How Do We Know How Old This Rock Art Is?

Imagine stepping into a shadowy cave in Sulawesi, Indonesia. As the sunlight fades and your torchlight sweeps across the walls, you see something extraordinary. These are not random marks - they are ancient paintings, created by people who lived tens of thousands of years ago.

They depict animals and mysterious figures that blend human and animal traits. But these images are more than art. They speak of the early lives, beliefs, and imaginations of people long gone. As humans, we define ourselves as a species that tells stories - and these paintings are the earliest known evidence of that deep, defining trait. Finding out how old these ancient pictures are is like solving a huge mystery.

For a while, scientists figured out the age by analyzing the crusty calcium carbonate - known as "cave popcorn" - that formed over the paintings. They carefully cut out a piece of this crust and, back in the lab, micro-excavate the growth layers to create a fine powder.

This powder, made up of a mix of growth layers, is then subjected to a complex sequence of chemical processes. Using a method called uranium-series analysis, scientists can estimate an average age for when the crust began to form - but these deposits grow in complex ways, and mixing of older and younger material, or tiny bits of sediment, can still affect the results.

But scientists have a new, cooler tool, almost like a superhero gadget: laser-ablation uranium-series imaging. Instead of micro-excavating arbitrary layers of calcium carbonate, this method shines a tiny laser onto a polished cross section of the cave popcorn.

It lets them see right through the layers and map out the special elements that tell time, like uranium. This means they can be super precise, focusing the laser on the layer right next to the paint. They can also visualize and avoid any messy spots in the crust that could give a wrong age. Plus, it doesn't need much of the precious cave crust, making it less damaging.

Using this laser tool, scientists re-dated a famous painting at Leang Bulu’ Sipong 4. This painting shows human-like figures, some looking like half-animal beings (called therianthropes), interacting with pigs and small buffaloes, like a hunting story or a myth.

They used the laser on a newly found painting at Leang Karampuang cave. This one, found on the ceiling, shows a big pig and at least three smaller human-like figures right next to it, holding things and reaching out. It's a bit faded, but you can still see them interacting. The laser dating revealed something amazing: this painting is at least 51,200 years old! This makes it the oldest known example in the world of both realistic pictures and visual storytelling.

These findings from the caves of Sulawesi are a really big deal. They show that people were drawing detailed pictures of humans and animals and putting them together to tell stories much, much earlier than scientists used to believe. For a long time, people thought this kind of complex art mostly started later in Europe, but Sulawesi's caves prove that early humans (Homo sapiens) here had a rich culture of storytelling through pictures tens of thousands of years ago.