A little look at the Big Bang
This weekend, I went on a one-day course at London’s City Lit to study the Big Bang with tutor Roger O’Brien. I was pleased that I have viewed a number of television programmes and read a few books [the most recent reviewed here] on the subject, because it is quite mind-boggling.
The tutor began by asking us: what is the most fundamental cosmological observation ever made? None of us came up with his answer: it gets dark at night. As he put it, this means that either the sun is the only strong source of light and heat or that all the other sources are immensely distant.
He then went on to explain how we know that these other suns or stars, and the galaxies that they make up, are not just distant but becoming more so. This is called red shift. Spectrum analysis of stars shows a shift towards the red end of the spectrum demonstrating that the star is moving away from us. As he put it, if the universe is expanding, it must previously have been smaller.
Next he explained the concept of isotropy which is the cosmological principle. On the largest scale, the universe looks very similar in all directions. This is further evidence for a Big Bang. Cooling from the Big Bang leads to what is called Cosmic Microwave Background Radiation (CMBR) and CMBR has now been detected, providing still further evidence off the Big Bang explanation.
The statistics are stunning. The period of the Big Bang known as inflation lasted an unbelievable fraction of a second – from 10 to the power of minus 35 to ten to the power of minus 32; since then, the universe has been expanding for around 13.8 billion years; and the process has created approximately 10 to the power of 24 stars (that’s a 1 followed by twenty-four zeros).
The tutor did not even speculate how the Big Bang actually started but he did explore theories about what might happen to the universe in the eons ahead.
Roger O’Brien is a very good teacher, clear and compelling, but he is somewhat sardonic and sceptical. For a long time, he was a supporter of the steady state view of the universe propagated by Fred Hoyle who coined the term Big Bang as a term of derision. Roger confessed that he does not really like the Big Bang theory but accepts that the evidence for it is now overwhelming. He questions the validity of the findings of primordial gravity waves by the Bicep2 project; he is not convinced that dark matter exists; he doubts the existence of worm holes; and he has no time for parallel or multiple universes.
So much to think about that my brain almost had a Big Bang,