Sunscreen Might Have Helped Early Humans Outlive Neanderthals

upstart writes:

Sunscreen might have helped early humans outlive Neanderthals:

Sunscreen may have been essential to the survival of prehistoric humans at a time when Neanderthals were dying out, according to a recent study by researchers at the University of Michigan.

European Homo sapiens may have protected themselves from harmful solar radiation using ochre: a natural mineral, known for its rich yellow, red and brown hues, that can act as a sunscreen when applied to the skin.

This was at a time - between 41,000 and 39,000 years ago - during a period of unusual activity in Earth's magnetic field that left early humans at particular risk of Sun damage.

The magnetic field is generated by electrical currents from the Earth's core, creating an invisible halo that protects us against cosmic radiation and charged particles from the Sun.

The North and South poles act as the north and south of the magnetic field - but that's not fixed. It is possible for the poles to wander from their geographical positions and for the strength of the magnetic field to change.

The last time this happened was around 40,000 years ago, called the Laschamps excursion. Scientists at the University of Michigan recently developed models to estimate how this excursion would have changed the Earth's magnetic field, and calculate any knock-on effects.

"During the Laschamps event, the magnetic poles shifted away from true north," Dr Agnit Mukhopadhyay, lead author and U-M research affiliate in climate and space sciences and engineering, told BBC Science Focus.

"This movement, coupled with a notable weakening of the magnetic field, resulted in an expanded auroral zone and increased atmospheric penetration by energetic particles, such as solar energetic particles and cosmic radiation."

The scientists estimated that the Earth's magnetic field would have reduced to approximately 10 per cent of its current strength, and that the North Pole would have drooped down near the Earth's equator, during the Laschamps excursion.

As a result, auroras - spectacular light shows that are usually only visible near the poles - would have been visible all over Europe and into northern Africa.

Their calculations also show that Homo sapiens and Neanderthals would have been much more vulnerable to the harmful effects of ultraviolet light.

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