The History of Man in a Circle among the Stars
Have you ever seen those splendid long-posed photographs that capture the rotation of the
stars near the north celestial pole?
Practically at the centre of that whirlwind drawn by the movement of the celestial vault
is the most famous of all the stars, the North Star, or Polaris, as it is also called in
Latin starting from the 18th century.
From the celestial North Pole it is only 0.7°, almost one and a half times the disk of the
full Moon.
This may seem like a lot, but compared to the angular extension of the whole sky it
is really little... so much so that the Polaris, unlike the ever wider arches left by the stars
progressively further away from the Pole, even in long pose photos it appears practically
punctiform.
The stars very close to the imaginary point of rotation give the impression of not participating
in the apparent rotation of the sky.
And it is because of this peculiarity that Polaris has become the symbol of the cardinal
point par excellence, that of the North direction; which in our hemisphere has represented one
of the first forms of adaptation of man to his natural environment: orientation.
But has it always been like this?
Are we really sure?
The men of our time have lived or live in a world where since they were born there has
existed only one "polar star", the one that identifies the end of the tail of the Lesser
Bear and which in Latin is called Alpha Ursae Minoris.
But it has not always been so.
The Earth's axis of rotation, in fact, while maintaining the same inclination to the ecliptic,
does not always point in the same direction, but like a spinning top that cannot keep vertical,
and begins to oscillate slowly describing with its axis an inverted cone, so the Earth's
axis during a cycle almost 26,000 years long draws in the sky a circle of radius equal
to the angle of inclination, or 23.5°.
This circle crosses the circumpolar constellation, bringing ever-changing stars closer in time.
It is therefore only by pure chance that in this historical period it is the Alpha Ursa
Minoris star that is prospectively very close to the celestial Pole.
In fact, it was only from the end of the 12th century that Alpha Ursae Minoris began to
be referred to as the "polar star"... polar star.
This astronomical curiosity, which in astronomy is called "Precession of the equinoxes", can
allow us to establish a parallel between what was happening in the sky and what was happening
on Earth in the last 26,000 years, and to relate the alternation of the different "polar
stars" with human events.
Our journey through time begins many millennia ago, when the men who populated a still uncontaminated
Earth were lost in its wide spaces in search of what they needed to live (fruits to harvest,
animals to hunt for meat and skins, places with a more favorable climate to better withstand
the rigors of the Ice Age).
Not much is known about those men; what is known about them is the result of a difficult
work of reconstruction by paleontologists based on very few elements (very ancient finds
found in caves or after excavations).
25,800 years ago: Alpha Ursae Minoris In a land still shrouded by the great glaciations,
in which the forests advanced from the centre of Europe towards the North, interrupted by
the ice covering the northern part, rare nomadic populations live in conditions made very difficult
by the hostile climate, procuring food through hunting and harvesting berries and fruits.
In the communities of the increasingly rare Neanderthals, and also in those of the emerging
cro-magnons, the average life span of an adult barely reaches 30 years of age, yet these
hostility-hardened people find ways of mixing natural pigments to obtain dyes, and of portraying
human and animal figures with them; not only that, but they also carve and sculpt ivory
figurines, or model figures out of clay, which they then dry to produce female images that
recall a promise of fertility; the difficult struggle for survival does not prevent the
appearance of a rudimentary sensitivity to beauty.
The first essential "musical instruments", and also some strange engravings on pieces
of bone that seem to represent the sequence of the phases of the moon, are from this period.
Who knows if those men, looking at the cold cloudless night sky, ever noticed a bright
star that remained fixed at the centre of all the others; who knows if even in the migrations
of that time it was the guide for men as it has been in the most recent history for our
navigators.
That star was Alpha Ursae Minoris, the brightest of the Ursa Minoris constellation, which around
23,500 B.C., just as it is today, shone less than one degree away from the celestial pole.
And it was perhaps our "polar star" that indicated the path to those peoples who, from the heart
of Asia, chasing the great herds of herbivores on which their lives depended, crossed the
frozen isthmus that was where the Bering Strait now lies, and penetrated that enormous uninhabited
continent that we now call America.
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20,000 years ago: Alderamin (Alpha Cephei) This was the period that accompanied the definitive
decline of the Neanderthals, who in the space of a few thousand years became completely
extinct, replaced throughout Europe by the more evolved Cro-magnon: the first representatives
of the "homo sapiens sapiens" species, the same species to which we belong.
The rise of these last arrivals, favoured by the end of the great glaciations and the
consequent improvement of the climate, leads to a better organisation of resources: from
small groups composed of a few families to larger tribes, with a rigorous distribution
of tasks in the double furrow of hunting and gathering.
The strengthened social relations lead to the emergence of burial rites aimed at comforting
those who remain with the certainty of a life that will continue after death.
The need to express fears and hopes through signs, colours and self-representations is
overwhelmingly born.
Entire caverns are frescoed, like those of Lascaux and Altamira, and with the mystical
experience of the transcendent, artistic creation is also born as a moment of reflection on
one's existence.
And in the sky under which the first "thinkers" raise their heads to question themselves about
the world, there is now another star indicating the direction of the North, the one we know
by the name of Alderamin, the white alpha Cephei (magnitude.
+2.4), about 3° away from the pole.
From 12,000 to 15,000 years ago: Vega, Delta Cigni and Deneb
From the killing of animals, men draw meat to sustain themselves and skins to cover themselves;
but hunting is no longer sufficient to feed increasingly numerous and organised human
groups.
Throughout a few millennia, the meat that arrives with discontinuity is accompanied
by the milk of some herbivores captured and kept in captivity, and more and more intensively
the animals begin to be domesticated, reunited in flocks and bred.
The camps of the nomadic groups always on the trail of new game become semi-permanent
and seasonal, conditioned by the rhythm of pastoralism.
And who knows, perhaps the first migrations of the flocks towards richer pastures were
guided by a very bright star, which, although very approximate, indicated the North with
its intense white light: the alpha star of the Swan, Deneb, which in 15,000 B.C. was
less than 7° from the celestial pole.
Perhaps too far away to be taken as a safe reference.
It will be better a thousand years later, in 14,000 B.C., when only 1.7° from the pole
there will be the blue Swan Delta (magnitude.
+2.9).
And even better in 12,000 B.C., when 5° from the celestial north the bright Vega, the alpha
star of Lyra, will pass by.
10,000 years ago: between Hercules and the Dragon
At the end of the Palaeolithic, the dawn of Mesolithic saw the human species dedicate
itself with an increasingly expert hand to the cultivation of wheat, barley, wheat and
rice.
Agriculture became the main human activity, and with sheep farming it was the main source
of sustenance for increasingly numerous communities, now settled and organised in small villages.
Everyone's life depends on the correct preparation and the orderly execution of the sowing and
harvesting cycle, and this requires a deeper and deeper knowledge of the natural rhythms,
to which the productive ones must be adapted.
The Sun rises and sets, the Moon changes shape and brightness, some stars are always visible,
while others appear only at this or that sowing...
The man begins to look at the sky, asks himself questions, begins to put things in order,
identifies simple rules and passes them down from father to son.
Perhaps already in this time the figure of the man who more than others knows how to
"read the signs of heaven" is born, who notes in his mind things that others do not see
and who is asked for advice on how and when to prepare for a certain job.
nd while all this happens, the nearest star to the Pole is the yellow and rather weak
Eta Herculis (magnitude +3.4), which in 8000 B.C. is 6° away.
In those distant years the celestial North Pole keeps in fact at the border between Hercules
and the Dragon's head, in plaques without bright stars.
6000 years ago: Thuban (Alpha Draconis) and the origins of western civilization
The first permanent human settlements, fortified and organized as self-sufficient citadels,
date back to about 6000 years ago.
The best of these great transformations took place in the Middle East, where the first
real cities were born and the concept of central political power was established following
great aggregations of peoples and tribes.
When you think of ancient Egypt you think of the pyramids and their grandeur, but you
do not always remember the techniques of irrigation of the fields, and especially writing, mathematics,
astronomy with the construction of calendars.
So, thinking about the people of Mesopotamia, we must remember not only the invention of
the wheel, but also the introduction of writing, the discovery of "planets" (the "wandering
stars"), the first rudimentary forms of algebra.
And all this had its course in the Middle East, while in northern Europe people of which
we still know very little about placed in the ground enormous boulders, weighing a few
tons, roughly squared, aligning them for kilometres as at Carnac in Brittany, or arranging them
in concentric circles as at Stonehenge, to constitute useful alignments to indicate the
positions of the rising of the Sun at the solstices and equinoxes, as a sign of gratitude
to the Sun for its role as the main creator of the life cycle.
And while 5000 years ago (in 3000 B.C.) the time of the great Egyptian dynasties began,
the role of star closer to the North Pole passed to Thuban, the Alpha of the Dragon
(magnitude +3.7), which in 2800 B.C. would be only 6 minutes of arc away from the celestial
pole.
3000 years ago: Kochab (Beta Ursae Minoris)
Following the cultural heritage of the great Mesopotamian and Egyptian civilizations, the
great synthesis of the Mediterranean culture, the work of the Greeks, expert navigators
and enterprising merchants, founders of colonies from Italy to Asia Minor.
In Greece there is an extraordinary fusion of ethnic heritage and traditions that leads
to the epic of Homeric poems.
After a tortuous and dramatic succession of historical events, the first rudimentary forms
of democracy were created, the value of reason in man's life, in his choices and his relationship
with reality emerged; Philosophy was born, which posed the problem of explaining the
reasons for nature.
In this context, from a calendar instrument, astronomy became an instrument of cosmological
investigation and mathematics the language with which to express the perfection of a
symmetrical and eternal universe.
And to guide Ulysses' imaginary voyages (perhaps) throughout the Mediterranean sea there was
at that time a polar star called Kochab (Beta Ursae Minoris, magnitude +2.1), located 6.5°
from the celestial north.
Kochab still greeted as a polar star the ascending parable of the power of Rome and the birth
of Christ (8° away), but when the disintegration of the Roman empire in the 5th century A.D.
was coming to an end, the North Pole was by now equidistant from Kochab and Alpha Ursae
Minor, both at more than 9°; for this reason the Arabs, linked to their tradition that
assigned to Kochab the role of polar star, called Alpha Ursae Minoris, "Al ruccabah",
that is "the rascal", because they believed that this star was stealing to Kochab the
dignity that was due to it.
The return of Alpha Ursae Minoris to the North Pole and the last millennium of our history
Rome's empire has now been waning for centuries, and year after year, at the modest speed of
0.8° every century, alpha Ursae Minoris is getting closer and closer to the heavenly
region from where it left 260 centuries earlier.
It is 3.5° from the pole when Christopher Columbus ventured into the ocean to prove
that it is possible to reach the Indies by travelling in the opposite direction; and
only 2.6° in 1633, when Galileo was forced to abjure his beliefs.
In 1687, with his "Principia" Newton laid the foundations of a scientific revolution
by unifying the physics of the sky with that of the Earth, we go towards the age of "enlightenment",
that is, towards the triumph of "reason" over conventions and rigid schematism.
These are years of political and social transformations: the industrial revolution changes forever
the relationship between man and work.
In the scientific field, electricity and magnetism are unified and their applications accelerate
social change.
And Alfa Ursae Minoris, in the meantime, is less than 2° from the pole.
We have thus arrived in the era of technology, first with the general spread of electricity
and its applications, then with that of telecommunications (Marconi invents the radio in 1895 when the
polar is 1.2 ° away), and finally with the triumph of the microprocessor (designed in
1971, when the Polaris was at 51 arc minutes); but it is also the age of a science that,
together with solutions, also brings many doubts about its aims, earning the distrust
and disinterest of the common man.
We are in our days: the "North Star" that we know as such since our birth has reached
42 minutes of arc away.
And she went home.
In 80 years, in March 2100, it will reach the minimum distance of 27 arc minutes.
Something less than the angular diameter of the Full Moon.
To then start the tour again...