No Beginning, No End
So time had a beginning right? HEY HEY HEY! Don’t get all religious on me just yet, because The Catholic church seized the Big Bang model in 1951 and declared that it complies with The Bible, sorry folks ¯\_(ツ)_/¯ (many people don’t like the idea that time has a beginning because it hurts their religious sentiments)
Steady State Theory
Well it turns out that a section of cosmologists felt differently… In attempts to avoid the conclusion of “The Birth of Time”, a rival theory to the Big Bang Theory (BBT) was proposed in 1948 by three scientists namely Fred Hoyle, Herman Bondi, and Thomas Gold; this theory was named as the Steady State Theory (SST). In contrast to what BBT claims (that time is 13.8 billion years old) SST orbits around the Perfect Cosmological Principle. Now what does it mean? It states that the universe, taken as a whole, is infinitely old (time is indeterminate), stretches infinitely (has no boundary), and it looks the same in whichever direction you observe it regardless of the instant at which you observe it. In simple words: SST claims that the average density of the universe remains constant as time progresses and expansion occurs. The foundation of this idea you ask? Well…it says that as the universe expands in size and the distance between galaxies (or matter) increases the new galaxies (or matter) are continually being created between the gaps, therefore making the universe look the same at all times and at all points in space. This also means that the amount of light in space (on a larger scale) remains the same regardless of the point of reference in space and time. Although, there is nothing wrong with this theory’s assumption of average distance between galaxies being increased continuously because this has been observed by scientists and many results have been published regarding this, major contributions being that of Hubble’s; however, the rate that SST assumes for this expansion is too slow: just 1 particle the size of hydrogen atom per 6 cubic kilometers of space per year which seems to be rather a modification of the general theory of relativity!
SST is a simple and definite theory in the sense that its assumptions could be tested through observations and much to our delight it has been: a survey done in 1950-60 by a group of scientists at Cambridge led by Martin Ryle which collected radio waves. It showed that most radio sources must lie outside our galaxy, and also that there were more weaker sources than there were strong ones; obviously the weak sources are interpreted to be the distant ones and the stronger ones as being near. Then there appeared to be fewer sources per unit volume of space for nearby sources than for the distant ones. Now this was something really interesting because it meant that we were at the center of a great region in the universe in which sources were gradually increasing, it could also mean that there were more sources in the past (as you go farther in space , you are going back in time). Either explanation contradicts the assumptions of SST. The discovery of CMB by Penzias and Wilson that we discussed in the last article also serves as an observation that proved SST wrong, indicating that the universe was much denser in the past.
Work of Lifshitz and Khalatnikov
Another attempt to debunk the beginning of time was made by two Russian scientists Evgenii Lifshitz and Isaac Khalatnikov (don’t try to pronounce their names unless you know Russian). In 1963, they suggested that Big Bang singularity is a peculiarity of just Friedmann’s models and that it isn’t based on generality of the real universe (which claims that galaxies have a lateral movement besides just moving directly away), so it doesn’t necessarily mean that all the matter in the universe would have existed at one point only very close together. So their idea of expansion was the contracting phase of the universe at some point in the past, the expansion resulted but not due to the Big Bang but the collapse of the universe, the particles did not collide, they only flew past and then away from each other, producing the current expansion. They realized that they were wrong when they studied the models which took into account the irregularities and random velocities of galaxies in the real universe.
Their work was extremely valuable because it showed that the universe could have a singularity if the general theory of relativity was correct. However, it couldn’t answer whether general theory of relativity predicts that we should have a beginning of time. The answer to this came by British physicist, Roger Penrose in 1965. We shall talk about that in subsequent articles. Till then keep looking at the stars.
- By Muhammad Umair Ansari
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