Stonehenge in Wiltshire, southern England, is a mysterious place that speaks of a culture and political–religious authority of which we know almost nothing, probably motivated by belief in long-dead gods whose supposed presence was, at the time, undoubtedly considered to be “all around”. This is much as theists of all religions assert of their god or gods today. Who these people were, remains one of the great mysteries, as does how they moved such massive stones into place to build a stone circle with extraordinary precision, and how they transported them over long distances long before the domestication of the horse.
We know they were not the later Welsh-speaking Celts, who did not arrive in Britain until around 1,000 BCE — some two millennia after construction of Stonehenge began. Those Celts replaced the Beaker culture, which itself had replaced the Neolithic farming communities who first built the monument. Construction began around 3,000 BCE, initially as a bank-and-ditch enclosure with a circle of wooden posts. This was later replaced, around 2,500 BCE, by a circle of massive sarsen stones sourced locally from the nearby Salisbury Plain, with the smaller bluestones brought from the Preseli Hills in south-west Wales. The so-called “altar stone” was added last. Its precise origin remains unresolved, with conflicting evidence suggesting either north-west Scotland or west Wales as its source.
While the question of where most of the stones came from has largely been resolved, what remains is the long-standing puzzle of how they were transported using only human labour. The motivation was clearly strong enough to justify the immense effort and manpower involved, and the fact that it was human effort that moved them has now been established beyond reasonable doubt by the falsification of an alternative hypothesis — namely, that the stones were carried to Salisbury Plain by a passing glacier during the last Ice Age.
The refutation of this idea provides a neat example of how science tests and falsifies hypotheses, though it will no doubt unsettle creationists who cling to the absurd belief that the entire history of the Earth can be compressed into a timescale of just 6,000–10,000 years. The work was carried out by two researchers from Curtin University in Perth, Western Australia, and relied on dating zircon crystals — a highly accurate method for determining the age of rock formations, as regular readers of this blog will know — along with apatite grains, which similarly exploit the radioactive decay of uranium isotopes into stable lead isotopes.
