It is accepted by almost all astrophysicists that the Universe began 13.77 billion years ago as a dense fire-ball of unimaginable energy that blew apart in a violent explosion giving rise to the stars and planets. (Our universe therefore now consists of an expanding system of Galaxies). The discoveries of Arno Penzias and Robert Wilson who had reason to believe that their Radio telescope had picked up the background hiss of that primeval blast seemed to support this so called “Big Bang” theory,
According to the Big Bang theory, the expansion of the observable universe began with the explosion of a single particle at a definite point in time. Georges Lemaître, (1894-1966), Belgian cosmologist, is considered the father of the Big Bang theory.
Ironically Hoyle the physicist who invented the very phrase itself in 1949, has challenged this notion with his own “steady state continuous creation theory” according to which matter is created continuously instead of all at once.
Astrophysicists, who favour the Big Bang theory (and they seem to be in a majority) feel that two possible futures exists for the expanding universe: the expansion may go on for ever or it may come to a stop one day and then reverse. The determining factor in his choice is the mean density of the Universe.
The Universe is already nearly empty and quite cold. A small fraction of its volume is occupied by matter (stellar bodies) at high densities and temperatures but averaged all over space, the density and temperatures are respectively less than one atom per cubic metre and about -455 degrees Fahrenheit. Billions of years of expansion have cooled and lowered the density of the universe which had originally been incredibly hot and extremely dense.
If we assume that the Universe is continuously expanding what will the future be? At present the universe is dominated by Stars drawing energy from nuclear reactions that convert hydrogen into helium. A typical star will consume all of its hydrogen and burn out; after a spectacular final blaze it will collapse on itself, leaving behind a dark remnant crushed by its own gravity into an object approximately the size of the earth. Our sun will obviously meet the same fate in about five billion years. Cooler, dimmer stars will be able to stretch out their fuel and shine much longer but all the stars in the cosmos will have burned out after a trillion years. Cold planets will continue to circle these orbiting remnants.
The distances between stars are so vast that accidental encounters are exceedingly rare but after say ten raised to the power of 19 years (a figure beyond human comprehension) cold stellar cinders will be perturbed in their orbits by repeated near-collisions. The structure of the galaxies will be enormously altered; their central regions will grow even more dense as the most massive dead stars drift inward, eventually forming a gigantic Black hole encompassing perhaps ten per cent of the galaxies’ original mass. The rest of the stars in each galaxy will be thrown outward in reaction. Some will take up distant orbits slowly circling the central Black hole, others will escape entirely to drift alone. These close stellar encounters will also tear planets away from their parent stars and most will be ejected from their galaxies into the void.
The burnt out stars that do not escape cannot continue to orbit the central Black Hole forever. As they move in their orbits they will slightly disturb the gravitational field of the galaxy, resulting in gradual loss of minute amounts of energy, and the dead stars spiralling slowly inward. The central Black holes will ultimately absorb those captive objects. This process will take ten raised to the power of thirty years, a period totally beyond human comprehension. Most of the Universe’s mass will then be in the Black holes, the remainder in isolated cold stars and planets.
Gradually the Black holes will emit a trickle of radiation and even a few elementary particles; thus the matter and energy, trapped within the Black-holes will “tunnel” out – a process based on Heisenberg’s uncertainty principle according to which no particle can be perfectly contained within a finite space. This implies that at any moment a confined object has a probability however small, of escaping. The values of probability are so minute for objects of ordinary mass and size that tunneling never occurs in our daily experience. However this phenomenon which is well understood gives rise to many common atomic processes including radioactivity. The effect of the large scale tunneling will be to cause each object in the Universe to organise itself into a perfect sphere in ten raised to the power of 65 years.
After about 10 raised to the power of 100 years (yet another figure totally beyond human comprehension) tunneling will destroy all the black holes that have replaced the galaxies. In this way most of the Universe’s present matter will be transmuted into radio-active energy; that will be dissipated by the Universe’s expansion leaving only the escaped dead stars and planets. Through either fusion or radioactive decay all elements will be eventually transformed into iron. Thus all surviving objects will become solid iron after a period of 10 raised to the power of 100 years to 10 raised to the power of 200 years. (The number of Zeroes that one needs to write the number of years indicated above is indeed staggering. The human brain cannot conceive of such such figures!); The earth itself will resemble an enormous ball bearing thousands of miles in diameter, a smooth featureless and cold iron sphere drifting alone in an utterly dark void. Nothing more will happen for a very very long time – even by the standards of time scale of the cosmos.
The ice cold spherical iron remnants of stars and planets will suffer a final stress. Gravity will try to compress them into a Black hole but won’t be able to overcome the pressure associated with their high density. However the remains- perhaps helped by gravity – may spontaneously compress themselves into a Black hole by a quantum mechanical process, but one of such low probability that an inconceivably long period, 10 raised to the power of 77 years must pass before this would be likely to happen.
After each object becomes a Black hole it will evaporate into radiation through the tunneling process. Thus all matter will eventually disperse leaving a Universe containing only slowly fading radiation. When the last bit of radiation passes with a metaphorical hiss what was once our Universe will yield to eternal emptiness. The long dead earth will have also compressed into a Black-hole less than one inch across. This unimaginably concentrated mass – so dense that not even light can escape from it—will also leak away in an initially slow but ever accelerating trickle of radiation eventually evaporating entirely.
We are reminded of Shakespeare’s powerful lines in “The Tempest”
“The cloud-capp’d towers, the gorgeous palaces,
The solemn temples, the great globe itself,
Yea, all which it inherit, shall dissolve,
And, like this insubstantial pageant faded,
Leave not a rack behind: We are such stuff
As dreams are made on, and our little life
Is rounded with a sleep”.
On the other hand Hoyle and other advocates of the “steady state continuous creation Theory” say that the expanding universe is an “illusion”. It seems to expand only because rulers we use to measure it are themselves shrinking due to various changes in the atoms as a result of inter-actions and passage of time. In other words the universe seems to be receding only because the atoms within the various instruments that are used to measure distances have become older more massive and therefore smaller. Hoyle feels that there must have been a time in the past when all the matter in the Universe was infinitely young; had not yet experienced interactions and hence had zero age and zero mass (This is the moment when according to “mainstream” astrophysicists the Big Bang had taken place). Hoyle calls this point in time the moment of “Zero mass surface”.
Before the moment of zero mass surface Hoyle postulated an earlier universe different from ours. Our Universe has positive interactions between bits of matter that build up the mass of subatomic particles. But in this earlier Universe of Hoyle, interactions were negative. The atoms left over from the death of the earlier Universe leak across into our Universe without fireworks or fuss merely appearing as high red-shift immigrants. The red shift of the distant galaxies is thus due to the immaturity of matter rather than, due to expansion. Hoyle’s theory is of course diametrically opposed to main stream thought in modern astronomy. But he is too distinguished an astrophysicist to be brushed aside or dismissed out of hand. Such controversies like the one narrated above have kept astrophysics in turmoil for the past few decades. Perhaps only someone like Stephen Hawking can even venture to reconcile such e viewpoints and find an acceptable solution.
Four Indian scientists, have now challenged the Big Bang according to which the Universe was born out of a singularity, a highly compressed, dense and microscopic point, which exploded with a huge force some 13.8 billion years ago. Everything arising from that singularity have been moving outwards in all directions and all galaxies and other cosmic matter, had been forming at different stages through time until now.
The Big Bang theory was based on observation of the ‘red shift’ in the light spectrum (according to Doppler, light wavelength emitted from an astronomical object that is moving away from us exhibits a shift in the light spectrum towards the red end). The Big Bang theory is supported by the understanding that the shift of light towards the red band in the spectrum is continuous and uniform in nature — an indication of all matter (galaxies and all cosmic matter) moving outwards steadily, but at great speed. This would mean that it all began from a single starting point in the centre of the Universe (singularity), which is how the Big Bang theory was popularised among astrophysicists.
The four Indian astrophysicists, referred to above, used a technique called singular value decomposition, to conclude that the red shift does not occur in a continuous and uniform manner, but in recurring stages, in what they refer to as” periodicity in red shift”.
In a research paper published recently in a prestigious international journal “Astronomy and Astrophysics” the four scientists reported their findings. They claimed that the superiority of the singular value decomposition method in analysing red shift periodicity, lay in the fact that they analysed very large data samples and used a method, which is more robust than the method usually dealt with by astronomers.
Interestingly, although this is not the first time that the Big Bang theory has been challenged, the previous challenges were based on much smaller sample sizes. The renowned physicist, late Stephen Hawking had stated that the criticism levelled against the theories challenging the Big Bang is because the samples of red shifts that were analysed were rather small and selected in a heterogeneous manner, which made it hard to assess their significance.
In the past astrophysicists had rejected the variable mass theory of Hoyle and Narlikar, which hypothesised that quasars are born in and ejected from the nuclei of parent galaxies as massless objects and the particle masses in them systematically increase with epoch.The four scientists claimed that their theory may support some alternate models like Hoyle-Narlikar mass theory. The world needs another Einstein or Hawking to throw light on these extremely complex concepts.