They survived ice ages and hunted mammoths; so why did the Neanderthals suddenly disappear? Now a physicist blames something in the sky

Neanderthals have long puzzled scientists. These ancient relatives of modern humans thrived across Europe and parts of Asia for hundreds of thousands of years. But around 40,000 years ago, they disappeared, just as Homo sapiens spread across the same regions. What really caused their extinction remains one of human evolution’s biggest mysteries.

Now, a new and unusual theory suggests that space weather, not climate, competition, or disease, may have played a decisive role.

A recent study by Dr. Agnit Mukhopadhyay, a space physicist from the University of Michigan, proposes that a powerful cosmic event known as the Laschamp excursion might have played a part in the Neanderthals' decline. The findings were published in the journal Science Advances.


The Laschamp event occurred about 41,000 years ago, when the Earth’s magnetic poles temporarily flipped. During this brief reversal, the planet’s magnetic field, which normally protects us from cosmic radiation, dramatically weakened for several centuries.

Mukhopadhyay argues that this weakening may have exposed the Earth’s surface to much higher levels of ultraviolet (UV) and cosmic radiation, particularly in some parts of the world.

Radiation as a Hidden Killer?

The core of the hypothesis is that Neanderthals, already living in small, isolated populations, may have been more vulnerable to this radiation than Homo sapiens. The study claims that Homo sapiens had tighter clothing, used red ochre as UV protection, and took shelter in caves helping them survive the radiation. Neanderthals, in contrast, might have lacked these protections.

Computer simulations in the study even show that auroras, a sign of increased solar activity, might have been visible across much of the world during this time, proof, the author argues, of the heightened radiation environment.

While the theory is bold and imaginative, many experts are skeptical.

Researchers José-Miguel Tejero and Montserrat Sanz Borràs, writing for The Conversation, point out that the idea rests on shaky archaeological evidence.

For example, it assumes that Neanderthals didn’t wear fitted clothing. While it’s true that no sewing needles have been found at Neanderthal sites, there is clear evidence that they processed animal hides and likely wore functional garments using other techniques, such as tying hides with leather cords or splinters.

In fact, genetic studies of lice suggest that humans, possibly including Neanderthals, were already wearing clothes over 200,000 years ago. The absence of needles doesn’t prove the absence of clothes.

The study also claims that Homo sapiens used red ochre as sunblock. While experiments show that ochre can somewhat block UV rays, this claim is also disputed. Ochre was widely used by both Neanderthals and modern humans, often for symbolic or cosmetic reasons. There is no solid evidence that either group used it primarily for sun protection.

Neanderthals are known to have used ochre for over 100,000 years. In one example, a painted scallop shell found in a Neanderthal cave in Spain shows their symbolic use of pigments long before Homo sapiens arrived in Europe.

Most scientists believe that multiple factors caused the Neanderthals’ disappearance. These include, interbreeding with Homo sapiens (evident in modern DNA), smaller populations that were more vulnerable to decline, limited long-range hunting tools, unlike the projectile weapons used by sapiens, Changing climate, and possibly, competition for resources.

In this broader context, Mukhopadhyay’s theory appears too narrow. Critics note that there is no archaeological evidence of a sudden, global collapse of Neanderthal populations tied to the Laschamp event. If radiation were such a major factor, it would have also harmed Homo sapiens populations living outside caves in sunny Africa, which doesn’t seem to have happened.

A Caution Against Oversimplification

The Neanderthal story is complex. These early humans were not primitive brutes. They developed tools, built shelters, made symbolic objects, and survived in extreme climates for hundreds of thousands of years. They even lived through earlier magnetic reversals, such as the Blake event 120,000 years ago.

Mukhopadhyay’s theory adds an intriguing piece to the puzzle, but it’s far from conclusive.

So, did a shift in Earth’s magnetic field doom the Neanderthals?

Probably not. While the Laschamp event may have had some environmental impact, there’s no strong evidence that it caused Neanderthal extinction. The theory suggests that the disappearance of Neanderthals was likely due to a mix of climate, biology, and human interaction.