The Millennium Sundial
and
"A Walk through Time"
(2001)

Dr Francis Thackeray

Human Origins and Past Environments Programme
Transvaal Museum

A Millennium Sundial, engraved in granite, has been installed at the Sterkfontein Caves in the Cradle of Humankind World Heritage Site. The sundial project was announced at a function held at the Sterkfontein Heritage Lodge http://www.sterkfonteinlodge.com on March 22, 2001, associated with a "Walk through Time". This project serves to promote public awareness of the changing diversity of life within long periods of time, and has financial support from the Ministry of Arts, Culture, Science and Technology. The project was proposed by Dr Francis Thackeray and Sandy Dacombe as an initiative of the Transvaal Museum and the Southern African Science Communication Network (SASCON) in 1998, and has been endorsed by several organisations, including the University of the Witwatersrand, the South African Museums Association, the Geoscience Museum, the Royal Society of South Africa, the South African Mint, and the Hartebeeshoek Radio Astronomy Observatory (HARTRAO).

The Millennium Sundial

The sundial was designed by Dr Mike Gaylard of the Hartebeesthoek Radio Astronomy Observatory, specifically for the latitude and longitude of Sterkfontein. A movable stick known as a "gnomon" is placed vertically on the engraved granite surface, and the time for a particular day of the year can be read from the position of the shadow cast by the gnomon, across the "Time Line". In order to give an accurate time of day, the position of the gnomon for any particular day changes in the course of a year, taking into account seasonal changes associated with the shape of the earth’s orbit around the sun, and the tilt of the earth’s axis. The gnomon is moved to a new position each day, along the figure-of-eight path known as an "analemma" or "Date Line", which allows for these effects.
This contrasts with traditional sundials, such as those used by ancient Greeks and Romans, which have a fixed gnomon that casts a shadow across a time-line. They usually have to be "corrected" by adding or subtracting up to 16 minutes from the time shown on the sundial, depending on the time of year. Such calibration is not required for the Millennium Sundial at Sterkfontein as this is provided by its analemma. Full details of the Millennium Sundial are available in the document prepared by Dr Gaylard of HARTRAO, or from http://www.hartrao.ac.za/other/sundial/sundial.html

                                                                      A Walk Through Time

Fifteen granite slabs have been engraved with images of various fossils or examples of art, representing the changing diversity of life, as part of South Africa’s rich palaeontological and cultural heritage. The slabs of granite are arranged in a chronological sequence from the time of the "Big Bang" to the present, which is represented by the ever-changing shadow of the sundial.

                                                      Homo sapiens and rock engravings

Rock engraving is an African tradition that goes back at least 10,000 years. Archaeologists have discovered rocks with engraved images in cave deposits that can be dated, using associated charcoal (from ancient wood-fires) to establish their age, by means of radiocarbon dating. The oldest dated examples of rock engravings from South Africa are from Wonderwerk Cave (Thackeray et al, 1981).
In the "Walk through Time" at Sterkfontein, there are two granite slabs with engraved copies of South African rock art which date to the Holocene, a period which spans the last 10,000 years. One engraving shows an eland (Taurotragus oryx) which is recognised as having been a symbol of power among prehistoric communities, notably those of the Khoisan (Lewis-Williams, 1981, Lewis-Williams and Dowson, 1989). The eland image in the "Walk through Time" is based on a rock engraving from the Magaliesberg not far from Sterkfontein.

A second example of South African rock art is based on a scene recorded in the Eastern Cape Province, showing two people (Homo sapiens, the species to which we all belong). One person is at the bottom of a ladder, while the other is at the top. This example of rock art may be interpreted in more than one way. One suggested interpretation is that it represents "The Ascent of Man". However, this is based on western concepts and perceptions. If one explores African languages and beliefs, one can find a different interpretation, perhaps closer to the intention of the artists. Quite possibly the person at the top of the ladder is a metaphor for "being high", closely related to concepts associated with trance. Research undertaken on many examples of South African rock art has shown that at least some paintings and engravings are likely to represent perceptions associated with trance (Lewis-Williams 1981, Thackeray 1990).

The controlled use of fire at Swartkrans

In one engraved granite slab, reference is made to evidence for the use of fire at Swartkrans. At this site near Sterkfontein, Dr Bob Brain of the Transvaal Museum found bones of animals that had been burnt at high temperatures, in some cases exceeding 600 degrees Celsius. It has been suggested by Dr Brain and Dr Sillen (1988) that the burnt bones from Swartkrans represent the earliest evidence for the controlled use of fire, perhaps more than 1 million years ago. Without the controlled use of fire it would not be possible to have a rocket engine, and without a rocket it would not have been possible for representatives of Homo sapiens to walk upon the surface of the moon. In a sense, the controlled use of fire at Swartkrans, perhaps one million years ago, represents the small technological step that led to the giant leap associated with Neil Armstrong’s famous statement on the surface of the moon in 1969, when he said "That’s one small step for [a] man, one giant leap for mankind". Buzz Aldrin joined him on the lunar surface shortly afterwards. A plaque commemorating that historic event has been left on the moon, showing all the continents of the earth, with the words "We came in peace for all Mankind". A similar image of the continents of our planet has been incorporated in the "Walk through Time", recognising that prehistoric technology (including the controlled use of fire) and humanity itself, have African origins.

                                               
                                                                      "Mrs Ples"

"Mrs Ples" is the nickname for a fossilised skull of Australopithecus africanus, discovered in April 1947 at Sterkfontein by Robert Broom of the Transvaal Museum. "Mrs Ples", believed to be a distant ancestor of all humankind, lived in the Sterkfontein area about 2.6 million years ago. The rock engraving of "Mrs Ples" shown in the "Walk through Time" is based on a drawing by Dr Broom.

                                             
                                           "Mrs Ples" and the Andromeda Nebula

The engraving of "Mrs Ples" is juxtaposed with an engraving of galaxy called the Andromeda Nebula, a neighbour of our own galaxy, the "Milky Way". Light from the Andromeda Nebula takes about 2.6 million years to reach earth. Likewise, light from earth travels the same amount of time to reach the Andromeda Nebula. Whether or not there is any form of life in the Andromeda Nebula, light associated with images of "Mrs Ples" would be visible from that galaxy now, having travelled 2.6 million light years to get to that part of our universe.

                                               
                                                                    "Little Foot"

"Little Foot" is the nickname that was given to a collection of foot bones from Sterkfontein, 3.3 million years old, discovered by Dr Ron Clarke, Stephen Motsumi and Nkwane Molefe in 1997. The foot bones are part of a skeleton of Australopithecus, representing an adult that fell into the cave and was unable to get out (Clarke, 1998). The foot bones suggest that this individual could walk upright but was also an agile climber in trees, at a time when the Sterkfontein environment was much more wooded than today. As part of the "Walk through Time", a reconstruction of the foot has been engraved in granite, and shown actual size. Place your own foot next to the image of the "Little Foot" for comparison.

                                           
                                                              Massospondylus

Reptiles, including dinosaurs, survived for millions of years in warm environments in many parts of the world. One of the world’s earliest dinosaurs is Massospondylus, known from several parts of South Africa. Their fossilised remains are found in the Free State and in the Northern Province, in rocks that are about 200 million years old. The engraving of Massospondylus is based on a painting by C. Hunter (Cluver, 1978).

                                             Pangaea, Gondwana and Laurasia

About 200 million years ago, all continents of the world were joined together to form a single continent called Pangaea. After that time, the continents drifted apart. The northern continental masses were joined together to form Laurasia, but the southern continents (Africa, South America, Australia, Antarctica and even India) were linked together to form Gondwana (Cluver, 1978). As a symbolic re-unification of Gondwana and Pangaea, sands from all continents of the world have been brought together and form part of the Pangaean continental land mass embedded in granite in the "Walk through Time", corresponding to a period about 200 million years ago.

                                                                       Euparkeria

Euparkeria is the name for a reptile that represents a distant ancestor for dinosaurs and birds. Fossils of Euparkeria have been found in the foothills of the Drakensberg, in deposits that are about 220 million years old. It is similar in some respects to fossils that have been found in China, including Chinese fossils that have been interpreted as "feathered dinosaurs". At present there is no evidence that Euparkeria had feathers, but it is considered to be a distant relative of dinosaurs and birds. The engraving of Euparkeria is based on a painting by C. Hunter (Cluver, 1978).

                                                 

                                                                     Thrinaxodon

Thrinaxodon was a creature that lived in South Africa about 230 million years ago, representing a distant relative of all mammals. Thrinaxodon lived in the Karoo when conditions were much hotter and wetter than they are today. These small "mammal-like reptiles" are important as they represent a transition from reptiles to mammals (Broom, 1932).

                                                                       Lystrosaurus

Lystrosaurus was a mammal-like reptile that lived in the Karoo about 245 million years ago, belonging to a group called the Dicynodonts (Broom, 1932). These plant-eating creatures had only two teeth, in the upper jaw. They lived along the banks of wide meandering rivers. They dug spiral-shaped burrows in which they protected their young from carnivorous mammal-like reptiles. Major climatic changes occurred between about 250 and 245 million years ago, when conditions became drier and Lystrosaurus became extinct (Cluver, 1978).

                                                                      Coelacanth

The coelacanth is a fish that is known to have existed about 300 million years ago in the world’s oceans. Remarkably, similar forms have been found alive in the Indian Ocean, off the eastern shores of South Africa. Prof L.B. J. Smith described a coelacanth caught by fishermen in 1938, and recognised their affinities with prehistoric forms known from fossils. The engraving in granite in the "Walk through time" shows representations of fossil and modern coelacanths, using art work that was prepared by Natanya van Niekerk of the S.A. Mint, for part of a palaeontological series of gold coins marking important components of South Africa’s rich fossil heritage.

                                                       Rock with fossil bacteria

A rock from Mpumalanga, collected by Dr C.K. Brain, incorporates extremely small filamentous cyanobacteria, microfossils that are about 3,500 million years old. These fossils are among the earliest known forms of life from our planet (Schopf, J.W. 1983). This particular rock, black chert, comes from the Fig Tree Group (Swaziland Supergoup) of the Barberton sequence.

                                      Star Cluster 47 Tucanae and The Big Bang

It is thought that our universe began with a "Big Bang", more than 14,000 million years ago. Evidence for the "Big Bang" has been obtained from telescopes in South Africa and elsewhere in the world. One cluster of stars in the constellation of the Toucan, called 47 Tucanae by astronomers, includes stars that are about 14,000 million years old. It is one of several "globular clusters" that are neighbours of our galaxy. The image of 47 Tucanae in this "Walk through Time" is based on a photograph taken by a large South African telescope, using a reflecting mirror with a diameter of 188 cm. The photograph was taken by astronomers working at the Radcliffe Observatory in Pretoria about 50 years ago. The telescope has since been moved to Sutherland in the Karoo where it can be used together with other large telescopes, including the proposed South African LargeTelecope (SALT), away from bright city lights.

                                                     

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                                                                                                        Update: May 2001