People have long been fascinated by the stars. From Stonehenge to the Great Pyramids of Giza, archaeologists and astronomers suspect many ancient monuments may have links to the night sky as crude observatories or as star markers. Now, new research suggests that ancient observatories may be much more common than archaeologists once thought—and many may have doubled as tombs for the dead.
Scattered across Europe are Neolithic structures known as “passage graves.” Dating back about 6,000 years, these tombs are built underground with a single long passageway leading back to the surface. These gravesites can be found all across Europe, from Scandinavia to Portugal, and according to new research, these long passageways may have also been intended to act as early telescopes, Clare Wilson writes for the New Scientist.
Recently, a group of archaeologists led by Fabio Silva of the University of Wales Trinity Saint David have been investigating a group of passage graves uncovered in Portugal. Researchers have long suspected that Neolithic humans led their lives in accordance to the appearance of certain stars in the sky: for example, the annual return of the star Aldebaran in early April’s dawn skies may have marked the time of year when some ancient humans led their livestock to new pastures for summer grazing, Adrienne LaFrance reports for The Atlantic. Intriguingly, Silva says that many of the passages his group has studied are oriented in such a way that they might have allowed a person sitting inside an early glimpse at Aldebaran’s rise.
While modern telescopes work by magnifying light through a series of lenses, these passageways are much cruder. Instead, the long, dark passageways might have worked as simple telescopes by focusing on a single part of the sky while blocking out most of the light from the rising sun. As the viewer’s eyes would have been adapted to the darkness, it could have made it easier to pick out faint stars, reports Nicola Davis for The Guardian.
But why would there be a live person sitting inside a tomb? The researchers think that these sites were also used for rites of passage—youth could have been left inside the graves with the remains of their ancestors.
“Imagine a young boy forced to spend the night in the passage—probably scared to death,” Silva tells New Scientist. “In the morning he would see this star rise days before the rest of his tribe. That may have been presented as secret knowledge.”
Silva and his colleagues are currently attempting to test this hypothesis in the lab by placing subjects in a similar structure to the passage graves and seeing if they can pick out the image of a faint star in twilight conditions, much as an ancient person would have experienced one of these tombs. Silva believes these tunnels may have been related to specific stars seen at certain times of year, but others argue it may just mark how important stargazing was to our ancestors, Davis writes.
“Whether these really were were the reasons why the passage tombs were originally built is hard to say for sure,” astronomer Marek Kukula of the Royal Observatory Greenwich tells Davis. “But this kind of ‘archaeoastronomy’ highlights the fact that human beings have always been fascinated by the stars and that sky-watching has had an important role in human society for millennia.”
Researchers may never fully understand our ancestors’ intentions in building these ancient structures, but if these stone tunnels did act as simple telescopes, it goes to show just how our species’ fascination with the stars has inspired remarkable feats of ingenuity throughout our history.