It is often said that where there is smoke, there is fire. This was the premise followed by researchers at the Institute of Sciences of the Weizmann Institute of Sciences. They describe an innovative, cutting-edge technique they have created and used to find non-visual signs of fire dating back at least 800,000 years, one of the earliest known signs of the use of fire, in a recent paper published in Proceedings of the National Academy of Sciences.
The newly created method could help us understand the beginnings of human history , our most fundamental traditions, and our penchant for experimentation and innovation.
Since when do we make fire?
Previously, to determine if a fire had ever broken out, researchers relied on finding direct evidence (such as traces of charcoal) and analyzing bones for atomic changes, writes Science ‘s Michael Price. But while both methods are effective, such evidence is rarely found at ancient sites.
Not all fires leave such obvious traces, especially after hundreds of thousands of years . Now, using artificial intelligence (AI) to detect the subtle ways extreme heat deforms a material’s atomic structure, scientists have uncovered the potential presence of a nearly 1 million-year-old fire with dozens of supposedly burned objects buried in it. an archaeological site in Israel ( Evron Quarry in western Galilee). During a series of excavations that took place at the time, archaeologists excavated 14 meters and discovered a wide variety of animal fossils and Palaeolithic tools dating from between 800,000 and a million years ago, making it one of the oldest in Israel. If the technique proves reliable, the findings could shed light on when, where and why humans first learned to harness flame.
“This evidence for fire is from a very early period in human development and suggests that a million years ago human contact with fire might have been more common than we thought,” said Michael Chazan, a professor in the department of anthropology at the U of T’s College of Arts and Sciences and co-author of the study. “In addition, this method allows us to detect traces of fire where they could not be seen before.”
The “kitchen hypothesis,” the working theory, holds that the use of fire played a crucial role in human development, allowing hominins not only to keep warm, make sophisticated tools, and defend themselves against predators, but also to develop cooking ability. Cooking meat not only kills pathogens, it increases efficient protein digestion and nutritional value, paving the way for brain growth. The key to our evolution.
Using artificial intelligence
The researchers devised software to look for subtle patterns that would have taken scientists centuries to find on their own. Using a technique called ultraviolet (UV) Raman spectroscopy, which measures the absorption of ultraviolet light, AI could reliably differentiate between burned and unburned pieces of modern flint and even reveal the temperatures at which they burned. They applied their method to 26 flint tools, mostly small cutting edges, that had been excavated in the 1970s at Evron Quarry. The advantage of AI is that it can find hidden patterns at a multitude of scales.
The results revealed that the tools had been heated to a wide range of temperatures, some exceeding 600°C. Furthermore, using a different spectroscopic technique, they analyzed 87 faunal remains and found that the tusk of an extinct elephant also exhibited structural changes as a result of heating. The presence of hidden heat suggests that our ancient ancestors, like the scientists themselves, would be experimenting with the flame.
“If we use this method on archaeological sites that are one or two million years old, we might learn something new ,” the authors note.
Referencia: “Hidden signatures of early fire at Evron Quarry (1.0 to 0.8 Mya)” by Zane Stepka, Ido Azuri, Liora Kolska Horwitz, Michael Chazan and Filipe Natalio, 13 June 2022, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2123439119
