Throwing Planets Around!
Paul Dunbavin (2020)
Summary
Between 1999 and revised up to 2018 a series of papers proposing the Planet-Z Hypothesis
were published by a group of physicists and astronomers, including the eminent astronomer
Willy Woelfli; these would seek to revise and augment the ideas of Immanuel Velikovsky with
more realistic physics. This article seeks to constructively compare and contrast the strands
of enquiry to date.
The Planet Z hypothesis is granted a greater degree of scientific credibility and exposure than it might
otherwise attain, due to the eminence of the authors and its presence on the Cornell University online
archive. Physics professors can perhaps cite Velikovsky without risking credibility – but no-one else
could expect to have similar work published on such prestigious platforms.
The co-authors of the series of papers are Professor emeritus Dr Willy Woelfli and Professor Dr
Walter Baltensperger; together with Robert Nufer, who describes himself as an amateur astronomer
with a particular interest in comets. Here, to avoid repetition, I shall refer to them as ‘the authors’, or
‘the co-authors’ and cite the papers either collectively or by individual publication date. The
background of the three authors is described in their own papers listed below (Robert Nufer’s
astronomy website is recommended reading). [1]
To attempt a summary of the theories, with apologies for brevity, would be as follows. The 1999
paper (later revised for v1 in 2018) introduces the concept of a periodic close approach by an
additional planet as a possible explanation for Earth’s climatic changes in the past few million years.
This idea was further expanded in the 2002 paper by the same authors. The model simulates a planet
in an eccentric Earth-crossing orbit as a principal cause of the Pleistocene ice ages between 3.5m
years ago and its (apparent) end 11.5k years ago; this planet they term ‘Z’ to substitute for
Velikovsky’s rogue ‘Venus’. The highly eccentric orbit of this hypothetical body allowed several
close approaches during the Pleistocene Ice Age; during these encounters, especially during its final
pass, the tidal forces deformed the Earth resulting in a pole shift that dragged the North Pole away
from Greenland to its present location. The final close-encounter resulted in the break-up of Z which
no longer exists. The age of ice is therefore considered to be over and we are back to the stable
conditions that existed back in the Miocene epoch.
The hypothesis stresses that the Earth’s obliquity was scarcely affected by the Pleistocene encounters
and that the geographical pole shift was caused by a tidal bulge resultant from the close approach of
Z, which altered the rotational balance. They then proceed to calculate the mass, structure and orbital
properties of the transitory planet in order to cause the required tidal effects. In gradualist geological
theories the trigger for ice ages is the drift of a continent over one or both of the poles; in a
catastrophic event such a transition could take place more rapidly due to a pole-shift.
The co-authors comment on the doubtful physics underlying Velikovsky’s original astronomy. Much
stress is also placed upon his letters to Albert Einstein and the physicist’s reply: “Catastrophes yes,
Venus – no!” What a marketing coup that was for an author! But why did the co-authors find it
necessary to commence from a base of 1950’s science? [2]
The computer simulation reveals that the required tidal effects demand an extremely close approach
by a planet with at least the mass of Mars (therefore truly a planet and not a comet). The repeated
visits of the disintegrating Z to the inner solar system would have left a debris trail along its orbit,
thereby triggering a cooling effect, due to the dust veil in space and in our atmosphere. Another
feature of the model is that the close-approaches of Z and its dust veil are considered more influential
upon ice age climate than the Milankovich effect. Since all trace of Z has now gone (save perhaps for
periodic meteor showers) then it must have been either ejected or dissolved, or the fragments fallen
into the sun. Such a break-up demands that in its final approach Z must have entered within the
Earth’s Roche limit – very close indeed!
The authors then offer a discussion of which facts become plausible or explainable by their model.
The most obvious of these is the survival of mammoths in Siberia and the evidence that Siberia was
never covered by an ice cap; Lake Baikal did not freeze and its unique fauna survives; the Himalayas
were not ice-domed as were the Alps. These anomalies are not explainable by gradualist geological
theories. The semi-tropical conditions at mid-latitudes during the ‘interglacials’ are also glossed-over
in gradualist theories, as are the so-called ‘Heinrich events’ when the polar sea-ice apparently brokeup. The co-authors believe that their modelling can also explain such anomalies; it is only the
conclusion of these climate fluctuations that has allowed human civilization to flourish.
The 2007 paper builds upon the earlier studies with more concise information and mathematics. A
further summary of this additional detail would be as follows:
The eccentric orbit of Planet Z caused it to become extremely hot due to ‘tidal work and solar
radiation’. The final close encounter produced a ‘stretching deformation’ of the Earth that was the
ultimate trigger for pole-shift. The hypothesis suggests that the survival of dwarf mammoths on
Wrangel Island indicates a change of latitude and adds further comment that the Milankovitch effect
‘cannot be understood’ without assuming a formerly lower-latitude for Siberia; also that it cannot
explain why the same secular orbital factors did not apply back in the Miocene.
Planet Z must have been breaking-up before the final encounter, but the computer simulation, they
admit, does not allow for this shedding of mass. However they conclude: ‘…that Z had at least 1/10 of
the mass of Earth…’ and remark: ‘For example Z might have been a moon of Jupiter which got loose’
and ‘Clearly, Z had to be hot and emitting material already before the polar shift’. The authors then
consider the lifetime of a cloud of particles from the disintegrating Z:
‘The orbits of the individual particles will be spread over rather vast space so that initially particles
do not collide. Their lifetime is limited by Poynting-Robertson drag … valid for circular motion’ [see
note 3 below].
They argue for traces of the dust cloud in ice-cores and that:
‘A first version of this paper was written under the impression, that a terrestrial origin of the
inclusions in bore ice had been demonstrated’.
However this constraint only applies to the dust rather than any larger fragments residual from the
final break-up. The final pass of the disintegrating Mars-sized Z was described in the 2002 paper:
‘We expect that the peak tidal force has to be about an order of magnitude larger [than previous
encounters]… this brings the closest distance between the centres of Earth and Z into the range of
12,000 to 15,000 km. As a result, Z enters the Roche limit of Earth’.
Regarding the end of the Pleistocene they add:
‘We just note here that the last rapid increase of the temperature recorded in the polar ice data
occurred at 11 500 ± 65 yr BP…Thus, it appears that the Younger Dryas, which begins at 12 700 ±
100 yr BP is younger than the polar shift event’.
A further paper in 2010 was devoted to the folk-memory of these events in various ancient sources.
These references were added because the earlier papers gave rise to comment that Z should be
remembered in the old traditions. Here they cite Chinese myths of ‘persistent daylight’ such that
people were unable to sleep; and the myth of twin suns in the sky. This glow is attributed to the ‘hot’
Z, which they equate with the Typhon comet as recalled by Pliny and other classical writers. A
comparable legend from the Ojibwa of North America is similarly advanced.
Next they cite Herodotus who describes a memory of the sun rising in the west and setting in the east,
as given to him by the Egyptian Priests of Hephaestus; together with their calculation based on a
priest-list that the age of Egyptian civilization stretched back as much as 11,340 years. The authors
cite Herodotus, as did Velikovsky before them, that during this period the sun reversed its positions of
rising and setting twice without detriment to life in Egypt. The late Peter Warlow in The Reversing
Earth would try to explain this by the Earth turning completely upside down on its axis due to a
similar tidal influence. [3] The authors prefer to explain it as a memory of Z in the sky rather than of
the sun.
The authors remark on the Biblical references in Joshua to the sun standing still in the sky; and the
close pass of a fragment of the lost Z as described in the Book of Ezekiel (594 BC – hence long after
the final break-up). Another Biblical citation comes from the Book of Revelation; and a related
quotation from Josephus regarding a time of ancient cataclysm. Reference is also made to the events
of Exodus as a memory of relevant events, but the seven-year famine of Joseph is not cited.
Next they discuss the Egyptian Papyrus Ipuwer (First Intermediate Period) as a memory of the
terminal-Pleistocene pole shift. They would view the papyrus as a recollection of various catastrophes
from much earlier times rather than a reference to contemporary events.
Plato’s Critias and Timaeus are extensively quoted. Here the authors cite the date given by Plato
(Solon) again based on a chronology supplied by Egyptian priests. Therefore, they follow the literal
dating assumption that he describes events at the end of the Pleistocene c.12 000 years BP; and
therefore that an organized state must have existed both in Egypt and Greece at that date
Further memories of the Flood, the authors continue, are to be found in the Epic of Gilgamesh;
preferred here to a discussion of the Biblical Noah. This event they attribute to the tidal forces
produced by the passing planet. The passage of Z is more directly recalled in the words of Ovid’s
Metamorphoses. This recalls the comet Phaethon, perhaps a fragment of Z, which caused burning air
and deserts in the Egyptian Delta and elsewhere. The authors offer a table showing the changes of
latitude required to explain these various recollections, based on the pole shift that they propose.
Of crucial importance is the apparent memory of a change to the number of days in the year from 360
days to our present experience. Here the authors draw again on Velikovsky and state:
“Conservation of angular momentum grants that the direction of the Earth’s axis in space cannot
change appreciably during a catastrophic event”.
The same constraint therefore applies to the diurnal rotation and they take Velikovsky to task on his
physics; he cited Indian, Babylonian, Mayan, Chinese and Egyptian memories of a former 360-day
year. The authors prefer to say:
“What would be modified is Earth’s orbital semi-axis and period rather than the rotation frequency of
the globe.”
In other words they suggest a change to the Earth’s orbit rather than to the length of day.
Overall, computer simulations apart, the series of papers are not unlike many other studies that have
been put out by adherents of Velikovsky and which usually receive the accolade of pseudo-science. It
is only the mathematical modelling and the academic credentials of the authors that allow them to
escape that categorisation. One has to doubt whether anyone lacking such status could achieve
publication of Velikovsky-related theories on such prestigious academic platforms.
The above summary should serve as only an introduction, with apologies again for any omissions or
abbreviation due to brevity; interested researchers should read the original papers in detail and form
their own opinions.
Areas of General Agreement with the Z-hypothesis
As one would expect of a group of physicists, their physics is impeccable. Many enthusiasts and
commentators on the subject of catastrophism, Atlantis, etc, may make loose references to pole-shifts
and axis tilts without understanding that these are not the same thing; or that a vast external force
must be applied to the Earth to bring about the latter. The co-authors do not make these errors.
However, it is not clear whether the orbital mechanics used in their computer simulation have been
peer reviewed.
The 2002 paper shows an illustration of the pole shift as the North Pole spirals away from its former
position over Greenland to its present location. This shift, they propose, was the terminal-Pleistocene
event. The suggested spiralling motion follows the mechanism of the Chandler wobble, but is not
quite complete, as will be discussed below. Overall the computer model predicts a shift of the North
Pole away from Greenland by perhaps as much as 17-18⁰ – but leaving open a lesser magnitude. Note
that this would still allow the South Pole to lie within East Antarctica.
The proposed close approach and tidal bulge, rather than an impact scenario, would explain the lack
of any physical evidence of an impact at the end of the ice-age (There is no known ‘crater’). It offers a
mechanism that could change the geoid of the planet affecting rotational balance – thus triggering a
pole shift – in the absence of hard evidence. However there remain other factors that it could not
explain; both cited within the papers themselves and elsewhere.
The authors are clear in their rejection of a general rearrangement of the planetary orbits and conclude
that Earth’s orbit could be only marginally affected, as would the obliquity in space. The focus
therefore falls upon tidal forces that could cause a geographical pole shift and the effect on the
Pleistocene climate due to the periodic returns of Z and its dust veil.
Divergence from the Z-hypothesis
I shall try here to be constructive in analysis of the hypothesis and to avoid purely negative criticism.
Where the authors depart from their excellence in physics and astronomy then they stand on less firm
ground. Their knowledge of climate and sea-level research is less well demonstrated in the papers.
Another example would be their approach to Egyptology. One doubts whether any Egyptologist
would consider a civilisation with written historical records, in Egypt, or Greece, as far back as
12,500 years ago. At that era the Nile valley was a swamp and the hunter-gatherers who would
become Egyptians were able to live all over the still-green Sahara.
The Z hypothesis takes the literal dates supplied by Plato and Herodotus for the antiquity of Egyptian
civilization and notes their close correspondence with the date of the Pleistocene-Holocene transition.
This apparent correspondence of the terminal ice-age event and the pseudo-Egyptian chronology was
a subject explored in the present author’s earlier books. It can be explained by reference to the
Egyptian belief, found in Manetho, that the antiquity of their state extended back 36,525 years with
the dynasties of kings being preceded by a long list of demi-gods and god-kings. The Egyptians
priests also made the same error as nineteenth-century Egyptologists in treating all the reigns as
consecutive, whereas many kings ruled in parallel in different regions. The fact that we find the long
chronology recorded in two independent sources dating from c.600 BC (Solon and Herodotus) shows
us that this error is ancient.
The confusion in the position of sunrise and sunset is also explainable by standard Egyptology. The
Egyptian civil calendar was not adjusted by an epagominal day (equivalent to Julio-Gregorian 29
February) and therefore wandered through the seasons every 1,460 Julian years (the Sothic Cycle).
Thus it sometimes had summer occurring in ‘winter’ months and vice-versa. This would indeed have
cycled twice during the period of Dynastic Egypt from the predynastic up to the date of Herodotus. It
therefore seems likely that there was a misunderstanding somewhere between the priests trying to
explain this via an interpreter to their visitor, and in the understanding by Herodotus of what was
being described to him. The simplest explanation is always the best and a simple mistranslation is far
more likely than an astronomical cataclysm.
The problem of a former 360-day year is another fragile point in the Z-hypothesis. In the 2010 paper
this world-wide calendar device is employed as a memory of the terminal-Pleistocene changes.
However, the Indian and the Mayan eras, when these changes supposedly occurred, are placed at 3102
BC and 3114 BC in the respective mythologies. This would place it in the mid-Holocene rather than
at the Pleistocene-Holocene transition. Moreover, it cannot be employed as a memory of a change to
Earth’s orbit when the conclusion from the authors’ own simulation is that Earth’s orbit was ‘only
marginally perturbed’. Alternatively, a real modification to the length-of-day would require a
significant change of angular momentum, which the authors agree, could not occur via this
mechanism. The presence of a belief in a former 360-day year, in distant and unrelated ancient
civilizations, must therefore remain an enigma that is not explained by this model.
The proposed pole shift itself is attributed to the mechanism of the Chandler wobble; being merely a
much larger manifestation of the tiny pole-shifts that modern geophysicists regularly monitor. It is
generally conceded that the cause of the modern wobble remains unknown and could therefore be a
vestige of an ancient event. Current geophysical theory suggests that the mechanism would not be a
neat spiral from former pole to new pole as shown in the authors’ illustration. Rather, the pole must
jump instantaneously to a new ‘excitation pole’ and the spiral wobble then commences; however as
the proposed Z passes-by and the location of the bulge progresses, then the axis would jump
repeatedly before the spiral completes. Only when the encounter was concluded would the wobble be
allowed to decay to rest. Moreover, the Earth has a second mode of wobble, which should also be
excited and would interfere with the Chandler wobble. A good mathematical explanation of the
required excitation mechanisms is given in Lambeck’s Geophysical Geodesy (pp 552-5). [4]
The co-authors say in the 2002/2018 paper: ‘Note that this model has only few free parameters’. This
is an admission that: although it may be demonstrable by modelling that a stray-planet in just the right
circumstances could cause the tidal effects (as they have defined them) it is all extremely unlikely. It
has to be just right; in just the right orbit and just the right size; and it has to be just the right
temperature to disintegrate and glow like a second sun. The hypothesis offers us a comforting view
that this unwelcome visitor, which caused the ice ages, is now gone for ever and will not trouble us
again. However, as the author’s themselves conclude: “On the other hand, it creates new problems
that deserve a more complete treatment in future studies”.
The notion that we are now safe from a recurrence of the Ice Age is premature. We see during the
Holocene a series of climate transitions and sea-level variations. There is a pattern of evidence across
various disciplines that points to a lesser climate change and sea-level event in the mid-Holocene,
during the late fourth millennium BC. In Europe, we also find transitions from one stable climate
regime to another (the pollen zones) just as was ongoing during the Ice Age. The mid-Holocene:
Atlantic to Sub-Boreal transition (known as Hypsithermal in North America) is the strongest of these
signals. While fluctuations of temperature could be explained by a dust veil, rapid transitions from
one stable regime to another cannot. These require further astronomical interventions similar to the
terminal Pleistocene event. It is not clear how the fragments of Z, returning to our vicinity, could
cause these unless they impacted; the fragments would not possess sufficient mass to pull a tidal bulge
as is proposed for the main event.
A Mars-sized planet, at the distance of the Moon would appear six-times as large in our sky. If it must
pass within 15,000 km of us in order to cause the required tidal effects then it would fill half the sky
[See Note 4]. Furthermore, not only would it raise a solid-tide and an oceanic tidal bulge, but surely, it
must also draw part of the atmosphere away into space? Noah, floating in his ark, would have no air
to breath; and above his head the sky would be filled by a huge red planet. In other regions the ocean
beds would be sucked dry and land at sea-level would be elevated temporarily into the stratosphere.
Strangely no memory of this is described in the various Flood myths and religious texts from around
the world; although we do find the myths of sky-gods, fiery dragons, second suns, etc; all of which
could be explained by less drastic comet sightings. Commonsense would suggest that Planet Z did not
happen, even though it remains a theoretical possibility that can be modelled in a computer.
A conundrum is that Z has to behave sometimes like a planet; sometimes like a comet. The authors
admit that they have not modelled the change in mass as the repeated returns of Z cause it to break
apart. It must retain the required mass to produce the solid tides; therefore, it must have a rocky, or
even an iron core just like the real Mars. However, it also has to break-up and disappear after repeated
encounters with both Earth and Sun. It should therefore have left a rocky asteroid belt, equivalent to
that between Mars and Jupiter, rather than just a comet-like tail of dust and gas. Surely at least a few
of these larger bodies should still be with us today? If Z is to be just a huge icy comet like, for
example a larger version of 95P/Chiron, then it could not possess the required gravity.
Another consideration is the equatorial bulge. The polar radius is 6,356km while the equatorial radius
is 6,378km; a difference of some 22km. For a postulated 18⁰ pole shift then the pole tide generated is
of the order of 6,500m. This is simply enormous – higher than the Alps. Nineteenth Century science
discussed this and shied away. The Z model, so the co-authors argue, was based on a loose 1000-day
period of relaxation within which the plastic-Earth would conform to the new ellipsoid. Geophysicists
cannot yet give us any certainty as to how long a relaxation of figure might actually take in such
hypothetical extreme circumstances. It should be apparent that during this transition the deep ocean
would spill-over continental interiors, not just the coastal zones. It would sweep away fragile lake
eco-systems such as Baikal, the survival of which the authors have already used to justify the former
position of the poles. We should be finding the bones of Pleistocene whales in the desert.
Many of the objections to Z could be removed if it is not required to return repeatedly and if it is not
employed as the principal cause of ice ages. The fundamental basis for ice-ages is the presence of a
frozen continent at one or both of the poles, together with the Milankovitch cycles due to secular
gravitational pull of the planets. These factors would be present regardless of additional interventions
from space. A single close passage by a massive body, originating from the outer solar system or
beyond, is more plausible. Also, the mass need not be just a planet or comet, if we allow the
possibility of mini-black-holes recently proposed by Scholz and Unwin. [5] There may be more than
one type of astronomical cause for past climate episodes and a Z-type body is just another to add to
the list.
Causes of ice ages apart, as to whether the tidal bulge mechanism is the right one to explain the
terminal ice-age event depends upon what it is required to explain. If it is to trigger solely a pole-shift
then it remains a candidate; however if it must also explain a change of obliquity or the length of day,
or a change to the orbit, then we must look for other ways to apply the necessary energy without
leaving hard evidence.
In their closure summary (2007) the co-authors, as is usual, suggest the need for further study. In their
own words: ‘In the case that these contradict the given estimates, they could primarily question this
particular scenario, rather than the evidence that a pole shift has occurred’.
So, we are in agreement that a pole shift occurred; the disagreement is: more than one and more than
one possible cause.
Notes and References
Note 1
This author’s own work on catastrophism, in parallel but slightly preceding the Z hypothesis (published 19952005 and 2017) has always avoided comparisons with Velikovsky. [6] Since reading his books in the 1960s –
long before I began any serious research into ancient catastrophism – I consciously avoided reading or citing
them in order not to become associated with his unique astronomy – but there is no escape from it. The Z
hypothesis was just one more strand of Velikovsky-like research to evade. It would have been better if the
authors of the Z-hypothesis had let it stand alone rather than citing Velikovsky in so many places, as I remain
unconvinced that he actually believed everything that he wrote. In this author’s books (1995-2017) a similar
pole shift mechanism based on the Earth’s wobble was explored primarily in support of a mid-Holocene event,
but also acknowledged the occurrence of a much larger event at the Pleistocene-Holocene boundary. A
discussion of alternative pole-shift mechanisms due to low-mass, high-energy impacts may be found at
https://www.academia.edu/94905856/Throwing_Planets_Around
Note 2
All comments here are based on the v1 versions of the subject papers available at arxiv.org. The older versions
on the Los Alamos website (lanl.gov) that are cited within the papers themselves and elsewhere could not be
obtained and have not been cited other than where the authors update their own thinking.
Note 3
An explanation of Poynting-Robertson drag may be found at:
https://academic.oup.com/mnras/article/460/1/802/2608912
Note 4
Earth's diameter is 12,742 km and the moon is 384,400 km distance; (30.168 diameters) The Roche limit for the
Earth-Moon system is approx: 18,470 km (1.45 diameters). The solid earth tide due to the pull of sun and moon
is of the order of 20 cm, and can exceed 30 cm.
Principal Sources Discussed
1999
W. Wölfli, W. Baltensperger (1999) A possible explanation for Earth’s climatic changes in the past few million
years, http://xxx.lanl.gov/abs/physics/9907033 [Link broken – see note 2 above]
W. Wölfli, W. Baltensperger, A possible explanation for Earth’s climatic changes in the past few million years,
Notas de Fisica, Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, CBPF-NF-031/99, (June 1999). More
recent version: http://arxiv.org/abs/astro-ph/9909464v1 [this link and the 2018 link go to the same page,
where a 2018 pdf is shown]
2002
W. Woelfli and W. Baltensperger (2002) An additional planet as a model for the Pleistocene Ice Age, CBPF,
Notas de Fısica 007/02 or http://arxiv.org/abs/physics/0204004; http://arxiv.org/abs/physics/0204004v1
2006
W. Woelfli and W. Baltensperger (2006) Arctic East Siberia had a lower latitude in the Pleistocene,
http://arxiv.org/abs/physics/0604029 or CBPF, Notas de F´ısica, NF-008/06, March 2006.
2007
W. Woelfli and W. Baltensperger (2007) On the change of latitude of Arctic East Siberia at the end of the
Pleistocene, http://arxiv.org/abs/0704.2489
2010
W. Woelfli and W. Baltensperger (2010 September 26) Traditions connected with the pole shift model of the
Pleistocene http://arxiv.org/abs/1009.5078v1
2018
R. Nufer, W. Baltensperger and W. Woelfli (2018 March 29) Long term behaviour of a hypothetical planet in a
highly eccentric orbit http://arxiv.org/abs/astro-ph/9909464; http://arxiv.org/abs/astro-ph/9909464v1
Other References
1. https://robertnufer.ch/
2. Palmer, Trevor (2018) Perilous Planet Earth Revisited, Chronology and Catastrophism Review 2018:2, 3-19
https://www.academia.edu/41250309/Perilous_Planet_Earth_Revisited_Chronology_and_Catastrophism_Revie
w_2018_2_pp._3-19
3. Warlow, Peter (1982) The Reversing Earth ISBN 10: 0460044788 - ISBN 13: 9780460044783 - Weidenfeld
& Nicolson, London.
4. Lambeck, Kurt (1988) Geophysical Geodesy: The Slow Deformations of the Earth. Clarendon Press, Oxford
ISBN: 0-19-854438-3.
5. Scholz, Jakob and Unwin, James (2019). What if Planet 9 is a primordial Black Hole?
https://arxiv.org/pdf/1909.11090.pdf
6. Dunbavin, Paul (2005) Under Ancient Skies, Ancient Astronomy and Terrestrial Catastrophism, Third
Millennium Publishing, Nottingham. ISBN: 0-9525029-2-5
Tags: Woelfli, Baltensperger, Nufer, Planet-Z, Velikovsky, ice ages, Ice Age, Milankovitch Effect,
pole-shift, ice age climate
Citation: Dunbavin, Paul (2020) Throwing Planets Around, in Prehistory Papers, pp 31-45 Third Millennium
Publishing, Beverley, ISBN: 978-0-9525029-4-4
https://www.academia.edu/94905856/Throwing_Planets_Around
Copyright: Paul Dunbavin
February 2020 v1.2
www.third-millennium.co.uk
Throwing Planets Around!
Paul Dunbavin (2020)
Summary
Between 1999 and revised up to 2018 a series of papers proposing the Planet-Z Hypothesis
were published by a group of physicists and astronomers, including the eminent astronomer
Willy Woelfli; these would seek to revise and augment the ideas of Immanuel Velikovsky with
more realistic physics. This article seeks to constructively compare and contrast the strands
of enquiry to date.
The Planet Z hypothesis is granted a greater degree of scientific credibility and exposure than it might
otherwise attain, due to the eminence of the authors and its presence on the Cornell University online
archive. Physics professors can perhaps cite Velikovsky without risking credibility – but no-one else
could expect to have similar work published on such prestigious platforms.
The co-authors of the series of papers are Professor emeritus Dr Willy Woelfli and Professor Dr
Walter Baltensperger; together with Robert Nufer, who describes himself as an amateur astronomer
with a particular interest in comets. Here, to avoid repetition, I shall refer to them as ‘the authors’, or
‘the co-authors’ and cite the papers either collectively or by individual publication date. The
background of the three authors is described in their own papers listed below (Robert Nufer’s
astronomy website is recommended reading). [1]
To attempt a summary of the theories, with apologies for brevity, would be as follows. The 1999
paper (later revised for v1 in 2018) introduces the concept of a periodic close approach by an
additional planet as a possible explanation for Earth’s climatic changes in the past few million years.
This idea was further expanded in the 2002 paper by the same authors. The model simulates a planet
in an eccentric Earth-crossing orbit as a principal cause of the Pleistocene ice ages between 3.5m
years ago and its (apparent) end 11.5k years ago; this planet they term ‘Z’ to substitute for
Velikovsky’s rogue ‘Venus’. The highly eccentric orbit of this hypothetical body allowed several
close approaches during the Pleistocene Ice Age; during these encounters, especially during its final
pass, the tidal forces deformed the Earth resulting in a pole shift that dragged the North Pole away
from Greenland to its present location. The final close-encounter resulted in the break-up of Z which
no longer exists. The age of ice is therefore considered to be over and we are back to the stable
conditions that existed back in the Miocene epoch.
The hypothesis stresses that the Earth’s obliquity was scarcely affected by the Pleistocene encounters
and that the geographical pole shift was caused by a tidal bulge resultant from the close approach of
Z, which altered the rotational balance. They then proceed to calculate the mass, structure and orbital
properties of the transitory planet in order to cause the required tidal effects. In gradualist geological
theories the trigger for ice ages is the drift of a continent over one or both of the poles; in a
catastrophic event such a transition could take place more rapidly due to a pole-shift.
The co-authors comment on the doubtful physics underlying Velikovsky’s original astronomy. Much
stress is also placed upon his letters to Albert Einstein and the physicist’s reply: “Catastrophes yes,
Venus – no!” What a marketing coup that was for an author! But why did the co-authors find it
necessary to commence from a base of 1950’s science? [2]
The computer simulation reveals that the required tidal effects demand an extremely close approach
by a planet with at least the mass of Mars (therefore truly a planet and not a comet). The repeated
visits of the disintegrating Z to the inner solar system would have left a debris trail along its orbit,
thereby triggering a cooling effect, due to the dust veil in space and in our atmosphere. Another
feature of the model is that the close-approaches of Z and its dust veil are considered more influential
upon ice age climate than the Milankovich effect. Since all trace of Z has now gone (save perhaps for
periodic meteor showers) then it must have been either ejected or dissolved, or the fragments fallen
into the sun. Such a break-up demands that in its final approach Z must have entered within the
Earth’s Roche limit – very close indeed!
The authors then offer a discussion of which facts become plausible or explainable by their model.
The most obvious of these is the survival of mammoths in Siberia and the evidence that Siberia was
never covered by an ice cap; Lake Baikal did not freeze and its unique fauna survives; the Himalayas
were not ice-domed as were the Alps. These anomalies are not explainable by gradualist geological
theories. The semi-tropical conditions at mid-latitudes during the ‘interglacials’ are also glossed-over
in gradualist theories, as are the so-called ‘Heinrich events’ when the polar sea-ice apparently brokeup. The co-authors believe that their modelling can also explain such anomalies; it is only the
conclusion of these climate fluctuations that has allowed human civilization to flourish.
The 2007 paper builds upon the earlier studies with more concise information and mathematics. A
further summary of this additional detail would be as follows:
The eccentric orbit of Planet Z caused it to become extremely hot due to ‘tidal work and solar
radiation’. The final close encounter produced a ‘stretching deformation’ of the Earth that was the
ultimate trigger for pole-shift. The hypothesis suggests that the survival of dwarf mammoths on
Wrangel Island indicates a change of latitude and adds further comment that the Milankovitch effect
‘cannot be understood’ without assuming a formerly lower-latitude for Siberia; also that it cannot
explain why the same secular orbital factors did not apply back in the Miocene.
Planet Z must have been breaking-up before the final encounter, but the computer simulation, they
admit, does not allow for this shedding of mass. However they conclude: ‘…that Z had at least 1/10 of
the mass of Earth…’ and remark: ‘For example Z might have been a moon of Jupiter which got loose’
and ‘Clearly, Z had to be hot and emitting material already before the polar shift’. The authors then
consider the lifetime of a cloud of particles from the disintegrating Z:
‘The orbits of the individual particles will be spread over rather vast space so that initially particles
do not collide. Their lifetime is limited by Poynting-Robertson drag … valid for circular motion’ [see
note 3 below].
They argue for traces of the dust cloud in ice-cores and that:
‘A first version of this paper was written under the impression, that a terrestrial origin of the
inclusions in bore ice had been demonstrated’.
However this constraint only applies to the dust rather than any larger fragments residual from the
final break-up. The final pass of the disintegrating Mars-sized Z was described in the 2002 paper:
‘We expect that the peak tidal force has to be about an order of magnitude larger [than previous
encounters]… this brings the closest distance between the centres of Earth and Z into the range of
12,000 to 15,000 km. As a result, Z enters the Roche limit of Earth’.
Regarding the end of the Pleistocene they add:
‘We just note here that the last rapid increase of the temperature recorded in the polar ice data
occurred at 11 500 ± 65 yr BP…Thus, it appears that the Younger Dryas, which begins at 12 700 ±
100 yr BP is younger than the polar shift event’.
A further paper in 2010 was devoted to the folk-memory of these events in various ancient sources.
These references were added because the earlier papers gave rise to comment that Z should be
remembered in the old traditions. Here they cite Chinese myths of ‘persistent daylight’ such that
people were unable to sleep; and the myth of twin suns in the sky. This glow is attributed to the ‘hot’
Z, which they equate with the Typhon comet as recalled by Pliny and other classical writers. A
comparable legend from the Ojibwa of North America is similarly advanced.
Next they cite Herodotus who describes a memory of the sun rising in the west and setting in the east,
as given to him by the Egyptian Priests of Hephaestus; together with their calculation based on a
priest-list that the age of Egyptian civilization stretched back as much as 11,340 years. The authors
cite Herodotus, as did Velikovsky before them, that during this period the sun reversed its positions of
rising and setting twice without detriment to life in Egypt. The late Peter Warlow in The Reversing
Earth would try to explain this by the Earth turning completely upside down on its axis due to a
similar tidal influence. [3] The authors prefer to explain it as a memory of Z in the sky rather than of
the sun.
The authors remark on the Biblical references in Joshua to the sun standing still in the sky; and the
close pass of a fragment of the lost Z as described in the Book of Ezekiel (594 BC – hence long after
the final break-up). Another Biblical citation comes from the Book of Revelation; and a related
quotation from Josephus regarding a time of ancient cataclysm. Reference is also made to the events
of Exodus as a memory of relevant events, but the seven-year famine of Joseph is not cited.
Next they discuss the Egyptian Papyrus Ipuwer (First Intermediate Period) as a memory of the
terminal-Pleistocene pole shift. They would view the papyrus as a recollection of various catastrophes
from much earlier times rather than a reference to contemporary events.
Plato’s Critias and Timaeus are extensively quoted. Here the authors cite the date given by Plato
(Solon) again based on a chronology supplied by Egyptian priests. Therefore, they follow the literal
dating assumption that he describes events at the end of the Pleistocene c.12 000 years BP; and
therefore that an organized state must have existed both in Egypt and Greece at that date
Further memories of the Flood, the authors continue, are to be found in the Epic of Gilgamesh;
preferred here to a discussion of the Biblical Noah. This event they attribute to the tidal forces
produced by the passing planet. The passage of Z is more directly recalled in the words of Ovid’s
Metamorphoses. This recalls the comet Phaethon, perhaps a fragment of Z, which caused burning air
and deserts in the Egyptian Delta and elsewhere. The authors offer a table showing the changes of
latitude required to explain these various recollections, based on the pole shift that they propose.
Of crucial importance is the apparent memory of a change to the number of days in the year from 360
days to our present experience. Here the authors draw again on Velikovsky and state:
“Conservation of angular momentum grants that the direction of the Earth’s axis in space cannot
change appreciably during a catastrophic event”.
The same constraint therefore applies to the diurnal rotation and they take Velikovsky to task on his
physics; he cited Indian, Babylonian, Mayan, Chinese and Egyptian memories of a former 360-day
year. The authors prefer to say:
“What would be modified is Earth’s orbital semi-axis and period rather than the rotation frequency of
the globe.”
In other words they suggest a change to the Earth’s orbit rather than to the length of day.
Overall, computer simulations apart, the series of papers are not unlike many other studies that have
been put out by adherents of Velikovsky and which usually receive the accolade of pseudo-science. It
is only the mathematical modelling and the academic credentials of the authors that allow them to
escape that categorisation. One has to doubt whether anyone lacking such status could achieve
publication of Velikovsky-related theories on such prestigious academic platforms.
The above summary should serve as only an introduction, with apologies again for any omissions or
abbreviation due to brevity; interested researchers should read the original papers in detail and form
their own opinions.
Areas of General Agreement with the Z-hypothesis
As one would expect of a group of physicists, their physics is impeccable. Many enthusiasts and
commentators on the subject of catastrophism, Atlantis, etc, may make loose references to pole-shifts
and axis tilts without understanding that these are not the same thing; or that a vast external force
must be applied to the Earth to bring about the latter. The co-authors do not make these errors.
However, it is not clear whether the orbital mechanics used in their computer simulation have been
peer reviewed.
The 2002 paper shows an illustration of the pole shift as the North Pole spirals away from its former
position over Greenland to its present location. This shift, they propose, was the terminal-Pleistocene
event. The suggested spiralling motion follows the mechanism of the Chandler wobble, but is not
quite complete, as will be discussed below. Overall the computer model predicts a shift of the North
Pole away from Greenland by perhaps as much as 17-18⁰ – but leaving open a lesser magnitude. Note
that this would still allow the South Pole to lie within East Antarctica.
The proposed close approach and tidal bulge, rather than an impact scenario, would explain the lack
of any physical evidence of an impact at the end of the ice-age (There is no known ‘crater’). It offers a
mechanism that could change the geoid of the planet affecting rotational balance – thus triggering a
pole shift – in the absence of hard evidence. However there remain other factors that it could not
explain; both cited within the papers themselves and elsewhere.
The authors are clear in their rejection of a general rearrangement of the planetary orbits and conclude
that Earth’s orbit could be only marginally affected, as would the obliquity in space. The focus
therefore falls upon tidal forces that could cause a geographical pole shift and the effect on the
Pleistocene climate due to the periodic returns of Z and its dust veil.
Divergence from the Z-hypothesis
I shall try here to be constructive in analysis of the hypothesis and to avoid purely negative criticism.
Where the authors depart from their excellence in physics and astronomy then they stand on less firm
ground. Their knowledge of climate and sea-level research is less well demonstrated in the papers.
Another example would be their approach to Egyptology. One doubts whether any Egyptologist
would consider a civilisation with written historical records, in Egypt, or Greece, as far back as
12,500 years ago. At that era the Nile valley was a swamp and the hunter-gatherers who would
become Egyptians were able to live all over the still-green Sahara.
The Z hypothesis takes the literal dates supplied by Plato and Herodotus for the antiquity of Egyptian
civilization and notes their close correspondence with the date of the Pleistocene-Holocene transition.
This apparent correspondence of the terminal ice-age event and the pseudo-Egyptian chronology was
a subject explored in the present author’s earlier books. It can be explained by reference to the
Egyptian belief, found in Manetho, that the antiquity of their state extended back 36,525 years with
the dynasties of kings being preceded by a long list of demi-gods and god-kings. The Egyptians
priests also made the same error as nineteenth-century Egyptologists in treating all the reigns as
consecutive, whereas many kings ruled in parallel in different regions. The fact that we find the long
chronology recorded in two independent sources dating from c.600 BC (Solon and Herodotus) shows
us that this error is ancient.
The confusion in the position of sunrise and sunset is also explainable by standard Egyptology. The
Egyptian civil calendar was not adjusted by an epagominal day (equivalent to Julio-Gregorian 29
February) and therefore wandered through the seasons every 1,460 Julian years (the Sothic Cycle).
Thus it sometimes had summer occurring in ‘winter’ months and vice-versa. This would indeed have
cycled twice during the period of Dynastic Egypt from the predynastic up to the date of Herodotus. It
therefore seems likely that there was a misunderstanding somewhere between the priests trying to
explain this via an interpreter to their visitor, and in the understanding by Herodotus of what was
being described to him. The simplest explanation is always the best and a simple mistranslation is far
more likely than an astronomical cataclysm.
The problem of a former 360-day year is another fragile point in the Z-hypothesis. In the 2010 paper
this world-wide calendar device is employed as a memory of the terminal-Pleistocene changes.
However, the Indian and the Mayan eras, when these changes supposedly occurred, are placed at 3102
BC and 3114 BC in the respective mythologies. This would place it in the mid-Holocene rather than
at the Pleistocene-Holocene transition. Moreover, it cannot be employed as a memory of a change to
Earth’s orbit when the conclusion from the authors’ own simulation is that Earth’s orbit was ‘only
marginally perturbed’. Alternatively, a real modification to the length-of-day would require a
significant change of angular momentum, which the authors agree, could not occur via this
mechanism. The presence of a belief in a former 360-day year, in distant and unrelated ancient
civilizations, must therefore remain an enigma that is not explained by this model.
The proposed pole shift itself is attributed to the mechanism of the Chandler wobble; being merely a
much larger manifestation of the tiny pole-shifts that modern geophysicists regularly monitor. It is
generally conceded that the cause of the modern wobble remains unknown and could therefore be a
vestige of an ancient event. Current geophysical theory suggests that the mechanism would not be a
neat spiral from former pole to new pole as shown in the authors’ illustration. Rather, the pole must
jump instantaneously to a new ‘excitation pole’ and the spiral wobble then commences; however as
the proposed Z passes-by and the location of the bulge progresses, then the axis would jump
repeatedly before the spiral completes. Only when the encounter was concluded would the wobble be
allowed to decay to rest. Moreover, the Earth has a second mode of wobble, which should also be
excited and would interfere with the Chandler wobble. A good mathematical explanation of the
required excitation mechanisms is given in Lambeck’s Geophysical Geodesy (pp 552-5). [4]
The co-authors say in the 2002/2018 paper: ‘Note that this model has only few free parameters’. This
is an admission that: although it may be demonstrable by modelling that a stray-planet in just the right
circumstances could cause the tidal effects (as they have defined them) it is all extremely unlikely. It
has to be just right; in just the right orbit and just the right size; and it has to be just the right
temperature to disintegrate and glow like a second sun. The hypothesis offers us a comforting view
that this unwelcome visitor, which caused the ice ages, is now gone for ever and will not trouble us
again. However, as the author’s themselves conclude: “On the other hand, it creates new problems
that deserve a more complete treatment in future studies”.
The notion that we are now safe from a recurrence of the Ice Age is premature. We see during the
Holocene a series of climate transitions and sea-level variations. There is a pattern of evidence across
various disciplines that points to a lesser climate change and sea-level event in the mid-Holocene,
during the late fourth millennium BC. In Europe, we also find transitions from one stable climate
regime to another (the pollen zones) just as was ongoing during the Ice Age. The mid-Holocene:
Atlantic to Sub-Boreal transition (known as Hypsithermal in North America) is the strongest of these
signals. While fluctuations of temperature could be explained by a dust veil, rapid transitions from
one stable regime to another cannot. These require further astronomical interventions similar to the
terminal Pleistocene event. It is not clear how the fragments of Z, returning to our vicinity, could
cause these unless they impacted; the fragments would not possess sufficient mass to pull a tidal bulge
as is proposed for the main event.
A Mars-sized planet, at the distance of the Moon would appear six-times as large in our sky. If it must
pass within 15,000 km of us in order to cause the required tidal effects then it would fill half the sky
[See Note 4]. Furthermore, not only would it raise a solid-tide and an oceanic tidal bulge, but surely, it
must also draw part of the atmosphere away into space? Noah, floating in his ark, would have no air
to breath; and above his head the sky would be filled by a huge red planet. In other regions the ocean
beds would be sucked dry and land at sea-level would be elevated temporarily into the stratosphere.
Strangely no memory of this is described in the various Flood myths and religious texts from around
the world; although we do find the myths of sky-gods, fiery dragons, second suns, etc; all of which
could be explained by less drastic comet sightings. Commonsense would suggest that Planet Z did not
happen, even though it remains a theoretical possibility that can be modelled in a computer.
A conundrum is that Z has to behave sometimes like a planet; sometimes like a comet. The authors
admit that they have not modelled the change in mass as the repeated returns of Z cause it to break
apart. It must retain the required mass to produce the solid tides; therefore, it must have a rocky, or
even an iron core just like the real Mars. However, it also has to break-up and disappear after repeated
encounters with both Earth and Sun. It should therefore have left a rocky asteroid belt, equivalent to
that between Mars and Jupiter, rather than just a comet-like tail of dust and gas. Surely at least a few
of these larger bodies should still be with us today? If Z is to be just a huge icy comet like, for
example a larger version of 95P/Chiron, then it could not possess the required gravity.
Another consideration is the equatorial bulge. The polar radius is 6,356km while the equatorial radius
is 6,378km; a difference of some 22km. For a postulated 18⁰ pole shift then the pole tide generated is
of the order of 6,500m. This is simply enormous – higher than the Alps. Nineteenth Century science
discussed this and shied away. The Z model, so the co-authors argue, was based on a loose 1000 day
period of relaxation within which the plastic-Earth would conform to the new ellipsoid. Geophysicists
cannot yet give us any certainty as to how long a relaxation of figure might actually take in such
hypothetical extreme circumstances. It should be apparent that during this transition the deep ocean
would spill-over continental interiors, not just the coastal zones. It would sweep away fragile lake
eco-systems such as Baikal, the survival of which the authors have already used to justify the former
position of the poles. We should be finding the bones of Pleistocene whales in the desert.
Many of the objections to Z could be removed if it is not required to return repeatedly and if it is not
employed as the principal cause of ice ages. The fundamental basis for ice-ages is the presence of a
frozen continent at one or both of the poles, together with the Milankovitch cycles due to secular
gravitational pull of the planets. These factors would be present regardless of additional interventions
from space. A single close passage by a massive body, originating from the outer solar system or
beyond, is more plausible. Also, the mass need not be just a planet or comet, if we allow the
possibility of mini-black-holes recently proposed by Scholz and Unwin. [5] There may be more than
one type of astronomical cause for past climate episodes and a Z-type body is just another to add to
the list.
Causes of ice ages apart, as to whether the tidal bulge mechanism is the right one to explain the
terminal ice-age event depends upon what it is required to explain. If it is to trigger solely a pole-shift
then it remains a candidate; however if it must also explain a change of obliquity or the length of day,
or a change to the orbit, then we must look for other ways to apply the necessary energy without
leaving hard evidence.
In their closure summary (2007) the co-authors, as is usual, suggest the need for further study. In their
own words: ‘In the case that these contradict the given estimates, they could primarily question this
particular scenario, rather than the evidence that a pole shift has occurred’.
So, we are in agreement that a pole shift occurred; the disagreement is: more than one and more than
one possible cause.
Notes and References
Note 1
This author’s own work on catastrophism, in parallel but slightly preceding the Z hypothesis (published 19952005 and 2017) has always avoided comparisons with Velikovsky. [6] Since reading his books in the 1960s –
long before I began any serious research into ancient catastrophism – I consciously avoided reading or citing
them in order not to become associated with his unique astronomy – but there is no escape from it. The Z
hypothesis was just one more strand of Velikovsky-like research to evade. It would have been better if the
authors of the Z-hypothesis had let it stand alone rather than citing Velikovsky in so many places, as I remain
unconvinced that he actually believed everything that he wrote. In this author’s books (1995-2017) a similar
pole shift mechanism based on the Earth’s wobble was explored primarily in support of a mid-Holocene event,
but also acknowledged the occurrence of a much larger event at the Pleistocene-Holocene boundary. A
discussion of alternative pole-shift mechanisms due to low-mass, high-energy impacts may be found at
https://www.third-millennium.co.uk/dangers-from-ancient-supernovas.
Note 2
All comments here are based on the v1 versions of the subject papers available at arxiv.org. The older versions
on the Los Alamos website (lanl.gov) that are cited within the papers themselves and elsewhere could not be
obtained and have not been cited other than where the authors update their own thinking.
Note 3
An explanation of Poynting-Robertson drag may be found at:
https://academic.oup.com/mnras/article/460/1/802/2608912
Note 4
Earth's diameter is 12,742 km and the moon is 384,400 km distance; (30.168 diameters) The Roche limit for the
Earth-Moon system is approx: 18,470 km (1.45 diameters). The solid earth tide due to the pull of sun and moon
is of the order of 20 cm, and can exceed 30 cm.
Principal Sources Discussed
1999
W. Wölfli, W. Baltensperger (1999) A possible explanation for Earth’s climatic changes in the past few million
years, http://xxx.lanl.gov/abs/physics/9907033 [Link broken – see note 2 above]
W. Wölfli, W. Baltensperger, A possible explanation for Earth’s climatic changes in the past few million years,
Notas de Fisica, Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, CBPF-NF-031/99, (June 1999). More
recent version: http://arxiv.org/abs/astro-ph/9909464v1 [this link and the 2018 link go to the same page,
where a 2018 pdf is shown]
2002
W. Woelfli and W. Baltensperger (2002) An additional planet as a model for the Pleistocene Ice Age, CBPF,
Notas de Fısica 007/02 or http://arxiv.org/abs/physics/0204004; http://arxiv.org/abs/physics/0204004v1
2006
W. Woelfli and W. Baltensperger (2006) Arctic East Siberia had a lower latitude in the Pleistocene,
http://arxiv.org/abs/physics/0604029 or CBPF, Notas de F´ısica, NF-008/06, March 2006.
2007
W. Woelfli and W. Baltensperger (2007) On the change of latitude of Arctic East Siberia at the end of the
Pleistocene, http://arxiv.org/abs/0704.2489
2010
W. Woelfli and W. Baltensperger (2010 September 26) Traditions connected with the pole shift model of the
Pleistocene http://arxiv.org/abs/1009.5078v1
2018
R. Nufer, W. Baltensperger and W. Woelfli (2018 March 29) Long term behaviour of a hypothetical planet in a
highly eccentric orbit http://arxiv.org/abs/astro-ph/9909464; http://arxiv.org/abs/astro-ph/9909464v1
Other References
1. https://robertnufer.ch/
2. Palmer, Trevor (2018) Perilous Planet Earth Revisited, Chronology and Catastrophism Review 2018:2, 3-19
https://www.academia.edu/41250309/Perilous_Planet_Earth_Revisited_Chronology_and_Catastrophism_Revie
w_2018_2_pp._3-19
3. Warlow, Peter (1982) The Reversing Earth ISBN 10: 0460044788 - ISBN 13: 9780460044783 - Weidenfeld
& Nicolson, London.
4. Lambeck, Kurt (1988) Geophysical Geodesy: The Slow Deformations of the Earth. Clarendon Press, Oxford
ISBN: 0-19-854438-3.
5. Scholz, Jakob and Unwin, James (2019). What if Planet 9 is a primordial Black Hole?
https://arxiv.org/pdf/1909.11090.pdf
6. Dunbavin, Paul (2005) Under Ancient Skies, Ancient Astronomy and Terrestrial Catastrophism, Third
Millennium Publishing, Nottingham. ISBN: 0-9525029-2-5
Tags: Woelfli, Baltensperger, Nufer, Planet-Z, Velikovsky, ice ages, Ice Age, Milankovitch Effect,
pole-shift, ice age climate
Citation: Dunbavin, Paul (2020) Throwing Planets Around, in Prehistory Papers, pp 31-45 Third Millennium
Publishing, Beverley, ISBN: 978-0-9525029-4-4
Copyright: Paul Dunbavin
www.third-millennium.co.uk
February 2020 v1.2
Paul Dunbavin