Did A Comet Impact Push Humans Into Technological Overdrive?

About 14,500 years ago, Earth began transitioning from its cold, glacial self to a warmer interglacial state. However, partway through this period, temperatures suddenly returned to near-glacial conditions. This abrupt change (known as the Younger Dryas period) is believed by some to be the reason why hunter-gatherers started forming sedentary communities, farming, and laying the groundwork for civilization as we know it – aka. the Neolithic Revolution.

For over a decade, there have been scientists who have argued that this period was the result of a comet hitting Earth. Known as the Younger Dryas Impact Hypothesis (aka. the Clovis Comet Hypothesis), the theory is largely based on ice core samples from Greenland that show a sudden global temperature change. But according to a new study by a research team from the University of Edinburgh, archaeological evidence may also prove this hypothesis correct.

The Younger Dryas period takes its name from a species of flower known as Dryas octopetala. This plant is known to grow in cold conditions, and became common in Europe during the period. Because of the way it began abruptly – roughly 12,500 years ago – and then ended just as abruptly 1200 years later, many scientists are convinced it was caused by an external event.

Göbekli Tepe, structures A-D of the site, located in southern Turkey. Credit: Wikipedia Commons/Teomancimit

For the sake of their study – which was recently published in the journal Mediterranean Archaeology and Archaeometry under the title “Decoding Göbekli Tepe With Archaeoastronomy: What Does the Fox Say?“- the team found an astronomical link to the stone pillars at Göbekli Tepe. Located in southern Turkey, this archaeological find is the oldest known temple site in the world (dated to ca. 10,950 BCE).

This site, it should be noted, is contemporary with the Greenland ice core samples, which are dated to around 10,890 BCE. Of the sites many features, none are more famous than the many standing pillars that dot the excavated grounds. This is because of the extensive pictograms and animal reliefs that decorate these pillars, which include various representations of mammal and avian species- particularly vultures.

Pillar 43, which is also known as the “vulture stone”, was of particular interest to archeologists, as it is suspected that its representations (associated with death) could have been intended to commemorate a devastating event. The other images, they ventured, were meant to depict the constellations, and that their placement relative to each other accorded to the positions of the then-known asterisms in the night sky.

This theory was based on images they took of the site, which they then examined using the planetarium program stellarium 0.15. In the end, they found that the images bore a resemblance to constellations that would have been visible in 10,950 BCE. As such, they concluded that the temple site may have been an observatory, and that the images were a catalog of celestial events – which include the Taurid meteor stream.

Wall pillars with three animal symbols in series. Part a) is pillar 2 from Enclosure A, while part b) is pillar 38, Enclosure D. Credit: Travel The Unknown

As they state in their study:

“We begin by noting the carving of a scorpion on pillar 43, a well -known zodiacal symbol for Scorpius. Based on this observation, we investigate to what extent other symbols on pillar 43 can be interpreted as zodiacal symbols or other familiar astronomical symbols… We suggest the vulture/eagle on pillar 43 can be interpreted as the ‘teapot’ asterism of our present-day notion of Sagittarius; the angle between the eagle/vulture’s head and wings, in particular, agrees well with the ‘handle’,‘lid’ and ‘spout’ of the teapot asterism. We also suggest the ‘bent-bird’ with downward wriggling snake or fish can be interpreted as the ‘13th sign of the zodiac’, i.e. of our present-day notion of Ophiuchus. Although its relative position is not very accurate, we suggest the artist(s) of pillar 43 were constrained by the shape of the pillar. These symbols are a reasonably good match with their corresponding asterisms, and they all appear to be in approximately the correct relative locations.

Similarly, they suggest that a carved circle at the center of pillar 43 could be interpreted as the Sun. They call this image the “date stamp” because it can be seen as communicating a specific date by indicating which part of the zodiac the Sun was in at the time of carving. By comparing the age of the site (based on carbon dating) to the apparent position of the Sun, they found that it was consistent with the Summer solstice of 10,950 BCE.

Of course, the team fully acknowledges that an astronomical interpretation is by no means the only possibility. In addition to the possibility of them being mythological references, they could also be representations of hunting or migration patterns. It’s also entirely possible they were not meant to convey any specific meaning, and were merely a description of the local environment, which would have been rich in flora and fauna at the time.

Pillar 43, Enclosure D, also known as the Vulture Stone of Göbekli Tepe. Credit: Martin B. Sweatman and Dimitrios Tsikritsis

In addition, the way vultures are commonly featured could be an indication that the site was a burial ground. This is consistent with iconography found at the archaeological sites of Çatalhöyük (in central, southern Turkey) and Jericho (in the West Bank). During the time period in question, Neolithic peoples were known to conduct sky burials, where the bodies of the deceased were left out in the open for carrion birds to pick over.

In such practices, the head was sometimes removed from the deceased and kept (for the sake of ancestor worship). This is consistent with one of the characters on Pillar 43, which appears to be a headless human. However, as the team go on to explain, they are confident that the connection between the site’s images and the Taurid meteor stream is a plausible one.

“[O]ur basic statistical analysis indicates our astronomical interpretation is very likely to be correct,” they write. “We are therefore content to limit ourselves to this hypothesis, and logically we are not required to pursue others.” And of course, they acknowledge that further research will be necessary before any conclusions can be made.

Despite the availability of other (and perhaps more plausible) explanations, one has to admit that the astronomical theory is appealing. Civilization as we know it being a response to a meteor impact, and ancient people cataloging it in their stone carvings. It’s got a real Deep Impact meets 2001: A Space Odyssey feel to it!

Further Reading: MAA Journal

Ancient Astronomical Calendar Discovered in Scotland Predates Stonehenge by 6,000 Years

A team from the University of Birmingham recently announced an astronomical discovery in Scotland marking the beginnings of recorded time.

Announced last month in the Journal of Internet Archaeology, the Mesolithic monument consists of a series of pits near Aberdeenshire, Scotland. Estimated to date from 8,000 B.C., this 10,000 year old structure would pre-date calendars discovered in the Fertile Crescent region of the Middle East by over 5,000 years.

But this is no ordinary wall calendar.

Originally unearthed by the National Trust for Scotland in 2004, the site is designated as Warren Field near the town of Crathes. It consists of 12 pits in an arc 54 metres long that seem to correspond with 12 lunar months, plus an added correction to bring the calendar back into sync with the solar year on the date of the winter solstice.

Diagram...
A diagram of the Warren Field site, showing the 12 pits (below) and the alignment with the phases of the Moon plus the rising of the winter solstice Sun. Note: the scale should read “0-10  metres.” (Credit: The University of Birmingham).

“The evidence suggests that hunter-gatherer societies in Scotland had both the need and sophistication to track time across the years, to correct for seasonal drift of the lunar year” said team leader and professor of Landscape Archaeology at the University of Birmingham Vince Gaffney.

We talked last week about the necessity of timekeeping as cultures moved from a hunter-gatherer to agrarian lifestyle. Such abilities as marking the passage of the lunar cycles or the heliacal rising of the star Sirius gave cultures the edge needed to dominate in their day.

For context, the pyramids on the plains of Giza date from around 2500 B.C., The Ice Man on display in Bolzano Italy dates from 3,300 B.C., and the end of the last Ice Age was around 20,000 to 10,000 years ago, about the time that the calendar was constructed.

“We have been taking photographs of the Scottish landscape for nearly 40 years, recording thousands of archaeological sites that would never have been detected from the ground,” said manager of Aerial projects of the Royal Commission of Aerial Survey Projects Dave Cowley. “It’s remarkable to think that our aerial survey may have helped to find the place where time was invented.”

The site at Warren Field was initially discovered during an aerial survey of the region.

Vince Gaffney professor of Landscape and Archaeology at University of Birmingham in Warren Field, Crathes, Aberdeenshire where the discovery was made.
Vince Gaffney, professor of Landscape and Archaeology at University of Birmingham in Warren Field, Crathes, Aberdeenshire where the discovery was made. (Credit: The University of Birmingham).

The use of such a complex calendar by an ancient society also came as a revelation to researchers. Emeritus Professor of Archaeoastronomy at the University of Leicester Clive Ruggles notes that the site “represents a combination of several different cycles which can be used to track time symbolically and practically.”

The lunar synodic period, or the span of time that it takes for the Moon to return to the same phase (i.e., New-to-New, Full-to-Full, etc) is approximately 29.5 days. Many cultures used a strictly lunar-based calendar composed of 12 synodic months. The Islamic calendar is an example of this sort of timekeeping still in use today.

However, a 12 month lunar calendar also falls out of sync with our modern Gregorian calendar by 11 days (12 on leap years) per year.

The familiar Gregorian calendar is at the other extreme, a calendar that is strictly solar-based.  The Gregorian calendar was introduced in 1582 and is still in use today. This reconciled the 11 minute per year difference between the Julian calendar and the mean solar year, which by the time of Pope Gregory’s reform had already caused the calendar to “drift” by 10 days since the 1st Council of Nicaea 325 AD.

Artist’s conception of the Warren Field site during the winter solstice. (Credit: The University of Birmingham). Credit: The University of Birmingham
Artist’s conception of the Warren Field site during the winter solstice. (Credit: The University of Birmingham). Credit: The University of Birmingham

Surprisingly, the calendar discovered at Warren Field may be of a third and more complex variety, a luni-solar calendar. This employs the use of intercalary periods, also known as embolismic months to bring the lunar and solar calendar back into sync.

The modern Jewish calendar is an example of a luni-solar hybrid, which adds an extra month (known as the 2nd Adar or Adar Sheni) every 2-3 years. This will next occur in March 2014.

The Greek astronomer Meton of Athens noted in 5th century B.C. that 235 synodic periods very nearly add up to 19 years, to within a few hours. Today, this period bears his name, and is known as a metonic cycle. The Babylonian astronomers were aware of this as well, and with the discovery at Warren Field, it seems that ancient astronomers in Scotland may have been moving in this direction of advanced understanding as well.

It’s interesting to note that the site at Warren Field also predates Stonehenge, the most famous ancient structure in the United Kingdom by about 6,000 years. 10,000 years ago would have also seen the Earth’s rotational north celestial pole pointed near the +3.9th magnitude star Rukbalgethi Shemali (Tau Herculis) in the modern day constellation of Hercules. This is due to the 26,000 year wobble of our planet’s axis known as the precession of the equinoxes.

The precession of the north celestial pole over millenia. (Credit: Wikimedia Commons graphic under a Creative Commons Attribution 2.5 Generic license. Author: Tau'olunga).
The precession of the north celestial pole over millennia. (Credit: Wikimedia Commons graphic under a Creative Commons Attribution 2.5 Generic license. Author: Tau’olunga).

The Full Moon nearest the winter solstice also marks the “Long Nights Moon,” when the Full Moon occupies a space where the Sun resides during the summer months and  rides high above the horizon for northern observers all night. The ancients knew of the five degree tilt that our Moon has in relation to the ecliptic and how it can ride exceptionally high in the sky every 18.6 years. We’re currently headed towards a ‘shallow year’ in 2015, where the Moon rides low in relation to the ecliptic. From there, the Moon’s path in the sky will get progressively higher each year, peaking again in 2024.

Who built the Warren Field ruins along the scenic Dee Valley of Scotland? What other surprises are in store as researchers excavate the site? One thing is for certain: the ancients were astute students of the sky. It’s fascinating to realize how much of our own history has yet to be told!

 

 

Podcast: Archaeoastronomy

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The Sun, Moon, stars and planets are visible to the unaided eye, and so they have been visible to astronomers since before recorded history. Some of the earliest records we do have tell us what the ancient astronomers thought about the heavens, and how they used the changing night sky in their daily lives.

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Archaeoastronomy shownotes and transcript.

Astronomy Without A Telescope – Indigenous Australian Astronomy

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Eta Carinae is a massive binary system – of which the dominant member is an eruptive luminous blue variable star. The system’s last significant eruption – also known as the ‘great outburst’ – made Eta Carinae briefly the second brightest star system in the night sky after Sirius over the period of 1837 to 1845, after which it faded again. The great outburst left behind the Homunculus Nebula – and also left an impression on the indigenous Aboriginal people of Australia who observed it at that time.

Hamacher, with research interests in Australian archaeoastronomy – and Frew, an astrophysicist with research interests in the light curves of variable stars over long time periods, have collaborated on a paper which draws on historical records to build a case that the Boorong people of northwest Victoria incorporated the observation of Eta Carinae’s great outburst into their oral traditions.

This is of general interest as the only known observation of the Eta Carinae outburst by indigenous people – and of particular interest to Hamacher to support his assertion that Australian Aboriginal oral traditions are dynamic and evolving – and often incorporate transient astronomical events.

The Boorong clan apparently no longer exists as an entity and much of their traditional knowledge may have been lost. However, William Stanbridge published records of his encounters with them around 1860, particularly detailing their astronomical knowledge. His records include Aboriginal star names and stories associated with them – against which he either wrote down the relevant European star name or otherwise at least indicated the general vicinity of the star in question.

Of particular interest here is the star named Collowgullouric War by the Boorong – described as a ‘large red star in Rober Carol, marked 966’ by Stanbridge. In Boorong oral tradition at that time, Collowgullouric War was the wife of War – which Stanbridge directly identified as the star Canopus – and which today we consider the second brightest star in the night sky.

There are other examples of husband and wife pairings in Aboriginal astronomy – where the stars are generally closely associated in the sky and of similar apparent magnitude. Stanbridge noted Collowgullouric War as the third brightest star in a list that included Sirius as brightest, Canopus as second brightest and Alpha Centauri (or Rigil Kent) as fourth brightest. Today we would agree with most of that statement, except that Alpha Centauri is the third brightest star – and what the heck is Collowgullouric War?

The reference “large red star in Rober Carol, marked 966” refers in short-hand to a now-defunct constellation Rober Carolinum – and 966 is almost certainly a designation drawn from one of the first southern sky star catalogues, produced by La Caille in 1763. Lac 966 is actually the Carina nebula, while the Eta Carinae star is Lac 968 – but since it’s unlikely Stanbridge had his own copy of the rare La Caille catalogue, there is the possibility of a transcription error. And, in any case, in referring to a star associated the Carina Nebula, it seems reasonable to assume he really meant Eta Carinae.

Argo Navis (the ship Argo) was one of Ptolemy's 48 constellations - since split into the modern constellations Vela (the sails), Puppis (the stern) and Carina (the keel). Another now-defunct constellation, Robur Carolinum (the Oak of King Charles) introduced by Edmond Halley, also overlies this region of the sky. Around the 1840's, Eta Carinae (red arrow) might have been classified as a star of the Robur Carolinum constellation - but is now considered part of the Carina constellation. Canopus (or Alpha Carinae) is the large, bright star to the right of the drawing of the ship's rudder. Credit: Johannes Hevelius' star catalogue Firmamentum, circa 1690 - as sourced from Hamacher and Frew. And... for reasons unknown, Hevelius did his star catalogues from the point of view of an outsider looking in, so this map is kind of back the front. The same approach is used on the flag of Brazil - for reasons unknown. What a long caption this is.

So for a brief period of a decade or so – Eta Carinae rivalled Canopus in brightness, during the period of its variable brightening from 1837 to 1845.

On this basis, it is reasonable to assume that an indigenous people with an interest in the night sky would certainly have noted the Eta Carinae outburst – and might well have developed a story based on its close association with the similarly bright star Canopus, which was present in the sky nearby.

It remains to be discovered what other southern sky events the Indigenous Australians may have gained a privileged view of during their 40,000 year colonization of the Australian continent.

Further reading: Hamacher and Frew An Aboriginal Australian Record of the Great Eruption of Eta Carinae