A series of fortunate events

Why is the world the way it is? How did we get here? Does everything happen for a reason or are some things left to chance? Philosophers and theologians have pondered these questions for millennia, but startling scientific discoveries over the past half century are revealing that we live in a world driven by chance.

In this talk, Sean B Carroll told the story of the awesome power of chance and how it is the surprising source of all the beauty and diversity in the living world.

Sean B Carroll is an award-winning scientist, writer, educator, and film producer. He is Vice President for Science Education at the Howard Hughes Medical Institute and the Balo-Simon Chair of Biology at the University of Maryland. His books include The Serengeti Rules (Princeton), Brave Genius, and Remarkable Creatures, which was a finalist for the National Book Award. He lives in Chevy Chase, Maryland. Twitter @SeanBiolCarroll


Sean B. Carroll (born September 17, 1960) is an American evolutionary developmental biologist, author, educator and executive producer. He is the Allan Wilson Professor of Molecular Biology and Genetics at the University of Wisconsin–Madison. His studies focus on the evolution of cis-regulatory elements in the regulation of gene expression in the context of biological development, using Drosophila as a model system. He is a member of the National Academy of Sciences, of the American Philosophical Society (2007), of the American Academy of Arts and Sciences and the American Association for Advancement of Science, as well as a Howard Hughes Medical Institute investigator.




The following are notes from the on-line lecture. Even though I could stop the video and go back over things there are likely to be mistakes because I haven’t heard things correctly or not understood them. I hope Professor Carroll and my readers will forgive any mistakes and let me know what I got wrong.

Some questions posed.

Why is the planet the way it is?

How did we get here?

Does everything happen for a reason or are some things left to chance?

Ancient philosophers and theologians have been pondering these things for a very long time.


Leucippus (480-420 BCE) is reported in some ancient sources to have been a philosopher who was the earliest Greek to develop the theory of atomism—the idea that everything is composed entirely of various imperishable, indivisible elements called atoms.


He said “Nothing occurs at random, but everything for a reason and by necessity”


Lucius Annaeus Seneca (4 BCE – AD 65), also known as Seneca the Younger, was a Hispano-Roman Stoic philosopher, statesman, dramatist, and—in one work—satirist from the Silver Age of Latin literature.


Ancient bust of Seneca

He said “We live as it were by chance, and by chance we are governed”



The Triumph of Saint Augustine painted by Claudio Coello, circa. 1664

Augustine of Hippo (13 November 354 – 28 August 430 AD), also known as Saint Augustine, was a theologian, philosopher, and the bishop of Hippo Regius in Numidia, Roman North Africa. His writings influenced the development of Western philosophy and Western Christianity, and he is viewed as one of the most important Church Fathers of the Latin Church in the Patristic Period. His many important works include The City of God, On Christian Doctrine, and Confessions.

Augustine took the view that, if a literal interpretation contradicts science and humans’ God-given reason, the Biblical text should be interpreted metaphorically. While each passage of Scripture has a literal sense, this “literal sense” does not always mean the Scriptures are mere history; at times they are rather an extended metaphor.



Blaise Pascal (19 June 1623 – 19 August 1662) was a French mathematician, physicist, inventor, philosopher, writer and Catholic theologian.


Pascal argues that a rational person should live as though God exists and seek to believe in God. If God does not actually exist, such a person will have only a finite loss (some pleasures, luxury, etc.), whereas if God does exist, he stands to receive infinite gains (as represented by eternity in Heaven) and avoid infinite losses (eternity in Hell).

Pascal’s Wager was based on the idea of the Christian God, though similar arguments have occurred in other religious traditions. The original wager was set out in Pascal’s posthumously published Pensées (“Thoughts”), an assembly of previously unpublished notes.

Historically, Pascal’s wager was groundbreaking because it charted new territory in probability theory, marked the first formal use of decision theory, existentialism, pragmatism, and voluntarism.

And a “modern Philosopher’s” take on the subject?



Stephen Tyrone Colbert (born May 13, 1964) is an American comedian, writer, producer, political commentator, actor, and television host.

He said “When someone says everything happens for a reason, I push them down the stairs and say, ‘Do you know why I did that?’ “

Nothing puts the comment of “everything happens for a reason” to the test, like trauma.



Seth Woodbury MacFarlane (born October 26, 1973) is an American actor, animator, writer, producer, director, comedian, and singer.

The actor has related how he was due to fly home to the USA on the 11th September 2001, but he was 30 minutes too late. Whilst he was waiting for a flight home the next day, he saw the news coverage about the planes being flown into the twin towers (he should have been on one of them).


The September 11 attacks, often referred to as 9/11, were a series of four coordinated terrorist attacks by the Islamist terrorist group Al-Qaeda against the United States on the morning of Tuesday, September 11, 2001. The attacks resulted in 2,977 fatalities, over 25,000 injuries, and substantial long-term health consequences, in addition to at least $10 billion in infrastructure and property damage. It is the single deadliest terrorist attack in human history and the single deadliest incident for firefighters and law enforcement officers in the history of the United States, with 343 and 72 killed, respectively.


Another actor who missed one of the flights was Mark Wahlberg



Mark Robert Michael Wahlberg (born June 5, 1971) is an American actor, producer, restaurateur and former rapper.

Because they missed their flights, they lived and were able to make films together like Ted!!!!!!!!!!!!!!!!!!




Ted is a 2012 American comedy film directed by Seth MacFarlane and written by MacFarlane, Alec Sulkin, and Wellesley Wild. The film stars Mark Wahlberg and Mila Kunis, with Joel McHale and Giovanni Ribisi in supporting roles, with MacFarlane providing the voice and motion capture of the title character. The film tells the story of John Bennett, a Boston native whose childhood wish brings his teddy bear friend Ted to life. However, in adulthood, Ted prevents John and his love interest Lori Collins from moving on with their lives.

Why were these two actor’s lives spared?

What a difference 30 minutes can make.

Scientists have done a lot to work out why the Earth is like it is. It has been buffeted by cosmological and geological accidents which is how we humans evolved to be here.

Probing human biology and the factors that impact our lives, we’ve caught chance “red-handed”.

Probing that line between life and death

Professor Carroll continued his talk by highlighting a few eventsthat have been driven by chance.

What does that mean for how people think about themselves?

Event 1

Geologists have been interested in the rock formation in Gubbio, Italy.


Gubbio is a town and comune in the far northeastern part of the Italian province of Perugia (Umbria). It is located on the lowest slope of Mt. Ingino, a small mountain of the Apennines.


Gubbio is also known among geologists and palaeontologists as the discovery place of what was at first called the “Gubbio layer”, a sedimentary layer enriched in iridium that was exposed by a roadcut outside of town. This thin, dark band of sediment marks the Cretaceous–Paleogene boundary, also known as the K–T boundary or K–Pg boundary, between the Cretaceous and Paleogene geological periods about 66 million years ago, and was formed by infalling debris from the gigantic meteor impact probably responsible for the mass extinction of the dinosaurs. Its iridium, a heavy metal rare on Earth’s surface, is plentiful in extraterrestrial material such as comets and asteroids. It also contains small globules of glassy material called tektites, formed in the initial impact. Discovered at Gubbio, the Cretaceous–Paleogene boundary is also visible at many places all over the world. The characteristics of this boundary layer support the theory that a devastating meteorite impact, with accompanying ecological and climatic disturbance, was directly responsible for the Cretaceous–Paleogene extinction event.


In the 1980s Walter Alvarez saw an interesting pattern in the rock found just outside of town.



Luis and Walter Alvarez (L-R) at the K-T Boundary in Gubbio, Italy 1981

Walter Alvarez (born October 3, 1940) is a professor in the Earth and Planetary Science department at the University of California, Berkeley. He is most widely known for the theory that dinosaurs were killed by an asteroid impact, developed in collaboration with his father, Nobel Prize winning physicist Luis Alvarez.


Luis Walter Alvarez (June 13, 1911 – September 1, 1988) was an American experimental physicist, inventor, and professor who was awarded the Nobel Prize in Physics in 1968 for development of the hydrogen bubble chamber enabling discovery of resonance states in particle physics. (Well I had to get some physics in somehow)

Professor Alvarez noticed in the large stack of limestone layers that there was a switch in colour from white at the bottom to red above. Between the two different coloured layers that there was a weird layer of greyish clay (indicated by the position of the coin in the image below left).


The clay layer illustrated an important moment in time 66 million years ago. A very unlucky day for most of the living things around at the time, but very fortunate for us humans.

Being limestone, a sedimentary rock, the rock formation could have been the floor of an ancient sea bed. The layers included tiny bundles of single celled fossils.

These single celled organisms, called Foraminifera, made up part of the plankton community and were part of the food web. When they died, they helped to form limestone, and this rock got pushed up by tectonic forces.


Foraminifera (Latin for “hole bearers”; informally called “forams“) are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a “test”) of diverse forms and materials. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic), while a smaller number float in the water column at various depths (i.e., are planktonic).

Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure. These shells are commonly made of calcium carbonate or agglutinated sediment particles. Over 50,000 species are recognized, both living (10,000) and fossil (40,000). They are usually less than 1 mm in size, but some are much larger, the largest species reaching up to 20 cm.




Electron micrograph of late Cretaceous Forams. Photo by Brian Huber

The white layer on the bottom contained a wide variety of Forams but the upper red layer only contained a few smaller species. The thin layer of clay lacked fossils altogether. Professor Alvarez realised something dramatic must have happened in the ocean that would have driven many species of organisms extinct in a short period of time.


The “boundary” clay line is also found in terrestrial deposits in western USA. The pocket knife in the above left image provides a scale and points to the boundary that is a dividing line between two worlds, where the division occurred 66 million years ago.

Below the boundary were the rocks of the cretaceous period, which made up the last third of the dinosaur age (the age of reptiles).


The Cretaceous is a geological period that lasted from about 145 to 66 million years ago (mya). It is the third and final period of the Mesozoic Era, as well as the longest. The name is derived from the Latin creta, ‘chalk’. It is usually abbreviated K, for its German translation Kreide.


Above the boundary line were the rocks of the Paleogene era, where there were no dinosaur but marls the beginning of the age of mammals.


The Paleogene (also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 million years ago (Mya) to the beginning of the Neogene Period 23.03 Mya.

What could have caused the major change to happen. To cause the loss of tiny plankton and enormous dinosaurs.

Traces of iridium were found in the thin clay layer that indicated that whatever caused the change wasn’t something on Earth but something from space.



Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is considered to be the second-densest metal (after osmium) with a density of 22.56 g/cm3 as defined by experimental X-ray crystallography. However, at room temperature and standard atmospheric pressure, iridium has been calculated to have a density of 22.65 g/cm3. Still, the experimental X-ray crystallography value is considered to be the most accurate, as such iridium is considered to be the second densest element. It is the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.

Iridium was discovered in 1803 among insoluble impurities in natural platinum. T was named iridium after the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colours of its salts. Iridium is one of the rarest elements in Earth’s crust, with annual production and consumption of only three tonnes. 191Ir and 193Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant.

Iridium is found in meteorites in much higher abundance than in the Earth’s crust. For this reason, the unusually high abundance of iridium in the clay layer at the Cretaceous–Paleogene boundary gave rise to the Alvarez hypothesis that the impact of a massive extraterrestrial object caused the extinction of dinosaurs and many other species 66 million years ago. Similarly, an iridium anomaly in core samples from the Pacific Ocean suggested the Eltanin impact of about 2.5 million years ago.


According to geological evidence an asteroid approximately 10km across hit the Earth about 66 million years ago at a speed of about 22km/s





The asteroid hit the Yucatán Peninsula


The Yucatán Peninsula in south eastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel. The peninsula lies east of the Isthmus of Tehuantepec, a northeastern geographic partition separating the region of Central America from the rest of North America. It is approximately 181,000 km2 in area, and is almost entirely composed of limestone.



The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its centre is located offshore near the town of Chicxulub, after which the crater is named. It was formed when a large asteroid or comet about 11 to 81 kilometres in diameter, known as the Chicxulub impactor, struck the Earth. The date of the impact coincides precisely with the Cretaceous–Paleogene boundary (commonly known as the “K–Pg boundary”), slightly more than 66 million years ago, and a widely accepted theory is that worldwide climate disruption from the event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth became extinct, including all non-avian dinosaurs.

The speed of the asteroid was such that if the impact had been 30 minutes earlier the asteroid would have fallen in the Atlantic Ocean and if it had been 30 minutes later it would have fallen in the Pacific Ocean and no mass extinction would have happened.

During the impact, the kinetic energy in the asteroid (or energy of motion) created an explosion, blowing debris of dust, soil, and rocks in all directions, not only into the atmosphere, but out into space, where it fell back into the top of the atmosphere.

Superheated air, carbon dioxide and sulphur dioxide formed a plume, along with vapourised rock which travelled faster than the Earth’s escape velocity to travel beyond the atmosphere.


In physics (specifically, celestial mechanics), escape velocity is the minimum speed needed for a free, non-propelled object to escape from the gravitational influence of a massive body, that is, to achieve an infinite distance from it. Escape velocity is a function of the mass of the body and distance to the centre of mass of the body.

The material that fell back to Earth rained down at speeds of several thousand km per hour heating the air to between 200 and 300 degrees Celsius, triggering global wildfires. Trillions of red-hot bits of rock producing hell on Earth (if you believe in hell)



Early calculations in the 1980s (using in part ideas worked out by Carl Sagan and his colleagues) showed that the impact plume produces so much dust and soot entered the high atmosphere that the Earth was shrouded in a dust layer that blocked sunlight for several weeks or months (some geologists think that the blackout could have lasted 10 to 30 years). This would have killed some plants, collapsing the food chain.

Later calculations indicated that for the first few hours after the impact, rocky debris would have fallen back into the high atmosphere, creating a storm of glowing fireballs in the sky. The radiant energy from these would have heated the surface to boiling temperatures for some minutes, and would have been enough to kill many animals and plants on the surface. However, in regions of heavy rainstorms or snowstorms, these organisms would have survived the first few hours. Sea creatures would have been buffered from effects in the first hours, but plankton on the surface might have died out over the weeks of darkness, decreasing the food supply for small fish, which affected the bigger fish, and so on.

These examples show how hard it is to predict the exact effects of the impact. Many species who lived on the surface (such as dinosaurs) might have been wiped out in hours or weeks. Species who lived in burrows, or hibernated (like some mammals) might have survived. This may explain why mammals replaced giant reptiles after the impact. Tiny primitive mammals may have emerged from their dens, to find that their giant reptile competitors were mostly gone.

Global temperature would then have dropped at least 10oC

Three-quarters of all plant and animal species, including the great dinosaurs, become extinct.

Evidence for the Impact Event

There are now many lines of evidence to prove that a relatively large impact happened 65 My ago.

The iridium excess in the 65 My-old soil layer has been confirmed at many points around the world.

The same soil layer contains grains of quartz that were deformed by high shock pressures, as would occur in a giant explosion. (The deformation is a microscopic structure called “twinning,” in the crystals).

The same soil layer contains enough soot to correspond to burning down all of the forests of the world. This suggests that massive fires were touched off at the time of impact.

The same soil layer, especially around the Gulf of Mexico, contains massive deposits of tumbled boulders, as would be generated in a large tsunami, or “tidal wave.” The geographic distribution of tsunami deposits suggest the impact was in the Caribbean area.

After a decade of searching, scientists in 1990 identified the crater associated with this material. It is no longer visible on the surface of the Earth, but is buried under sediments. It straddles the coast of Yucatan. It is revealed by mapping the strength of the gravity field over that area, and by drilling; it has been dated to 65 My old.

Astronomers have charted numerous asteroids that cross Earth’s orbit. From studies of orbit statistics, it is estimated that asteroids of 10 km size can hit the earth roughly every 100 My or so — which fits with the idea that we actually did get hit 65 My ago by an object this size. (Smaller hits are much more common).

The Mother of all accidents

The destructive power of the plume depended upon the mineral content of rocks at the impact site

Only 1-13% of the Earth’s surface contained the right kind of rocks to trigger mass extinction, so with the Earth rotating at about 1609km per hour the asteroid could have ended up in the Atlantic ocean 30 minutes earlier or the Pacific 30 minutes later.

The dinosaur descendants would still be here, we would not and Seth and Mark would not have made the TED films

Event 2

Fertilisation and the moment of conception






Chance is very important in fertilisation.

Women are actually born with all the eggs that could possibly be released between puberty and the menopause. Typically, they will only release one egg a month. There is no reason why one egg matures and is released over the others.


Millions of sperm are ejaculated but initially they are not ready to fertilise the egg. Some of these undergo a series of changes known collectively as capacitation once they have entered the vagina which makes them hyperactive However the female’s immune system starts to work against them so relatively few sperm actually reach the egg. The egg itself has to be in just the right place within the fallopian tube.

Only one sperm is needed to fertilise the egg. It is just chance that one sperm can do this over the remaining sperm that reach the egg.

Once one sperm has got inside the egg the surface of the egg undergoes physical and chemical changes that prevent any other sperm entering the egg.






Once fertilisation has taken place embryonic development can begin, but even getting a pregnancy to full term is a matter of chance. Will the bundle of cells implant on the uterus wall properly?

The fertilised egg is the joining of genomes. Half came from the sperm and half came from the unfertilised egg. The chromosomes from each have a unique mixture of genes from each parent. I am very grateful for the unique combination that gave me red hair (although the colour comes from packets of dye now) but I would have like longer legs.

No two fertilised eggs will ever be the same.


By each contributing 23 chromosomes, how many genetically unique children could your parents have?

23? 46? 92? 70 trillion?

Each of us is a one in a 70 trillion event (worse odds than winning the UK lottery).

The accident of all mothers

Breaking down the maths

Number of possible chromosome combinations from dad is 2 x 1023 = 8388608 (although dad does determine if the baby is a boy or a girl)

Number of possible chromosome combinations from mum is 2 x 1023 = 8388608

Number of possible combinations from sperm and egg are 8388608 x 8388608

To give 70368744177664 unique children

This enormous number is actually an underestimate because of another important contributor to chance and that is mistakes during the copying of DNA.


In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. The cell possesses the distinctive property of division, which makes replication of DNA essential.


DNA replication: The double helix is un’zipped’ and unwound, then each separated strand (turquoise) acts as a template for replicating a new partner strand (green). Nucleotides (bases) are matched to synthesize the new partner strands into two new double helices.



A chromosome is a long DNA molecule with part or all of the genetic material.


Sex cells are formed through a particular kind of cell division called meiosis. Unlike in normal cell division (mitosis), the genetic material of the original (parent) cell is divided up twice. This means the double helix unzips and each half goes into its own sex cell. This means that any mistakes in the copying mentioned above means the mistakes could end up in the sex cells (sperm or unfertilised egg).

Meiosis can be summarised as follows:

1) As in most other cells in the body, the nucleus of the original cell contains the person’s full set of genetic information. This information is stored in the form of long threads (strands) of DNA – in the chromosomes.

2) Before the original cell divides the first time, all of the genetic material is replicated: One copy is made of each chromosome.

3) The DNA strands become more tightly packed into a condensed form and can be seen under a microscope. Each chromosome and its copy remain attached in one place.

4) As in many other living things, chromosomes in humans always come in pairs. Unlike in “normal” cell division (mitosis), in meiosis the chromosome pairs first line up along the centre of the cell.

5) The pairs separate there. The individual chromosomes then move to opposite sides of the cell, together with their attached copy. The cell membrane starts pinching inward to form two separate cells.

6) A second cell division follows: The copies of the chromosomes separate.

7) So, the parent (original) cell gives rise to four sex cells. The nucleus of each sex cell contains half of the original genetic material.

8) In men, these cells develop into sperm cells. In women, only one of the four sex cells becomes an egg cell that can be fertilized. During meiosis, it receives most of the cell body of the parent cell. The three smaller cells – referred to as polar bodies – break down and disappear.

Think about sperm and egg as containing letters. Each is made up of 3 billion letters. Changing one of these letters can completely change the “meaning”.

To illustrate the effect of how easy it is to change the meaning by mixing/changing letters Professor Carrol came up with a piece of printed text where there were three mistakes. Now the text came from an article about baseball (I think) so I wouldn’t have a clue what was right and what was wrong so I won’t include it in my report, but he did go on to use an example I was familiar with.


The King James Version (KJV), also known as the King James Bible (KJB), sometimes as the English version of 1611, or simply the Authorized Version (AV), is an English translation of the Christian Bible for the Church of England, commissioned in 1604 and completed as well as published in 1611 under the sponsorship of James VI (of Scotland) and I (of England).

It was first printed by John Norton & Robert Barker, both the King’s Printer, and was the third translation into English approved by the English Church authorities.

The problem arose during a reprint.


Wicked Bible, sometimes called Adulterous Bible or Sinners’ Bible, is an edition of the Bible published in 1631 by Robert Barker and Martin Lucas, the royal printers in London, meant to be a reprint of the King James Bible. The name is derived from a mistake made by the compositors: in the Ten Commandments (Exodus 20:14), the word “not” in the sentence “Thou shalt not commit adultery” was omitted, thus changing the sentence into “Thou shalt commit adultery”. This blunder was spread in a number of copies. About a year later (because it took a year for the mistake to be detected), the publishers of the Wicked Bible were called to the Star Chamber and fined £300 (equivalent to £50,322 in 2019) and deprived of their printing license. The fact that this edition of the Bible contained such a flagrant mistake outraged Charles I and George Abbot, the Archbishop of Canterbury.


The majority of the Wicked Bible’s copies were immediately cancelled and destroyed, and the number of extant copies remaining today, which are considered highly valuable by collectors, is thought to be relatively low. One copy is in the collection of rare books in the New York Public Library and is very rarely made accessible; another can be seen in the Dunham Bible Museum in Houston, Texas, US. The British Library in London had a copy.

Charles I revoked the printers’ license and one of the printers died in a debtors prison. The danger of missing out one three letter word led to the death of a man.

This also happens in life’s alphabet.

What a difference one typo can make

The original text is KKKYMMKHL and is part of Simian Immunodeficiency Virus (SIV)

Just one typo turns it into KKKYRMKHL and has caused the death of more than 33 million people – it is the corresponding part of the HIV virus

The mutation of M turning to R enables the chimpanzee SIV to infect humans, which occurred by accident at least three times and triggered the AIDS pandemic.

The cause of such changes as described earlier is to do with the DNA molecule.


Deoxyribonucleic acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.


DNA was first isolated by the Swiss physician Friedrich Miescher who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages.

In 1909, Phoebus Levene identified the base, sugar, and phosphate nucleotide unit of the RNA (then named “yeast nucleic acid”). In 1929, Levene identified deoxyribose sugar in “thymus nucleic acid” (DNA).

In 1933, while studying virgin sea urchin eggs, Jean Brachet suggested that DNA is found in the cell nucleus and that RNA is present exclusively in the cytoplasm.

In 1937, William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure.

In 1943, Oswald Avery, along with co-workers Colin MacLeod and Maclyn McCarty, identified DNA as the transforming principle, supporting Griffith’s suggestion (Avery–MacLeod–McCarty experiment). DNA’s role in heredity was confirmed in 1952 when Alfred Hershey and Martha Chase in the Hershey–Chase experiment showed that DNA is the genetic material of the enterobacteria phage T2.

Late in 1951, Francis Crick started working with James Watson at the Cavendish Laboratory within the University of Cambridge.

In May 1952, Raymond Gosling a graduate student working under the supervision of Rosalind Franklin took an X-ray diffraction image, labelled as “Photo 51”, at high hydration levels of DNA. This photo was given to Watson and Crick by Maurice Wilkins and was critical to their obtaining the correct structure of DNA. Franklin told Crick and Watson that the backbones had to be on the outside. Her identification of the space group for DNA crystals revealed to Crick that the two DNA strands were antiparallel.

In February 1953, Watson and Crick completed their model, which is now accepted as the first correct model of the double-helix of DNA. On 28 February 1953 Crick interrupted patrons’ lunchtime at The Eagle pub in Cambridge to announce that he and Watson had “discovered the secret of life”



Francis Harry Compton Crick OM FRS (8 June 1916 – 28 July 2004) was a British molecular biologist, biophysicist, and neuroscientist.



James Dewey Watson KBE (born April 6, 1928) is an American molecular biologist, geneticist and zoologist.



Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) was an English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, coal, and graphite.[2] Although her works on coal and viruses were appreciated in her lifetime, her contributions to the discovery of the structure of DNA were largely recognised posthumously.



Maurice Hugh Frederick Wilkins CBE FRS (15 December 1916 – 5 October 2004) was a New Zealand-born British biophysicist and Nobel laureate whose research spanned multiple areas of physics and biophysics, contributing to the scientific understanding of phosphorescence, isotope separation, optical microscopy and X-ray diffraction, and to the development of radar. He is best known for his work at King’s College London on the structure of DNA.



Raymond George Gosling (15 July 1926 – 18 May 2015) was a British scientist. While a PhD student at King’s College, London he worked under the supervision of Rosalind Franklin. Their crystallographic experiments, together with those of Maurice Wilkins of the same laboratory, produced data that helped James Watson and Francis Crick to infer the structure of DNA.



Photo 51 is an X-ray diffraction image of a paracrystalline gel composed of DNA fibre taken by Raymond Gosling, a graduate student working under the supervision of Rosalind Franklin in May 1952 at King’s College London, while working in Sir John Randall’s group. The image was tagged “photo 51” because it was the 51st diffraction photograph that Franklin and Gosling had taken. It was critical evidence in identifying the structure of DNA.

The discovery of the rule of base pairing that holds the double helix together



Adenine is always paired with Thymine

Guanine is always paired with Cytosine


Right, a G.C base pair with three hydrogen bonds. Left, an A.T base pair with two hydrogen bonds. Non-covalent hydrogen bonds between the bases are shown as dashed lines. The wiggly lines stand for the connection to the pentose sugar and point in the direction of the minor groove.


Erwin Chargaff (11 August 1905 – 20 June 2002) was an Austro-Hungarian-born American biochemist, writer, Bucovinian Jew, who emigrated to the United States during the Nazi era and was a professor of biochemistry at Columbia University medical school.


Through careful experimentation, Chargaff discovered two rules, called Chargaff’s rules, that helped lead to the discovery of the double helix structure of DNA.

The first parity rule was that in DNA the number of guanine units is equal to the number of cytosine units, and the number of adenine units is equal to the number of thymine units. This hinted at the base pair makeup of DNA.

The second parity rule was discovered in 1968. It states that, in single-stranded DNA, the number of adenine units is approximately equal to that of thymine, and the number of cytosine units is approximately equal to that of guanine.

He also observed that the relative amounts of guanine, cytosine, adenine and thymine bases vary from one species to another. This hinted that DNA rather than protein could be the genetic material.

G and C are located on opposite strands of the double helix as are A and T.

A footnote to the DNA discovery involves chemistry (a minor branch of physics).



Bax et al.

The bases occur in two forms, or tautomers, that differ by the position of one H atom on the larger ring.


Tautomers are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. This reaction commonly results in the relocation of a proton. Tautomerism is for example relevant to the behaviour of amino acids and nucleic acids, two of the fundamental building blocks of life.


In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct bonds between them.

The concept of tautomerizations is called tautomerism. Tautomerism is also called desmotropism. The chemical reaction interconverting the two is called tautomerization.

The keto form of the bases is the most common

Originally Watson only knew about the enol form but he learnt from a colleague that the keto form is the most common

Different forms bond with different bases.

Scientists have only just been able to capture the transformation of one form to another.

The enol form is fleeting (stochastic), lasting about 1/1000th of a second before flipping back to the keto form


But, if the copying machinery (moving at about 1000 bases per second) happens, by chance, to pass when the enol form is present, the wrong bases is inserted, creating a mutation. A completely random process.



The event at the root of mutation is an inescapable, fundamental matter of physics (yay – physics underpins everything) – a quantum transition between chemical states – a chance shape-shift at the atomic level.

Mutation is a Feature, not a Bug in DNA

Mutations can occur in any organism and endows DNA with its properties,

Change and evolution are inevitable

Chance is the source of all innovation, beauty, and diversity in the living world


An example of this process is the Antarctic eelpout


Photo by Christina Cheng

This fish can live in very cold conditions (-1.8oC), the Antarctic ocean.

The enemy of fish here is ice – small ice crystals. If they get into the fish, through the mouth or gills, larger ice crystal can form and reduce blood flow.

A key invention – Antifreeze

The Antarctic eelpout has evolved to produce a type of anti-freeze. -2.1oC is the temperature below which these fish freeze – luckily colder than the ocean in which the fish live.


The fish’s blood plasma is chock full of antifreeze protein.

The anti-freeze binds to small ice crystals and prevents them from growing larger.

The antifreeze gene arose from a small piece of DNA code for an enzyme with a different function.

We can track the generation of the genetic code and how it evolved into a completely different gene. It gives us a forensic trail of how this mutation arose. It shows how a chance mutation is an inventor.

The antifreeze gene looked like a gene found in other fish.


Cheng et al. PNAS (2010)

The SAS protein enzyme is involved in making a certain sugar. The antifreeze gene is very like the tail end of the SAS gene.

The reason for the resemblance came from some expert sleuthing by looking at other fish.

Antifreeze gene evolved from part of the SAS gene. A core of the SAS gene is deleted leaving behind the part that gave the ice-binding property. This chunk encoded a protein that on its own could bind to the small ice crystals. These genes went on to make copies expanding to more than 30 which enables the fish to make lots of anti-freeze.

More antifreeze genes make more antifreeze


Their tandem arrangement tells us there was another mutational network involved that duplicates individual and blocks of genes.

Mutation is the inventor.

We live in a world of mistakes, generated by chance.

Genetic mutations occur at random. The genes are changed without regard to potential consequences.

The fate of the mutation depends on external circumstances.

Natural selection dictates those external circumstances.


Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term “natural selection”, contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not.

If the mutation is beneficial to the organism, they will be in a better position to pass on their genes. The Antarctic eelpout is a good example,



Charles Robert Darwin FRS FRGS FLS FZS (12 February 1809 – 19 April 1882) was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution.

How and why did the Antarctic get so cold?

The answer involves tectonics

Tectonics are the processes that control the structure and properties of the Earth’s crust and its evolution through time. These include the processes of mountain building, the growth and behaviour of the strong, old cores of continents known as cratons, and the ways in which the relatively rigid plates that constitute the Earth’s outer shell interact with each other. Tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population.

Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles is essential to geomorphologists to explain erosion patterns and other Earth surface features.


Plate tectonics is the study of the lithosphere, the outer portion of the Earth consisting of the crust and part of the upper mantle. The lithosphere is divided into about a dozen large plates which move and interact with one another to create earthquakes, mountain ranges, volcanic activity, ocean trenches and many other features. Continents and ocean basins are moved and changed in shape as a result of these plate movements.



The sequence of maps above shows how a large supercontinent known as Pangaea was fragmented into several pieces, each being part of a mobile plate of the lithosphere. The fragments occurred just like a plate falling onto a hard surface.

These pieces were to become Earth’s current continents. The time sequence shown through the maps traces the paths of the continents to their current positions.

In the early 1900s, Alfred Wegener proposed the idea of Continental Drift. His ideas centred around continents moving across the face of the Earth. The idea was not quite correct – compared to the plate tectonics theory of today – but his thinking was on the proper track.



Alfred Lothar Wegener (1 November 1880 – November 1930) was a German polar researcher, geophysicist and meteorologist.

What determined the size, shape and speed of these plates?

The seas and continents sit on the tectonic plates that move around the globe very slowly.


The collision of the Indian subcontinent triggered global cooling and glaciation of the Antarctic. The separation of South America and Antarctic isolated the Southern Ocean led to cooler currents circulating the continent.

Why did the plates move in the way they did?


Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction, or one plate moving under another, carries the lower one down into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the lithosphere remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories, since disproven, proposed gradual shrinking (contraction) or gradual expansion of the globe.

Tectonic plates are able to move because the Earth’s lithosphere has greater mechanical strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection; that is, the slow creeping motion of Earth’s solid mantle. Plate movement is thought to be driven by a combination of the motion of the seafloor away from spreading ridges due to variations in topography (the ridge is a topographic high) and density changes in the crust (density increases as newly formed crust cools and moves away from the ridge). At subduction zones the relatively cold, dense oceanic crust is “pulled” or sinks down into the mantle over the downward convecting limb of a mantle cell. Another explanation lies in the different forces generated by tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.



Most geologists agree that plate movement is the result of the convective circulation of Earth’s heated interior. The heat source for convection is thought to be the decay of radioactive elements in the mantle. How this convection propels the plates is poorly understood.

In the western Pacific Ocean, the subduction of old dense oceanic crust may be self-propelled. The weight of the subducted slab may drag the rest of the plate toward the trench, a process known as slab pull, much as a tablecloth will pull itself off a table if more than half of the cloth is draped over the table’s edge.

Some geologists argue that the westward drift of North America and eastward drift of Europe and Africa may be due to push at the spreading ridge (the Mid-Atlantic Ridge), known as ridge push, in the Atlantic Ocean. This push is caused by gravitational force, and it exists because the ridge occurs at a higher elevation than the rest of the ocean floor. As rocks near the ridge cool, they become denser, and gravity pulls them away from the ridge. As a result, new magma is allowed to well upward from the underlying hot mantle.

Hot mantle that spreads out laterally beneath the ridges or at hotspots may speed up or slow down the plates, a force known as mantle drag. However, the mantle flow pattern at depth does not appear to be reflected in the surface movements of the plates.

Circulation in the mantle occurs by thermal convection, whereby warm buoyant material rises and cool dense material sinks. Convection is possible even though the mantle is solid; it occurs by solid-state creep, analogous to the slow downhill movement of valley glaciers. Materials can flow in this fashion if they are close to their melting temperatures.

Several different models of mantle convection have been proposed. The simplest, called whole mantle convection, describes the presence of several large cells that rise from the core-mantle boundary beneath oceanic ridges and begin their descent to that boundary at subduction zones. Some geophysicists argue for layered mantle convection, suggesting that more vigorous convection in the upper mantle is decoupled from that in the lower mantle. This model requires that the boundary between the upper and lower mantle is coincident with a change in composition. A third model, known as the mantle plume model, suggests that upwelling is focused in plumes that ascend from the core-mantle boundary, whereas diffuse return flow is accomplished by subduction zones, which, according to this model, extend to the core-mantle boundary.

The smaller plates moved more quicky and slammed into the other plates. The Indian plate moved more quickly because it is smaller.


The Himalayan range is one of the youngest mountain ranges on the planet and consists mostly of uplifted sedimentary and metamorphic rock. According to the modern theory of plate tectonics, its formation is a result of a continental collision along the convergent boundary between the Indo-Australian Plate and the Eurasian Plate. The Arakan Yoma highlands in Myanmar and the Andaman and Nicobar Islands in the Bay of Bengal were also formed as a result of this collision.

During the Upper Cretaceous, about 70 million years ago, the north-moving Indo-Australian Plate (which has subsequently broken into the Indian Plate and the Australian Plate) was moving at about 15 cm per year. About 50 million years ago this fast-moving Indo-Australian Plate had completely closed the Tethys Ocean, the existence of which has been determined by sedimentary rocks settled on the ocean floor and the volcanoes that fringed its edges. Since both plates were composed of low-density continental crust, they were thrust faulted and folded into mountain ranges rather than subducting into the mantle along an oceanic trench. An often-cited fact used to illustrate this process is that the summit of Mount Everest is made of marine limestone from this ancient ocean.

Today, the Indian plate continues to be driven horizontally at the Tibetan Plateau, which forces the plateau to continue to move upwards. The Indian plate is still moving at 67 mm per year, and over the next 10 million years it will travel about 1,500 km into Asia. About 20 mm per year of the India-Asia convergence is absorbed by thrusting along the Himalaya southern front. This leads to the Himalayas rising by about 5 mm per year, making them geologically active. The movement of the Indian plate into the Asian plate also makes this region seismically active, leading to earthquakes from time to time.


The 6,000-kilometre-plus journey of the India landmass (Indian Plate) before its collision with Asia (Eurasian Plate) about 40 to 50 million years ago.

The size, shape and speed of the tectonic plates is a matter of chance.

Chance invents, and the fate of that invention depends upon circumstances shaped by chance.

DNA is the inventor and the spread is determined by external circumstances. A personal example is my identical twin aunts. One of them developed dementia and the other didn’t. Why did that happen?

Blind chance is the origin of all the diversity, beauty etc. in the living world. However, we don’t live on the best of all possible worlds.

Shatters the belief in cause and effect.

Modern theologians aren’t happy. They think chance puts God out of a job.

God and chance


“It is not necessary for chance to rule in order to supplant God. Indeed, chance requires little authority at all if it is to depose God; all it needs to do the job is to exist. The mere existence of chance is enough to rip God from his cosmic throne. Chance does not need to rule; it does not need to be sovereign. If it exists as a mere impotent, humble servant, it leaves God not only out of date, but out of a job.”


Robert Charles Sproul (February 13, 1939 – December 14, 2017) was an American Reformed theologian and ordained pastor in the Presbyterian Church in America.

If we can’t turn to theologians, who do we turn to when considering change and its complications.

Professor Carroll suggests turning to certain authors (e.g. Kurt Vonnegut), scientists, humanists and comedians (Ricky Gervais and Eric Idle).


Kurt Vonnegut Jr (November 11, 1922 – April 11, 2007) was an American writer. In a career spanning over 50 years, Vonnegut published fourteen novels, three short story collections, five plays, and five works of nonfiction, with further collections being published after his death.


Vonnegut wrote a lot about our accident driven world and our struggle for meaning.


The novel, published in 1976, is presented as meditation on death, and on Vonnegut’s relationship with his sister Alice. As the author explains in an extended prologue, his sister died of cancer in 1958, a mere two days after her husband had also died in a train accident.

48 people died in the train accident including the author’s brother-in-law

The author and his brother went to visit Alice on what turned out to be her last day and tried to concoct lots of weird scenarios of why her husband wasn’t present so she wouldn’t worry about her four children.

However, Alice already knew because a fellow patient had told her about the accident




Vonnegut wrote

“(H)ers would have been an unremarkable death statistically, if it were not for one detail, which is this: Her healthy husband, James Carmalt Adams, the editor of a trade journal for purchasing agents, which he put together in a cubicle on Wall Street, had died two mornings before – on the ‘Brokers’ Special’, the only train in American railroading history to hurl itself off an open drawbridge. Think of that. This really happened.”

“Since Alice had never received any religious instruction, and since she had led a blameless life, she never thought of her awful luck as being anything but accidents in a very busy place. Good for her.”

We are all here because of a series of accidents; cosmological, geological and biological accidents.

Scientists, humanists and comedians don’t believe something happens for a reason. What do these people have in common?



Ricky Dene Gervais (born 25 June 1961) is an English comedian, actor, writer, producer, and director.

He has said “It always comes back to us – why are we here? Well, we just happened to be here, we couldn’t choose it. We’re not special, we’re just lucky; and this is a holiday. We didn’t exist for 14 and a half billion years. Then we got 80 or 90 years if we’re lucky, and then we will never exist again. So we should make the most of it.”



Eric Idle (born 29 March 1943) is an English actor, comedian, author and musician. Idle is a former member of the British surreal comedy group Monty Python, a member of the parody rock band The Rutles, and the writer of the music and lyrics for the Broadway musical Spamalot (based on Monty Python and the Holy Grail).

Humans do struggle when bad things happen, but https://en.wikipedia.org/wiki/Always_Look_on_the_Bright_Side_of_Life



The book

A Series of Fortunate events


Why is the world the way it is? How did we get here? Does everything happen for a reason or are some things left to chance? Philosophers and theologians have pondered these questions for millennia, but startling scientific discoveries over the past half century are revealing that we live in a world driven by chance. A Series of Fortunate Events tells the story of the awesome power of chance and how it is the surprising source of all the beauty and diversity in the living world.

Like every other species, we humans are here by accident. But it is shocking just how many things—any of which might never have occurred—had to happen in certain ways for any of us to exist. From an extremely improbable asteroid impact, to the wild gyrations of the Ice Age, to invisible accidents in our parents’ gonads, we are all here through an astonishing series of fortunate events. And chance continues to reign every day over the razor-thin line between our life and death.

This is a relatively small book about a really big idea. It is also a spirited tale. Drawing inspiration from Monty Python, Kurt Vonnegut, and other great thinkers, and crafted by one of today’s most accomplished science storytellers.


Acclaimed writer and biologist Sean B. Carroll narrates the rollicking, awe-inspiring story of the surprising power of chance in our lives and the world.

About the Author

Sean B. Carroll is an award-winning scientist, writer, educator, and film producer. He is Vice President for Science Education at the Howard Hughes Medical Institute and the Balo-Simon Chair of Biology at the University of Maryland. His books include The Serengeti Rules (Princeton), Brave Genius, and Remarkable Creatures, which was a finalist for the National Book Award. He lives in Chevy Chase, Maryland. Twitter @SeanBiolCarroll

Questions and answers

1) How could an asteroid cause heating but then cause cold to happen by blocking the Sun?

The asteroid entered the Earth’s atmosphere at a great speed, hit the Earth and caused a great deal of material to be blasted into the sky.

The heating effect of the asteroid entering the atmosphere and the material falling back down after the asteroid impact caused the heating effect due to friction.

The resultant vapour plume contained sulphur dioxide and carbon dioxide as well as water vapour and produced a reflecting layer for sunlight. Wildfires produced a lot of soot, which along with material from the blast that didn’t return to Earth blocked the sunlight.

Sunlight was drastically reduced for up to 30 years. The thermal pulse at the start was very short lived. Large animals would have found it difficult to breathe. This and the eventual loss of sunlight caused lots of plants became extinct.

The oceans got into bad shape as indicated by the drop in the number of forams. The survivors were small burrowing, primitive mammals, burrowing snakes and shore birds.

2) Can the asteroid movement be modelled (this could prove for possible future events). Isn’t there a random chance?

What if we can’t predict because of our knowledge of the system.


something that might possibly happen in the future, usually causing problems or making further arrangements necessary

Some events are determined by previous events. Lots and lots of contingencies. So, chances can become contingencies for future events.

The asteroid was the contingency for the rise of mammals.

If we had known the positions of all the objects orbiting in the Solar System could we predict if, when and where they will impact on the Earth.

The science isn’t there yet. We still get surprised by the occasional meteorite

We would also need a lot more information to predict the biological effects of such an incident.

Contingency is a relatively accommodating definition of change. An event that is so rare and infrequent. So unpredictable but whose consequences are so important. Just seeing how the course of life has been buffeted by these large scale and unpredictable events.

Scientists always want to be able to model these things better and be able to predict the outcomes better. They are dependent on empirical data to do that and we are still learning the empirical facts around things like mass extinctions.

Random chance does seem like the roll of a dice or a flip of a coin where the outcome is not connected to any previous rolls. Mutation does really work like this. The random changes in sperm and/or egg is completely unpredictable. Also unpredictable is the chance the winning sperm and/or egg will produce a new offspring because of fertilisation.

Compounding low probability events gives astronomical odds.

3) Do we worry too much about extinction?

Unfortunately, 94% of all life on Earth is human livestock and crops.

Only 4% are wild mammals.

Humans are stressing air, food, soil and ocean. Ecologists worry that the situation is not sustainable. We must be concerned about how far we have pushed wild nature.

4) How do we know for sure that the asteroid caused the extinction of the dinosaurs? Why not a series of volcanic explosions?

Professor Carroll is 90+% sure the extinction occurred. The fall out layer mentioned earlier persuades many people.

We understand the size and environmental impact of the asteroid.

The erupting volcanoes might have primed for life on Earth being more vulnerable to extinction.

Perhaps the asteroid itself could have led to the eruptions. This is being studied. So, we must be careful that we never say never.

However, the evidence for the asteroid impacting and the fall out layer is the most persuasive. It is consistent with the biological patterns that we see,

Professor Carroll didn’t want to dismiss the idea that there was some contribution by volcanic eruptions but the majority of scientists are persuaded that the asteroid was the cause.

5) Where does al this leave determinism and free-will?

Humans believe that there are forces that govern their individual lives. These things determine who we are at the moment of conception. They determine how our species got here.

For Charles Darwin, Natural Selection was the big thing. He tried to deal with where the variation came from. He realised that there was something accidental but it wasn’t his time. The knowledge wasn’t there yet.



Darwin, c. 1854, when he was preparing “On the Origin of Species” for publication

Charles Robert Darwin FRS FRGS FLS FZS (12 February 1809 – 19 April 1882) was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution.

Natural selection has shaped peoples’ ideas of life on Earth and a lot of scientists still think of it as extremely important, but chance is also important. Chance dissolves a lot of prior ideas about cause and effect on the planet.

People have free will to ignore Professor Carroll’s talk.

There is a hell of a lot of contingencies in the natural world.

The majority of Americans still think things happen for a reason but the more we know the more it is apparent that nothing is in charge. There is too much randomness.

6) Where does this leave God?

All scientists can do is bring the evidence to the table and let people decide.

7) Why does life end up in the most extreme conditions?

By accident. An organism may be born with certain mutations in their DNA, like the eel pout, which allows them to move into an environment where they can survive where other organisms can’t.

Single celled organisms have lots of “machinery” for dealing with adverse conditions. In a previous blog I wrote about the fact that some bacteria have evolved to “eat” certain plastics.

Astrobiologists wouldn’t be surprised to find single celled organisms outside of the Earth, replicating molecules inside a bubble.

An organism’s random mutations might allow it to live somewhere the others can’t.

8) Are humans random or interfering?

About 12000 years ago humans were insignificant. There were more bison then than there were humans.

It is weird that one species has had such an effect on the environment. We are a geological force of nature. We are the modern asteroid.

We have creative and technological prowess and we affect the rest of the planet.

We are interfering with nature’s randomness and we are reducing some of this randomness. We are the cause of the shrinking of so many species populations

The number of interesting mutations is decreasing and future biological diversity is restricted.

Hopefully we are smart enough to change our ways. We are removing whole species of organisms with monoculture.

Knowledge is power.

9) We already know the history of the asteroid why didn’t Professor Carroll start his talk about the Big Bang.

Too remote

My view

I don’t usually voice an opinion on my blogs but I felt this needed it.

I am a practising Roman Catholic but I am also a physicist. It may surprise you to know that I don’t have any problems with either.

Problems arise with some religious people who take their holy books literally. To me the bible (Old and New Testaments) is a guide to life. If God did create the Earth in six days whose to say his/her day wasn’t a different length to ours.

My view is that God was there at the start of the Universe and let things progress in their own merry way. It may surprise people to know that the Vatican has an astronomy department and Catholic priests have been involved in scientific discovery.


The one that is linked to this talk is Gregor Mendel



Gregor Johann Mendel (20 July 1822[3] – 6 January 1884) was a scientist, Augustinian friar and abbot of St. Thomas’ Abbey in Brno, Margraviate of Moravia. He gained posthumous recognition as the founder of the modern science of genetics. His pea plant experiments conducted between 1856 and 1863 established many of the rules of heredity, now referred to as the laws of Mendelian inheritance. The profound significance of Mendel’s work was not recognized until the turn of the 20th century and provided the means of showing how Darwin’s natural selection could come about.

My own hero, as physicist, is Georges Lemaître.



Georges Henri Joseph Édouard Lemaître, RAS Associate (17 July 1894 – 20 June 1966) was a Belgian Catholic priest, mathematician, astronomer, and professor of physics at the Catholic University of Louvain. He was the first to identify that the recession of nearby galaxies can be explained by a theory of an expanding universe, which was observationally confirmed soon afterwards by Edwin Hubble. He was the first to derive what used to be known as “Hubble’s law”, but since 2018 has officially been renamed the Hubble–Lemaître law, and made the first estimation of what is still called the Hubble constant, which he published in 1927, two years before Hubble’s article. Lemaître also proposed what later became known as the “Big Bang theory” of the origin of the universe, initially calling it the “hypothesis of the primeval atom”.

Another of my science heroes was Michael Faraday. Not a Catholic but a devout Christian.


Michael Faraday FRS (22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic induction, diamagnetism and electrolysis.


We humans want it both ways. We want free will but we expected God to pick up the pieces when things go wrong.

If God does intervene it will because nobody will be worse off if he/she does.

It always makes me cross when some people say “If there were a God, blah, blah wouldn’t happen” but we humans are in a position to solve things.

For instance, we choose to go to war, live in regions where there is a good chance of an earthquake, floods etc.

We choose to waste money on weapons when we could be spending the money on research to get rid of cancer and deadly diseases. There is enough money in this world that nobody has to be poor.

We only have a short period of time until we ruin this beautiful world permanently. My husband and I are a little grateful that we did not have children. It is the children who will have to suffer the consequences. But my heart goes out to all my ex-students who are now parents.

I also believe that God didn’t instigate religion. I like being a Catholic because it brings me comfort and peace and improves my relationships with my fellow humans but that doesn’t mean I am any more right than my Jewish, Muslim, Hindu or Buddhist fellow humans and I don’t believe for a minute that Jesus set out to create a new religion from the Jewish faith. He was trying to show us a better path for our lives, just like Mohammed, Moses and Siddhartha Gotama (and the originators of other religions).

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