Clube and Napier's Coherent Catastrophism, and Wikipedia
My new book is founded on Clube and Napier's coherent catastrophism. They are both formerly Professors of Edinburgh (where I am now - complete coincidence) and Oxford. Bill Napier is an astronomer specialising in cometary science while Victor Clube is an astrophysicist. They first published on this subject, to the best of my knowledge, in 1979. But it was not until the early 1980s that they developed their 'terrestrial theory of catastrophism'. It was later, in the early 1990s I think, that their collaborator, Duncan Steel, coined the term 'coherent catastrophism', and that's how their theory is now popularly known. Together with David Asher and Mark Bailey, these five scientists have pioneered research into their alternative view of cosmic catastrophism on Earth - one based on comets rather than asteroids.
The evidence they have accumulated is compelling, but controversial. I give some of the reasons for the resistance to their ideas in Prehistory Decoded. But this is a hazy topic, and I really hope one of them writes about this soon. It almost feels like a conspiracy. It would be great to hear about their views on this. Their early thoughts are contained in the excellent books 'The Cosmic Serpent' and 'Cosmic Winter', but these books have become quite rare and very expensive.
Despite the importance of this topic, and the solid evidence that supports it, you won't find anything on Wikipedia about 'coherent catastrophism'. This is a serious anomaly, as coherent catastrophism is clearly one of the most important issues facing humanity. After writing my 'Fox' paper, I tried to create a Wikipedia article on coherent catastrophism, but it was repeatedly deleted by Wikipedia's established editors. They know all the tricks. Today, you can only find these old articles on 'deletedwiki'.
I think this needs to change. I invite anyone reading this to become a Wikipedia editor and to try and create a balanced wiki page on 'coherent catastrophism'. You will also notice the bias on Wikipedia's pages for the Younger Dryas impact event, Gobekli Tepe, and all other matters relating to the topics in my book. Again, this needs to be redressed.
The term 'coherent' is used to distinguish this form of cosmic collision process from the randomly-timed collisions expected with asteroids from the asteroid belt, a diffuse ring of rock-metal debris that orbits between Mars and Jupiter. So 'coherent' specifically refers to collisions with cometary debris. In this context, the term 'coherent' implies collision events are correlated in time - they happen in bursts. But the timescale for these bursts is not specified, because there are many different timescales to consider.
Specifically, there can be multiple collisions within seconds of each other as Earth collides with a swarm of debris. This could happen multiple times within a single day - it all depends how fragmented the comet debris is.
Moreover, if Earth collides with some debris, the chance of a collision 33 years later is increased. This number arises because the orbital period of the main sub-stream, which is thought to orbit with comet Encke, is 3.3 years. Therefore, Encke needs to complete 10 orbits before coming back to approximately the same point of intersection with Earth's orbit.
However, because the Taurids are so old and fragmented, and because of the eccentric shape of the Taurid meteor stream, apsidal precession (this is explained in Prehistory Decoded) causes the risk of collision to extend for a period of several hundred years. This is quite complicated to explain, but essentially Earth's orbit intersects a Taurid-like orbit twice within a few hundred years - once with the descending stream and once again, a few hundred years later, with the ascending stream on the opposite side of our orbit around the sun. This pattern repeats every 3000 years or so, because the period for a complete cycle of apsidal precession for Encke-like objects is around 6000 years.
But, when a large comet, like the progenitor of Encke for example, decays it can take several 10s of thousands of years for its debris to clear. So there is a correlated risk on this timescale too.
Finally, Clube and Napier have suggested another, even longer, timescale over which collisions could be correlated in time. The solar system oscillates 'up and down' through the plane of the galactic disk every 30 million years. They suggest our passage through the mid-plane of the galactic disk disturbs comets orbiting in the scattered disk and Oort cloud, which then causes the Centaur population of comets, which orbit between Jupiter and Neptune, to be replenished. And this is the pool of giant comets which can, eventually, threaten Earth. A Centaur can be slowed sufficiently by a close approach to Jupiter that it can enter, and become trapped in, the inner solar system, where it will then decay and threaten Earth. In other words, there is an enhanced risk on the timescale of millions of years, every 30 million years or so. They suggest this might be responsible for the pattern of major extinctions and glacial ages seen on geological timescales. Of course, this idea is disputed by many other scientists, but it makes perfect sense.
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