Aurora Borealis

The oldest surviving datable record of a sighting of the polar aurora is currently held to be a Babylonian report for 12-13 March 567 BC. Here it is argued that Chinese observations of a ‘five-coloured light’, a set of nocturnal white rainbows and other ‘luminous emanations’ dating to the mid-10th century BC are earlier impressions of auroral displays. These records have only survived in secondary sources, but their authenticity and auroral import are supported by the scientifically reconstructed parameters of the geomagnetic field for the period in question.

This article is composed of materials taken from my book 'On the Origin of Myths in Catastrophic Experience', vol. 2: 'The Earth's Aurora' (2021), pp. 28-29, 35-38, 48, 55-56.  Because it offers no new content, it would have been unethical to submit it to a peer-reviewed journal for publication.

Auroral records found in historical archives and cosmogenic isotopes found in natural archives have served as sound proxies of coronal mass ejections and solar energetic particles (SEPs), respectively, for dates prior to the onset of telescopic sunspot observations in 1610. These space weather events constitute a significant threat to a modern civilization, because of its increasing dependency on an electronic infrastructure. Recent studies have identified multiple extreme space weather events derived from SEPs in natural archives, such as the event in 660 BCE. While the level of solar activity around 660 BCE is of great interest, this had not been within the coverage of the hitherto-known datable auroral records in historical documents that extend back to the 6th century BCE. Therefore, we have examined Assyrian astrological reports in the 8th and 7th centuries BCE, identified three observational reports of candidate aurorae, and dated these reports to approximately 680 BCE-650 BCE. The Assyrian cuneiform tablets let us extend the history of auroral records and solar activity by a century. These cuneiform reports are considered to be the earliest datable records of candidate aurorae and they support the concept of enhanced solar activity suggested by the cosmogenic isotopes from natural archives.

Transient celestial phenomena feature prominently in the astronomical knowledge and traditions of Aboriginal Australians. In this paper, I collect accounts of the Aurora Australis from the literature regarding Aboriginal culture. Using previous studies of meteors, eclipses, and comets in Aboriginal traditions, I anticipated that the physical properties of aurora, such as their generally red colour as seen from southern Australia, would be associated with fire, death, blood, and evil spirits. The survey reveals this to be the case and also explores historical auroral events in Aboriginal cultures, aurorae in rock art, and briefly compares Aboriginal auroral traditions with other indigenous groups, including the Maori of New Zealand.

Cultural anthropologists often use the term axis mundi in a looser sense than the strict astronomical one. This poses a problem, because the objects they identify as "axis mundi" in mythological and early cosmological sources do not correspond to the present state of the axis of the earth. The association of these objects with the axis of the earth does not appear to have been made explicitly and unambiguously before the 1st millennium BCE, probably because the rotation of the earth around its axis was not commonly known in earlier times. By contrast, the mythological phenomenon loosely identified as the axis mundi dates back to the earliest stages of civilisation and is described by the most diverse cultures in remarkably similar terms. It can be explained by reference to a once visible entity in the sky, with a complex, evolving morphology and a possible link to the zenith or the pole. The prototype may have been the zodiacal light or, as recent insights in plasma physics indicate, an enhanced aurora formed in prehistoric times.

Works is solely authored by  Finnish Academy of Sciences, Professor S. Lemstrom, chief of the Finnish Meteorological Observatory at Sodankyla.

At a point in North Finland, just within the Arctic circle, the professor constructed a network of wire on two conical mountains, which were respectively about 2,600 feet and 3,600 feet high. Hills of this shape were chosen because, as is well-known, electricity gathers most readily about sharp eminences. If mankind possessed an electro-static sense, and could perceive electricity as they can light, then we should see this now mysterious agency everywhere diffused in the world, and from all the edges, corners, and sharp points of rocks and hills, and church spires, and even the tips of the leaves of plants'and trees, we should Observe unceasingly at work day and night electric streamers keeping up the balance of Nature. Nothing in the visible universe is more grand or more varied as scenery than in all probability would be the aspect of the universe which such a sense would afford. It is now known beyond question that every species of motion, every change Of temperature, every mode of friction, however slight, between any two dis-similar substances—though they be mere atoms in size—the daily course of the sun round the earth, the tidal strain which the moon exerts on the sea. and on the solid crust of the globe, as well as every chemical combination, produces or is accompanied by electrical disturbance. The professor knew, therefore, that to and from these hill-tops electricity was darting ; by experiment he determined to hasten the process and to render it visible.

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Creation myths around the world reveal an intricate network of recurrent counterintuitive motifs, describing a time when the sky was low, the stars did not yet shine, multiple suns appeared, a ‘world axis’ in the form of a tree, ladder or giant man connected the earth with the sky, a devastating flood or fire ended the old order, and so forth. The present work, in multiple volumes, seeks an origin for these traditions in a series of extraordinary natural events relating especially to the earth’s transition from the last glacial period to the Holocene.

This first volume sets the stage for the interdisciplinary hypothesis. Essential lines of research receive a historical introduction: comparative mythology, catastrophism and the study of the mythical world axis in relation to the earth’s rotation. Various astronomical and meteorological interpretations that are not strictly catastrophist are explored for several types of myths about the sun, the moon and the world axis, but leave many of the most intriguing traditions unexplained. It is argued that a structural core of the worldwide mythology of ‘creation and destruction’, in which the cosmic axis takes pride of place, points to a specific period of dramatic natural circumstances in real prehistoric time. A new synopsis is provided of this universal mythological substrate. It emerges that the mythical world axis cannot have been based on a single object seen or imagined at one of the poles, as has usually been supposed. This surprising conclusion paves the way for the innovative geomagnetic theory proposed in volume 2.

ISBN 978-1-9994383-2-6
With a foreword by Professor Trevor Palmer
XXXV + 441 pages, including 117 illustrations and index

or tens of thousands of years, humans have expressed themselves artistically on their surroundings-painting, etching, carving, and molding designs, decorations, and imagery on surfaces by mar in us anthony van der s lu i j s and anthony l. per at t astronomical petroglyphs w w w. p e n n. m u s e u m / e x p e d i t i o n 33 Marinus Anthony van der Sluijs, Matt Applebaum (illustration) Above, is this a "snake," a meandering river, or an image from the artist's imagination? (from Rinconada Canyon, Petroglyph National Monument, New Mexico, USA). 42 volume 52, number 2 expedition Jarosław zrałka (left) and wiesław Koszkul Marinus Anthony van der Sluijs with a petroglyph showing an anthropomorphic creature with two "antennae" (from Chichictara, Palpa Province, Peru).

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In this second volume, the earth’s magnetic field and aurora take centre stage. Geomagnetic reversals are rare occasions when the field dwindles, the north and south magnetic poles trade places, and minor poles come into play. This process remains incomplete in the much more frequent case of a geomagnetic excursion. Throughout human history, people have personified and mythologised the aurora. If a geomagnetic excursion had occurred within human memory, they could have observed spectacular transformations of the lights, even at low latitudes, and enshrined these in myths, monuments, images and rituals. Many elements of the primordial condition described worldwide may thus be explained – awe-inspiring luminous rings, arcs and columns, often dynamic and structured, that seemingly held up a gloomy, low-hanging sky.

Evidence is cited for two excursions that could have informed age-old traditions in this way. Specialists dispute both and a way out of the controversy is proposed. The unique effects that a geomagnetic reversal or excursion must have on the aurora are further explored through possible contemporary parallels on other solar-system bodies and in experimental work on terrellae, of which a historical survey is given. A wealth of new information is provided throughout on the history of geomagnetic studies and auroral physics.

ISBN 978-1-9994383-3-3
With a foreword by Dr. C. J. Ransom
XXXIII + 516 pages, including 168 illustrations and index

Many tourists who visit Iceland desire a unique and genuine Icelandic experience. One of the things that attracts international visitors to the country is its northerly position, its alien brightness and the interplay of landscape and climate. An important part of this is the northern lights. With the increased interest shown by foreign visitors, many Icelanders now desire to inform their guests and to share information about the culture of the past. How common were the northern lights over Iceland in days gone by? Did early Icelanders descry something in the northern lights more readily in other conditions than now, when the stimuli were fewer and the darkness deeper? Did they leave behind stories about the northern lights and do such stories leave traces of superstition related to them? And finally, does something indicate that the northern lights are more common in the oldest sources than people have supposed up until now? In this article the sources on the northern lights, as well as stories about them, will be called forth and placed in context. These are all Icelandic tales that have been preserved from the past until today, and behind them superstition may certainly be discerned, which shows that Icelanders since olden times have been fascinated by the northern lights, and detected something in them in the fullest sense of the word, which they believed to have predictive qualities.

The purpose of the present paper is to analyse the mental and cultural attitudes of early medieval people towards one celestial “unidentified” phenomenon: aurora borealis. Celestial signs were often – but not always - interpreted on the basis of biblical prophecies, as visible words through which God forewarned humanity of future major events like the death of a king, pestilence, or famine. Attention will be mainly focused on the latter aspect, and specifically on the potential connection between the signs associated with the end of times in the Gospels, and actual records of aurorae, which were in turn interpreted as proving and confirming biblical prophecies. Aurora borealis seems to have generated anxiety about climate and hunger and to have enjoyed a particularly bad reputation, the reasons depending either on the moral purposes of related records, the rhetorical strategies they offered, or the actual emotional impact they had on the observers.

A widespread motif in archaic cosmologies that has received little attention among scholars is the idea that the sky is formed of a solid substance and that it contains one or more openings, that enable "traffic" between the regions above and below. This article presents a cross-cultural documentation of this motif and argues that the notion of "sky holes" derived from observations of aurorae or "polar lights," specifically from auroral arcs and coronae. The phenomenology of these types of aurorae also sheds light on a number of related beliefs - that the hole is situated on the horizon or near the celestial pole; that it frequently shuts and opens again; and that the sun or another light shines through it.

The Astronomical Diaries from Babylonia (ADB) are an excellent source of information of natural phenomena, including astronomical ones, in pre-Christ era because it contains the record of highly continuous and systematic observations. In this article we present results of a survey of aurora-like phenomena in ADB, spanning from BCE 652 to BCE 61. We have found 9 records of aurora-like phenomena. Philological and scientific examinations suggest 5 of them can be considered as likely candidate for aurora observations. They provide unique information about the solar and aurora activities in the first millennium BCE.

Acceleration of the Solar Wind: a new model for the generation of the necessary suprathermal electrons in the solar Transition Region by Robert J. Johnson ………….. A Geomagnetic Approach to Traditions of Axes Mundi, Part II by Marinus Anthony van der Sluijs ………………………………………………………………………………..

Spectral analyses of the Chinese auroral records dating from 300 AD using maximum entropy, Fourier and autocorrelation methods have revealed significant periods. The power spectral density of the auroral records has a strong multiplet of spectral lines centered on the median period. The prominent period is 200 years followed by enveloping bands of 80-130, 40-60 and 20-30 years. Nonstationarity is found for periods less than 120 years. The similarity of these periods with intervals between sunspot minima and other solar-terrestrial parameters is noted.

The astronomical diaries from Babylonia (ADB) are excellent sources of information of natural phenomena, including astronomical ones, in pre-Christ era because it contains the record of highly continuous and systematic observations. In this article, we present results of a survey of aurora-like phenomena in ADB, spanning from BCE 652 to BCE 61. We have found nine records of aurora-like phenomena. Philological and scientific examinations suggest that five of them can be considered as likely candidate for aurora observations. They provide unique information about the solar and aurora activities in the first millennium BCE.

This article traces the spread and development of the motif of the ourobóros, or circular serpent, and proposes that it originated in descrip-
tions of an intense aurora. The earliest artistic examples of the ourobóros date to ±5000–±3000 BCE. The theme proliferated in Egypt and spread to the classical world during the Hellenistic period. In the earliest traditions, emphasis was on the ourobóros’ associations with the sun god, the creation of the world, the circular ocean, darkness or underworld thought to surround the earth, and a mythical combat. From late antiquity onwards, the ourobóros acquired more sophisticated meanings, including a link with the ecliptic band or the zodiac, the lunar nodes, the alchemical process, and eternity. In China, the ourobóros largely remained a purely decorative motif, while its most common role in the equatorial regions of America, Africa and Oceania was as a form of the cosmic ocean.  In reviewing hypotheses concerning the origin of the motif, we consider the antiquity of the theme, its near-universality, its geographic link with the outermost boundary of the visible world, and aspects of the dragon’s prosopography—such as its precious orb, its filamentation, its twin aspect, and its radiant color scheme. It is proposed that the archetype was inspired by a surge of intense auroral phenomena including a plasma instability type known as a diocotron instability, witnessed by human beings towards the end of the Neolithic period.

The fourth volume in the series Aurorae Borealis Studia Classica consists of the Jesuit Maximilianus (Maximilian) Hell's monograph on the Aurora Borealis, first written as a paper for the Royal Society of Sciences in Copenhagen (MS, c. 1770), then published in a slightly enhanced Latin edition (1776) and finally in a German edition by L.A. Jungnitz (1792). These are introduced by a biographical essay and summaries of contents by Per Pippin Aspaas. Facsimiles of the original works are freely available at http://septentrio.uit.no/index.php/aurora/index

Knowledge of solar variability and its effects on the Earth is essential since the Sun affects almost every aspect of our lives. Direct observations of the Sun, usually of sunspots, with some continuity, exist only since about 1700. Understanding of long-term solar variability must then depend on proxy data, such as visual auroral observations, measurements of magnetic activity, and the radiocarbon record. These also give us information on the interaction between the solar wind, the interplanetary field, and the terrestrial magnetosphere, as well as, for the radiocarbon record, hellospheric conditions. This paper uses a data base of visual auroral observations for a period of about 500 years, from 1450 to 1948, comprising about 45,000 observations, in addition to the well-known sunspot series and the magnetic activity index aa, from 1868 to 1990. The secular variation of the aurora is examined and compared, where possible, to sunspot data and magnetic activity data. Blackman-Tukey power spectra are used to determine periodicities. The study confirms the variability of the periodicities in both frequency and amplitude. In particular, the well-known 11.l-year cycle disappears during the Maunder minimum and at the end of the eighteenth and beginning of the nineteenth century. While the 11.l-year period is normally strongly dominant for sunspots, other shorter periods become important, and even dominant, for auroras and magnetic activity. Consequently, the temporal behavior of these three variables differs. Prolonged solar activity minima are clearly evident. In addition to the known Sptrer, Maunder, Dalton, and 1901-1913 minima, a previously unrecognized minimum about 1765 is clearly evident in the data. Comparison of the depth of these minima shows that the Dalton minimum may be the deepest, or at least rivals the Maunder minimum in importance. This minimum clearly deserves further study. Combining the polar data base with that of mid-latitudes provides for the first time a globally comprehensive historical record of auroral occurrence. The data provide confirmation of the anticorrelation of auroral occurrence in the polar regions with sunspot activity, as a result of displacement of the auroral oval with changes in solar and magnetic activity. Assuming the validity of some current models of the solar origin of geomagnetic activity, the data provide a basis for understanding the variation over time of the general magnetic field of the Sun, in particular the polar field. 1. INTRODUCTION Life on the Earth depends on the Sun. This simple statement disguises a considerably complex situation. The Sun itself shows a degree of variability. This is evident in observational measures such as visual and telescopic observations of sunspots and other surface features, as well as in such parameters as the magnetic fields of sunspots or the general magnetic field. Further, the Sun emits both radiation and particles. Travel of the particles is influenced by the interplanetary magnetic field, and, in the vicinity of the Earth, by the terrestrial magnetosphere. If we wish to understand solar behavior and the interactions between Sun, interplanetary field, and terrestrial magnetosphere, we must look to measures of solar activity directly derivable from solar observations, such as sunspots, and to terrestrial observations (the end results of the travels of particles and radiation to the Earth). Solar variations, to be properly understood, must consider temporal intervals of centuries or even millennia. Many, perhaps even most, scientists have a vague idea that the Sun varies with a period of 11 years and that this behavior has continued since the Earth's beginning. In fact, the Sun's variability is described by many periods whose amplitudes change over time. There are, furthermore, as pointed out most recently by Eddy [ 1976], intervals of prolonged minima in solar activity. Thus a proper understanding of the Sun must begin with the determination of solar periodicities, theft changes over time, and any unusual features in these parameters. The results provide data which any physical model of the Sun must explain. In determining solar periodicities and theft behavior we are hampered by the relatively short period within which detailed, "proper," scientific observations have been carried out. We must depend for longer intervals on less well defined, less resolved, more sporadic observations of only a few parameters, including proxies for solar activity. Primarily, these are observations of sunspots, visual auroral observations, magnetic activity, and radioisotope measurements, especially those of •4C.

Geomagnetic virtual pole positions (VGP's) calculated from archaeomagnetic directional data are compared with three ancient accounts of low latitude observations of the Aurorae boreales, viz. by Aristotle (384-322 BC), Seneca (55 BC-40 AD) and simultaneously by Chinese astronomers in Hangzhou, China and by European observers in Prague in 1138 AD, October 13th. The geomagnetic latitudes of these VGP's ranged from 65 " to 70 ". Inclination and declination values have also been calculated for the regions of interest, assuming dipole field symmetry. The reduced archaeomagnetic results used, comply with those early observations of aurorae, confirming the inclination of the geomagnetic pole towards the observing sites. A critical evaluation of the aurora1 types is given, associated to the low latitude aurora. The latter, is furthermore, discussed in relation to the ancient descriptions of the aurora phenomenon. A critical discussion is also made on severe magnetic storms-related aurora. It has been shown that the appropriate use of relevant VGP's, in our study, is not influenced by discernible non-dipole disturbances.

Tutti i diritti riservati. È vietata la riproduzione di testi e illustrazioni senza il permesso scritto dell'Editore. Hesperìa: studi sulla grecità di Occidente. -1. -Roma: «L'ERMA» di BRETSCHNEIDER, 1990-. -v. ; 24 cm Irregolare Alcuni numeri della rivista hanno carattere monografico e sono dotati di un titolo proprio ISBN 978-88-913-0290-8 (brossura) ISBN 978-88-913-0294-6 (pdf) CDD 21.930.1 1. Archeologia classica Il volume è stato pubblicato con il patrocinio di

The Astronomical Diaries from Babylonia (ADB) are an excellent source of information of natural phenomena, including astronomical ones, in pre-Christ era because it contains the record of highly continuous and systematic observations. In this article we present results of a survey of aurora-like phenomena in ADB, spanning from BCE 652 to BCE 61. We have found 9 records of aurora-like phenomena. Philological and scientific examinations suggest 5 of them can be considered as likely candidate for aurora observations. They provide unique information about the solar and aurora activities in the first millennium BCE.

Auroral reports from ancient Chinese records and from Greece and Italy, from historical sources (Bamboo Annals, Tai ping yu lan, Ch'unch'iu period and Aristotle, Anaxagoras, Seneca, Pliny, Livy, respectively) in the 1st millennium B.C., are discussed in relation to the geomagnetic pole (GP) coordinates through archaeomagnetic inclination and declination data. It is shown that the expected auroral oval with its extension to a maximum of radius 30o around the GP occasionally reaches the Chinese / Southern Mediterranean mid latitudes and eastern longitudes: for China 35ο-40ο and 95ο-125ο respectively, and for Greece/Central Italy, 35ο-40ο and 10ο-25ο respectively; two distant regions where two great cultures flourished. Of the nine Chinese records those of 1000-900 B.C., 687 B.C., 193 B.C., 139 B.C., 32 B.C., 30 B.C. and 15 B.C. records are justified by a mid latitude geomagnetic pole which gives certain mid latitude aurorae. For the 166 B.C. and 154 B.C. available archaeomagnetic data the position of the VGP does not justify observation of aurorae. Archaeomagnetic data for Chinese accounts derived from South Korea, Japan and England reduced to mid China location are also used to determine GP at a reduced site of common latitude in China, but due attention and discussion of non-dipole magnetic sources and their calculated drift rates is made, to explain the unattainable observation of aurorae at central Chinese latitudes. Similarly, in southern Eastern Mediterranean area (Greece, Italy) 33 data are used and most are commensurable with the inclined GP towards mid latitudes, included within the auroral oval or at its southern maximum extension taking into account associated errors. Highly acceptable aurorae accounts and problematic ones are explained in terms of smooth or rapid, respectively, changes in the magnetic inclination and declination positions, reinforced by large age errors. Virtual Geomagnetic poles (VGP) for examined regions are ranging between 51o to 71o for latitude and between 1o to 123o for longitude for auroral observation dates of the 1st millennium B.C. to 1st century A.D.

The Astronomical Diaries from Babylonia (ADB) are an excellent source of information of natural phenomena, including astronomical ones, in pre-Christ era because it contains the record of highly continuous and systematic observations. In this article we present results of a survey of aurora-like phenomena in ADB, spanning from BCE 652 to BCE 61. We have found 9 records of aurora-like phenomena. Philological and scientific examinations suggest 5 of them can be considered as likely candidate for aurora observations. They provide unique information about the solar and aurora activities in the first millennium BCE.

This research presents a centralized boundary object website and mobile app focused on allowing participants to participate in developing an early warning system through space weather and the beauty of the aurora borealis. Because of the beauty and majesty of auroral activity, people will seek information about when and where these unpredictable events occur. This activity, commonly referred to as nowcasting, can be combined with scientific data collected from observatories and satellites and serve as an early warning system with potentially far greater accuracy and timeliness than the current state of the art. We believe that long-term engagement with a citizen science tool will help bridge the many social worlds surrounding the aurora borealis and lead to the development of an early warning system that may correlate the visibility of the northern lights to violent space weather. We hope this will lead to other real time crowdsourced early warning systems in the future.

Auroral reports from ancient Chinese records and from Greece and Italy, from historical sources (Bamboo Annals, Tai ping yu lan, Ch'unch'iu period and Aristotle, Anaxagoras, Seneca, Pliny, Livy, respectively) in the 1 st millennium B.C., are discussed in relation to the geomagnetic pole (GP) coordinates through archaeo-magnetic inclination and declination data. It is shown that the expected auroral oval with its extension to a maximum of radius 30 o around the GP occasionally reaches the Chinese / Southern Mediterranean mid latitudes and eastern longitudes: for China 35 ο-40 ο and 95 ο-125 ο respectively, and for Greece/Central Italy, 35 ο-40 ο and 10 ο-25 ο respectively; two distant regions where two great cultures flourished. Of the nine Chinese records those of 1000-900 B.C., 687 B.C., 193 B.C., 139 B.C., 32 B.C., 30 B.C. and 15 B.C. records are justified by a mid latitude geomagnetic pole which gives certain mid latitude aurorae. For the 166 B.C. and 154 B.C. available archaeomagnetic data the position of the VGP does not justify observation of aurorae. Archaeo-magnetic data for Chinese accounts derived from South Korea, Japan and England reduced to mid China location are also used to determine GP at a reduced site of common latitude in China, but due attention and discussion of non-dipole magnetic sources and their calculated drift rates is made, to explain the unattainable observation of aurorae at central Chinese latitudes. Similarly, in southern Eastern Mediterranean area (Greece, Italy) 33 data are used and most are commensurable with the inclined GP towards mid latitudes, included within the auroral oval or at its southern maximum extension taking into account associated errors. Highly acceptable aurorae accounts and problematic ones are explained in terms of smooth or rapid, respectively , changes in the magnetic inclination and declination positions, reinforced by large age errors. Virtual Geomagnetic poles (VGP) for examined regions are ranging between 51 o to 71 o for latitude and between 1 o to 123 o for longitude for auroral observation dates of the 1st millennium B.C. to 1 st century A.D.

Knowledge of solar variability and its effects on the Earth is essential since the Sun affects almost every aspect of our lives. Direct observations of the Sun, usually of sunspots , with some continuity, exist only since about 1700. Understanding of long-term solar variability must then depend on proxy data, such as visual auroral observations, measurements of magnetic activity, and the radiocarbon record. These also give us information on the interaction between the solar wind, the interplanetary field, and the terrestrial magnetosphere, as well as, for the radiocarbon record, hellospheric conditions. This paper uses a data base of visual auroral observations for a period of about 500 years, from 1450 to 1948, comprising about 45,000 observations, in addition to the well-known sunspot series and the magnetic activity index aa, from 1868 to 1990. The secular variation of the aurora is examined and compared, where possible, to sunspot data and magnetic activity data. Blackman-Tukey power spectra are used to determine periodicities. The study confirms the variability of the periodicities in both frequency and amplitude. In particular, the well-known 11.l-year cycle disappears during the Maunder minimum and at the end of the eighteenth and beginning of the nineteenth century. While the 11.l-year period is normally strongly dominant for sunspots , other shorter periods become important, and even dominant , for auroras and magnetic activity. Consequently, the temporal behavior of these three variables differs. Prolonged solar activity minima are clearly evident. In addition to the known Sptrer, Maunder, Dalton, and 1901-1913 minima, a previously unrecognized minimum about 1765 is clearly evident in the data. Comparison of the depth of these minima shows that the Dalton minimum may be the deepest, or at least rivals the Maunder minimum in importance. This minimum clearly deserves further study. Combining the polar data base with that of mid-latitudes provides for the first time a globally comprehensive historical record of auroral occurrence. The data provide confirmation of the anticorrelation of auroral occurrence in the polar regions with sunspot activity , as a result of displacement of the auroral oval with changes in solar and magnetic activity. Assuming the validity of some current models of the solar origin of geomagnetic activity, the data provide a basis for understanding the variation over time of the general magnetic field of the Sun, in particular the polar field.

Geomagnetic virtual pole positions (VGP's) calculated from archaeomagnetic directional data are compared with three ancient accounts of low latitude observations of the Aurorae boreales, viz. by Aristotle (384-322 BC), Seneca (55 BC-40 AD) and simultaneously by Chinese astronomers in Hangzhou, China and by European observers in Prague in 1138 AD, October 13th.