Cosmology

Over the past week, I've been reading a very interesting book entitled "The 4% universe: dark matter, dark energy and the race to discover the rest of reality", written by Richard Panek. This is a subject which has always fascinated me and the book gives good explanations about the subjects covered.

Especially interesting to me at the moment are the discussions about doctorates: in the sciences, these are supposed to follow the scientific method which is composed of three stages:

1. make observations

2. propose a theory which explains those observations

3. make predictions on the basis of the theory.

A good example of the above method is Mendeleev and his periodic table of elements. Various facts were known about the elements which had been isolated by 1869; Mendeleev proposed a theory which could explain those facts, but he also made predictions about elements which had yet to be discovered. When new elements were discovered, their properties were checked against this theory and the predictions confirmed.

Unfortunately, doctoral theories in social sciences (and business administration is placed here) don't usually present testable theories.

The book begins with the discovery of the cosmic background radiation which had been predicted and found by accident in 1965. It then goes on to discuss the work of Vera Rubin who worked - at first in isolation - on galaxy rotation rates. From there, super novae are discussed, and in my opinion, this is where the book gets bogged down, as there are two competing teams and it's difficult (at least, for me) to remember who belongs to which team.

The findings of Rubin (and originally those of Hubble in 1929) show that the galaxies are speeding away from us and that the rate of acceleration is also increasing. The estimated mass of the galaxies cannot account for this, implying that there is mass which we cannot see - the eponymous dark matter (which, to be topical, is the name of Randy Newman's most recent record). Without going into the calculations, it appears that we can only see and measure 4% (4.5%) of the universe!

With a neat piece of synchronicity, it was announced a few days ago that one of the winners of the 2019 Nobel prize for physics is Jim Peebles, who appears frequently in the above book. The citation is for 'theoretical discoveries in physical cosmology'.

Tangentially, Frederik Pohl's "Gateway" series is about cosmology: at the end of the second book, there is discussion of the missing mass (dark matter) and a supposition that someone is causing the universe to contract (which would require even more matter and/or energy) in order to restart the universe with different parameters (for example, the mass ratio between protons and electrons). One character wrote a doctoral thesis on this subject which was not accepted, as it did not produce testable predictions (unlike in real life).

Without going into the subject very deeply, there are about six numbers which are observed that do not evolve from theory; changing these numbers would cause the universe as we know it not to exist, or at least to change drastically (for example, changing the value of one parameter would prevent the existence of stars). This is known as the 'Goldilocks principle', and I own a book by Professor Paul Davies which explains this (unfortunately, the book is harder to read than the Gateway books or even 'The 4% universe'; also I have it in print and not Kindle). Why Goldilocks? Because these numbers produce a universe which allows human beings to exist, and so the universe is 'just right', like Goldilocks' porridge. This is also known as the 'anthropic principle'.

I would love to know how Pohl researched that series and whether he originally conceived just the initial book or the entire series. The style and structure of the first book is different from the others, so there is reason to support the suggestion that the other three books were not originally planned. Also, the first book dates from 1977, which is prior to several large steps in cosmology (as discussed in '4%'; for example, the inflation theory of Guth dates from 1980) whereas the others could have been based on new discoveries and/or theories.