radiation at the highest possible frequency. The proto star became a real star when this radiation reached the surface. Two of these helium nuclei, each consisting of two protons and one neutron, i.e. a mass of 3 atomic mass units (amu) were then forced into each other to form a helium nucleus of 2 protons and 2 neutrons;

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Two protons were set free, to start the process all over again. The star had succeeded in transforming hydrogen into helium and in so doing copious amounts of radiation were set free as gammarays at a frequency of 1025 Hertz. These rays, in working their way up to the surface of the star are continually absorbed by the protons and re-emitted again, but each time at a lower frequency - a condition of thermal equilibrium, which can only prevail in the nucleus of a star. By the time these rays reached the surface, the frequency had decreased to 10¹⁴; i.e. they had become visible light. The star had thus begun to shine in all its glory. The gammarays radiated by the star, constitute a loss of mass by the star. The mass of the original 4 protons totaled 4,03252 amu but that of the helium formed was only 4,00389 amu, i.e. a loss of mass of 0,02863 amu had taken place. This constitutes 0,75 of the original four protons. This loss of mass had been converted into energy in the form of gammarays, according to Einstein's equation

E = mc².

While all this was going on in the nucleus of the star, the bodies in the elliptical orbits, the planets, went on accumulating matter from the primeval nebula of cold gas. These planets were hopelessly unfit to harbour life forms. They consisted almost entirely of gas and had only very tiny cores of solid substances. But these planets were not destined to survive because their parent stars very quickly became very massive because of the highly concentrated gas. Because of their great masses the temperatures at their centres rose to hundreds of millions of degrees and they were able to form heavier elements such as carbon, oxygen, nitrogen, neon magnesium, calcium, silicon, until they eventually started forming iron of mass 56 amu. By this time the amount of hydrogen available as fuel had become seriously depleted, so much so that there was a sudden drop in the amount of radiation from the centre. This radiation had up to that time assisted the resistance by the gas to the crushing pressure by the overlying layers which tended to crush the material into a point. When the radiation suddenly decreased, the inexorable pressure of the overlying gas layers, caused the temperature at the centre to rise to 100 million degrees. This sudden rise in temperature had two effects: atoms heavier than helium were produced, such as carbon, oxygen, nitrogen, magnesium, aluminium, silicon and even iron; and the second effect was that a rebound from the centre took place and a large part of the star was blasted into space as a supernova explosion. In this explosion atoms as heavy as uranium were formed. The whole region in the neighbourhood became littered with heavier atoms constituting 1% of the whole. It is masses of supernova explosions such as these that we see today as the quasars.

According to D N Schramm, in his treatise "The Ages of the Elements", there was a peak of supernovae explosions round about 9 milliard ( 9 x 10⁹ ) years ago. The matter shot out into space, vaporised the planets and they became intermixed with the material of the nebula. The first generation of stars and planets had come to an end!

This nebula, enriched with heavy elements, became the source from which the second generation of stars and planets could be born by the same process of accretion ( packing together ) which had produced the first generation of stars. However, the new stars and planets which were formed from this material, contained heavy atoms ( although only 1% ). On average, the second generation of stars was less massive because the matter was now more spread out, After another four milliard years
( i.e. 5 milliard years ago ), a second peak of supernovae explosions took place and once again space was littered with enriched material, now containing as much as 2% of heavier atoms. This material formed the source from which the third generation of stars was formed, one of which happened to be our Sun.

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Jan Eben van Zyl