Researchers have made a groundbreaking discovery in Ukraine, unearthing stone tools that belonged to ancient humans over a million years ago. The findings, which come from a fresh analysis of the artifacts, reveal the earliest known presence of hominins in Europe. The study also suggests that the first humans to inhabit Europe migrated from east to west.

The Korolevo archaeological site, discovered in the 1970s, has provided archaeologists with a treasure trove of knowledge. Located near Ukraine's southwestern border with Hungary and Romania, the site has yielded an astonishing 90,000 stone tools. Initial dating indicated that the site had been used for more than 800,000 years.

To determine the accurate ages of the stone tools in the lowest archaeological layer, a team of researchers used a relatively new dating method. By analyzing radioactive particles inside mineral grains, produced by cosmic rays that rain down on Earth, they were able to establish a precise chronology. This method acts as a "cosmic clock" of human history, according to Roman Garba, lead author of the study published in the journal Nature.

By measuring the decay rate of two nuclides, aluminum-26 and beryllium-10, found in quartz grains from seven pebbles in the same layer as the stone tools, the researchers determined that the tools were 1.4 million years old. This discovery fills a significant gap in early hominin presence in Europe, both in terms of time and space.

Although it is unclear which species of early humans occupied the site at that time, the study suggests that it may have been Homo erectus. This extinct species is believed to be the earliest hominin to have left Africa and walk with a fully upright gait.

This discovery also sheds light on the migration patterns of early humans in Europe. The previously known earliest human fossils in Europe, found in Spain's Atapuerca site, date back 1.1 million years. Additionally, fossils discovered in Georgia near Dmanisi are thought to be 1.8 million years old. The now securely dated stone tools from the Korolevo site indicate the presence and movement of hominins from east to west.

Briana Pobiner, a paleoanthropologist at the Smithsonian National Museum of Natural History, states that the finding suggests hominins may have been able to inhabit higher latitudes in northern Europe before colonizing southern Europe. However, more data from additional sites is required to fully understand whether this was a temporary incursion or a more permanent migration.

The study team also analyzed the climate and habitat of the area over the past two million years. They found that the age of the stone tools coincided with a warmer, interglacial period. The researchers also discovered evidence of a forest ecosystem through pollen data.

The accessibility of the Korolevo site made it appealing to ancient humans. Its proximity to the Tisza River, which leads to the Danube, provided a readily available source of hard rock for crafting stone tools.

Roman Garba and his colleagues hope to continue their investigation at Korolevo. However, the ongoing conflict in Ukraine has made it challenging to excavate and access artifacts from the site. Despite these obstacles, this unprecedented discovery boosts our understanding of early human history in Europe and sets the stage for further exploration in the future.