When two black holes merge, the resulting object rings like a struck bell, radiating gravitational waves that fade in a distinctive pattern called ringdown.
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It's some striking military technology.
Prehistoric art hidden in caves throughout southwestern Ireland for thousands of years could push back the timeline on the earliest human presence on the Emerald Isle by as much as 5,000 years, archaeologists say.
The remarkable discoveries may reveal a previously unknown chapter in the ancient history of human migrations across the British Isles during the Ice Age, and how they once traversed a portion of the landscape that is now sunken beneath the Irish Sea.
Reported by a team of researchers with the international Lost Land Bridge Project, the discoveries involve prehistoric markings located in eight caves in Ireland that could potentially date as far back as 15,000 years ago.
Some are engravings into the cave’s stone walls, while others are markings made with ochre and charcoal, and include lines traced along cave surfaces that appear to depict ancient animals that include deer, and extinct species such as mammoths.
If confirmed, Ireland’s long-hidden ancient artwork could dramatically shift past thinking about the earliest evidence of human arrivals on the island, which was previously believed to have occurred around 10,500 years ago.
If humans arrived in Ireland this early, it also raises an intriguing possibility: that they might have done so by traversing terrain that would only have been exposed amid the lower sea levels that prevailed toward the end of the last Ice Age.
This effect was due to the amount of water that was held within the vast glaciers near Earth’s poles, which, in addition to lowering sea levels, helped to reshape the geography of northwestern Europe during the Pleistocene.
Because of this, certain portions of the ancient landscape that are now submerged beneath ocean waters would have been exposed. Among these, one that stretched from modern Pembrokeshire in Wales and southeastern Ireland near Rosslare might have been used by ancient travelers who could have made their way to Ireland, leaving a record of their Ice Age journey on the walls of caves they used as shelter, according to Dr. George Nash of the University of Liverpool, who coordinated the project.
Nash believes this ancient crossing could have comprised a 46-mile-long area, where ancient nomadic people following natural subsistence patterns would have encountered vast expanses of grassland and vegetation, along with ample resources that included horses, bison, reindeer, mammoths, and other animals that these ancient hunter-gatherers were skilled at hunting.
Evidence from throughout Europe and other parts of the ancient world already shows that ancient hunter-gatherers were well-accustomed to following migrating animals and seasonal resources, and that the landscape could have provided a natural route westward.
Nash recently said that until now, archaeologists had relied mainly on accidental discoveries that suggested a human presence in Ireland by around 10,500 years ago. However, a growing number of archaeologists had begun to doubt that this was the period when humans initially arrived.
“We just weren’t looking hard enough, and not in the right places,” Nash said.
To determine locations where reliable evidence of an earlier human presence might be found, the researchers examined several features associated with prehistoric caves in southern Wales, where documented discoveries linked them to an early human presence.
Based on these characteristics, the team then relied on computer modeling to help them identify Irish locations that had similar features.
The team was assisted by Shane Diffily, an expert in caving, and digital mapping consultant Darren Lee, which allowed them to quickly narrow their search to just under 30 potentially promising caves throughout southwestern Ireland, according to Heritage Daily.
Of those locations, eight were found to contain what appeared to be various kinds of prehistoric rock art. The exact locations of those caves have not been released by the team, to protect the sites from vandalism, or potential looting—a major issue that has long complicated archaeological investigations.
Along with direct engravings into limestone surfaces and markings made with ochre and charcoal, researchers also discovered a few instances of what appear to be “finger flutings,” where soft surfaces such as clay or sediment were marked by ancient artists who dragged their fingers along such surfaces.
One of the most significant discoveries uncovered by Nash and the team appears to be a portion of a deer, and an image within one of the caves that appears to represent a mammoth. Examples like these could potentially help provide connections to similar examples known from prehistoric rock art that has been documented in Wales.
From those sites, some of the same prehistoric artists may have made their way across the ancient land bridge that was once available, leaving their markings at similar sites that once offered shelter as they arrived in Ireland.
The initial discoveries at the newly identified eight cave locations may represent only a small portion of the long-overlooked archaeological evidence throughout Ireland, which may document its earliest arrivals. Future investigations will likely focus on sites located near Wexford, Waterford, Cork, and other areas along routes that people may have followed as they made their way to southwestern Ireland.
As investigations continue, Nash and the research team say that reliable dating of the art will be an important next step toward determining how early these prehistoric artists might have arrived.
Once that testing is completed, it will help determine whether the timescales on the arrival of Ireland’s earliest human inhabitants will indeed be pushed back by thousands of years. If so, the newly uncovered cave art could offer an unprecedented look at the lives of those ancient hunter-gatherers who once traversed a landscape before it sank beneath rising ocean waters as Ice Age glaciers retreated.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
© Jason Gulley for The New York Times
A recent analysis of bones found in two separate underwater cave systems in South Australia has provided researchers with a new framework for investigating how animal remains, including those of extinct megafauna, came to rest in these submerged environments.
Well-preserved bones have often been found in submerged caves, but interpreting how they accumulated and what happened to them afterward has been difficult. Researchers have had limited tools for determining the environmental processes that alter remains over time.
The new study, led by Griffith University PhD candidate Meg Walker and Professor Julien Louys of the Australian Research Centre for Human Evolution, identifies physical, chemical, and molecular markers that can provide clues about the environmental conditions each specimen experienced. The findings were published in PLOS One.
With help from specialist cave divers from the Cave Divers Association of Australia, Walker’s team examined animal bones recovered from Green Waterhole and Gouldens Sinkhole, two underwater cave systems near Mount Gambier, South Australia. Gouldens Sinkhole reaches 63 meters deep through a nearly 30-meter-wide shaft.
The researchers used radiocarbon dating methods on 41 specimens and examined them at various scales, starting with a visual evaluation of spatial distribution and surface wear before progressing to portable X-ray fluorescence, scanning electron microscopy, and protein analysis. Using these techniques, the researchers identified chemical residue, signs of bacterial damage, and traces of ancient DNA. The group also identified changes associated with different preservation environments by comparing submerged bones with those recovered from nearby dry caves.
Light played an important role in some of the most noticeable changes to the bones. Near the cave entrances, where sunlight was available, algae and aquatic plants grew on the bone surfaces and left black biological stains, while cyanobacteria produced circular etchings and tunnels on the outer surfaces. Deeper within the caves, in areas where sunlight did not reach, the bones mostly stayed the same and retained their original characteristics.
This distinction is important because it shows that staining alone does not indicate that a bone was buried in sediment or fully submerged, as previously assumed. Instead, it shows that the bone was simply exposed to light.
Bones from the dry sections of the cave systems showed different patterns. In the absence of water and algae, land-based bacteria penetrated the bone from within, while plant roots created long grooves on the surface as they grew in search of nutrients. These features are distinct from those observed in submerged specimens.
The bones in the team’s study were not from ancient megafauna, belonging instead to cattle, kangaroos, emus, sheep, pigs, dingoes, rabbits, possums, quolls, and swamp rats. European settlers likely deposited the specimens in the caves after they arrived in the Mount Gambier region in the 1840s. DNA tests showed that one bone came from a Merino sheep.
The ultimate goal is to apply this framework to older material. Caves in the Mount Gambier region, such as Tank Cave and Englebrechts Cave, have yielded remains of Australia’s Pleistocene megafauna, including Diprotodon, a large marsupial similar in size to a rhinoceros, Thylacoleo carnifex, the largest known marsupial predator, and short-faced kangaroos that reached about 2 meters in height. Some of these fossils have remained undisturbed for more than 60,000 years.
Using Walker’s framework when looking at these specimens might help researchers understand how Australia’s megafauna fossils accumulated and could also provide a method for investigating factors such as human activity and environmental change that caused their extinction.
“This study has delivered the first framework for interpreting how megafauna fossils formed, survived, and changed in underwater caves,” Walker said. “It will provide archaeologists and paleontologists worldwide with a powerful new tool for reconstructing past environments and histories in these challenging conditions.”
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.
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