How well do we really know our ancestors? How much do we really know about our ancient past?
These are questions at the beating heart of modern-day exploration and archaeology… and thanks
to a game changing, technological revolution in the field, we’re quickly realizing that,
actually, there’s so much that we’re only just beginning to understand.
This is Unveiled, and today we’re discovering the
extraordinary science behind how LiDAR is unearthing ancient civilizations.
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As with so many cutting-edge technologies, LiDAR (or Light Detection and Ranging)
began life as a tool used in space exploration… at one time featuring in
the Apollo program in the early 1970s, as part of early efforts by NASA to map the moon. In short,
it’s a mapping technique whereby lasers are directed at the ground from the air,
via planes, helicopters, or drones. The lasers hit the ground and rebound back, with LiDAR tech able
to precisely measure the different distances at play, and therefore construct an accurate, 3D map
of the ground. Crucially, though, while operating at different wavelengths, LiDAR can penetrate
through things that might have otherwise obscured the picture. Things like leaves, tree canopies,
and dense vegetation, for example, which is why it’s become such a vital and ground-breaking
method in the exploration of Earth. The stereotypical image of an explorer
or archaeologist is perhaps one of an intrepid adventurer, slashing their way through thick
undergrowth in the middle of a distant jungle somewhere, in search of an ancient, legendary
trail or a treasure-laden lost city. But, while a lot of hands-on groundwork similar to that
is still carried out, times are certainly changing in the twenty-first century.
The paper maps, compasses and machetes of tradition do still have a place… but nowadays,
with any journey into the wilderness, there’s the potential for it to be significantly more planned
and deliberate. Thanks to LiDAR, archaeologists can be so much more informed
before they ever set foot onto an actual site. Over the 2010s, the technology really started to
take off. So far, it has been variously used to gain a better understanding of multiple Mayan
sites in modern-day Mexico… and scattered, ancient villages in the Amazon rainforest.
It’s also notably helped us to gain a clearer than ever picture of the famous Angor Wat
temple complex in Cambodia. In all cases, LiDAR maps have been produced from above,
and they’ve revealed to archaeologists that the extent of these ancient locations is usually far
greater than we had previously thought. It’s now known, for example, that Angor Wat was once but
one part of an even vaster ancient settlement, much larger than previously predicted, with LiDAR
images able to pick out the roads, waterways and homes that were once crowded around the temple.
Of course, the evidence for what LiDAR is now picking up has always been there, and perhaps
it would have been discovered by traditional exploration on foot, given enough time… but this
technology is fast-tracking us to near-instant results. It’s said that LiDAR can achieve in just
a few hours what it would otherwise have taken years of traditional groundwork to figure out.
As the images are captured from above by machines, it’s not as though LiDAR is a dangerous pursuit,
either. It’s exploration at a distance, yes, but it undoubtedly gets results.
Still, there are some that remain doubtful as to quite how heavily we should be relying
on this technology. And, to a certain extent, it still won’t replace classic, on-the-ground
exploration. What LiDAR can do is produce high-resolution images accurate to within around
twenty centimeters… but what it still can’t do is determine exactly what it is that it’s mapping.
For that, archaeologists still need to get up close, on the ground, in the thicket,
and in the mud. LiDAR is perhaps best used more like a contemporary guide, then, highlighting
areas of interest at a site that might otherwise have been easily overlooked, simply because the
jungle has become too overgrown, or the landscape has been too drastically altered in modern times.
The laser imaging means that now, rather than blindly searching for things that may
(or may not) be there, today’s explorer can confidently descend onto a location
that they know will yield results. It's one reason why it’s said (by some) that
we’ve recently entered into a new “golden age” for exploration. Although, on the one hand, it
would seem that because most of Earth is at least accounted for on maps, there isn’t a great deal
of our world left to discover… on the other, LiDAR technology is proving how we’ve only just begun to
scratch the surface of what’s really there. And, in just the first few years since its introduction
into archaeological study, it’s genuinely forcing us to rewrite whole periods of human history.
For example, our understanding has already changed regarding the Maya civilization. The
rise and fall of Mayan cities across a roughly three-thousand-year history up until the late
seventeenth century is reasonably well-known. There are numerous iconic sites and monuments
found across Central America, including the ruins of Tikal in Guatemala… and Chichen Itza
on the Yucatán Peninsula in Mexico. However, the early use of LiDAR over
some Mayan sites suggests that their scope may have also been hugely underestimated.
One of the first major LiDAR surveys in archaeology came in the year 2009,
as part of the ongoing Caracol Archaeological Project, led by the University of Nevada.
Caracol itself is an ancient Mayan city in modern-day Belize. It was first discovered in
1937, and there’s been a continuous and dedicated effort to excavate and explore it since around the
mid 1980s. But, in 2009, LiDAR was introduced and the picture of Caracol dramatically changed almost
overnight. Researchers were suddenly able to accurately map a far wider area than ever before,
as more than seventy square miles revealed itself to them - including new evidence of roads and
canals fanning out from the center. Before LiDAR, Caracol had been thought of as a reasonably
modest settlement… but after LiDAR, the reality was clear that Caracol was actually a large and
sprawling city. And, nowadays, the LiDAR maps inform so much about how Caracol is studied.
Of course, it’s not as though LiDAR is the only example of how technology is driving
modern exploration. We saw in another recent video how new-age techniques are
helping us to better understand what’s really inside the pyramids of Egypt, for instance,
with a process known as muon tomography allowing us to effectively see through pyramid walls,
into the hidden chambers inside. And, although there’s a lot of work left to do in our efforts
to map the seafloor, we’ve seen similar techniques used to improve our knowledge of the ocean, too,
allowing us to see through the waves at what’s really there. But, still, there’s little doubt
that LiDAR has kick-started an incredibly exciting time for archaeology, specifically. It’s leading a
new frontier for exploration, which is bringing to light whole buildings, landmarks and communities
that might’ve otherwise been lost forever. And so, in some cases, it really is prompting
us to seriously rethink our own past. Estimates on the maximum populations for sites like Angor Wat
and Caracol have increased, for example, partly as a result of LiDAR discoveries. And, in the bigger
picture, this could change our understanding of how whole civilizations worked… and of how
much of a wider impact they might’ve had. With LiDAR typically helping to detail the “outskirts”
of ancient cities, as well, archaeologists are producing a whole range of new maps from which
historians can draw new conclusions about how ancient societies were structured. How things
like wealth, work and trade were managed. And, suddenly, we’re connecting up ancient sites like
we’ve never done before… seeing them not just as seemingly isolated ruins, but as shared remnants
of a time and place that was once so much bigger. In archaeology, as in most things, modern
technology is driving change at a phenomenal rate. Thanks to lasers from the sky, we’re now scanning
whole jungles within hours and realizing the true extent of the ancient secrets they
hold. The contemporary explorer must still be ready to hack their way through dense forests,
wade through rivers, and scramble through caves… but they can now do it all knowing that technology
is lighting their way. And that’s how LiDAR is unearthing ancient civilizations.
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