Scientific journeys into the past
Kibbutz Sde Boker in the Negev is a popular place of pilgrimage. It is here that Israel’s founding Prime Minister David Ben-Gurion is buried, having chosen to spend his twilight years in the puritan wilderness rather than the fleshpots of the metropolis. We have come on a history trail, but stretching back far beyond modern Israel, far beyond Jews, Israelites or the land of Canaan. Before we reach the kibbutz, we turn off, past the unperturbed ibex nibbling on the rocks, and descend into the wadi below.
Our destination, along the bank of an ancient riverbed, is Boker Tachtit, an excavation site where you can see flints exposed in the rock — tools left by its inhabitants from tens of thousands of years ago. My guide, Elisabetta Boaretto, Dangoor Professor of Archaeological Science at the Weizmann Institute, takes me to another site a few hundred metres away, where she points to a layer of charcoal in the yellow rock — like chocolate filling in a wafer biscuit — the remnant of a prehistoric barbecue.
What has brought the scientists here is the search for evidence of the first modern humans, homo sapiens, who emerged out of Africa some 50,000 years ago.
“We are in the corridor between Africa, Asia and Europe,” Professor Boaretto says. “Most probably, the ancient humans passed through this region and left their sign in different sites.”
While scientific research can open a path to the future, it can also help to shape our understanding of the past. Weizmann has become a leader in the field, thanks in particular to D-Reams, that is the Dangoor Research Accelerator Mass Spectrometer, named after one of its sponsors, the late Anglo-Jewish philanthropist, Naim Dangoor.
The machine, the only one of its kind in Israel, is the “instrument that has allowed us to date archaeological material that we recover and excavate,” Professor Boaretto explains.
An assemblage of cylinders and cabinets that fills a large room, it measures the decay of carbon-14 in organic material, enabling accurate dating for up to 50,000 years.
The archaeological remains are taken from the site, carefully treated at the institute to remove contaminants and loaded as tiny pinhead-sized samples of graphite into a cathode to be fed to the machine.
Israel’s dry climate has proven a godsend to archaeologists. One of the seven species of produce
Professor Elisabetta Boaretto associated with the Land of Israel can be especially valuable to research. The humble olive pit, which can lie preserved in the hard ground for thousands of years, may be witness to human habitation, though a single olive on its own is not enough — “It could have been moved by rodents from one level to another, a cluster of olive pits is much more typical,” says Boaretto. One project the Weizmann team worked on showed that fava beans were cultivated in the Galilee around 10,000 years ago — the earliest known cultivation of the crop. Another demonstrated that the Philistines reached Israel more than a hundred years earlier than previously thought, in the 13th rather than the 12th century BCE, which reopened the question of what brought them there.
Exploring the prehistoric past may not be controversial, unless you happen to believe that the world was literally created 5,780 years ago. But it is when archaeology digs into the biblical period that its findings become more sensitive.
In 2004, a discovery of the remains of a large tower at Gihon Spring, the main water-supply for Jerusalem in olden days, prompted great excitement. It was originally dated to the middle Bronze age
Pride and joy of Weizmann Institute archaeology: the Dangoor Research Accelerator Mass Spectometry lab in the 17th century BCE and the City of David website identified it with the fortress King David conquered from the Jebusites to establish his capital in Jerusalem. As the Bible records, “David took the stronghold of Zion; the same is the city of David” (II Samuel 5:19).
But subsequent analysis of the soil under the stones by the Weizmann team undermined the fortress of Zion theory, as they dated it to many hundreds of years later, to 900 BCE – after the time of King David or his son Solomon (according to traditional dates for their reigns).
Israel Finkelstein, professor emeritus at Tel Aviv University and one of Israel’s best-known archaeologists, said the dating did not rule out an earlier origin for the tower – it could have been an older structure which underwent later repairs.
Not that Finkelstein is a champion of King David. He disputes the biblical account of David’s monarchy, arguing instead that Jerusalem was just a small village at that time and his united kingdom a mythical past projected from a later period.
The battle over David — and whether there is any scientific evidence to back up the biblical story — remains one of archaeology’s keenest contests. But you can be sure that as the soil of Israel yields its clues, and the scholars debate their significance, the particles will be whizzing around the Weizmann spectrometer for many years to come.