Credit by Aurora Borealis ©
41,000 Years Ago, Auroras Blazed Near The Equator

41,000 Years Ago, Auroras Blazed Near The Equator

Northern and southern hemisphere residents have long been treated to spectacular displays of the northern lights, but an anomaly in the Earth's magnetic field 41,000 years ago brought auroras streaming out of the tropics. The Laschamp event, or Laschamp excursion, is a geomagnetic disruption that has caused auroras to appear near the equator.

Earth's magnetic field has been tipped, reducing the north and south poles' magnetic pulls to a fraction of their previous intensity.

What is Laschamp Event?

Per Civils Today, a geomagnetic event called the Laschamp excursion resulted in a brief reversal of the Earth's magnetic field 41,400 years ago near the conclusion of the Last Glacial Period To honor the settlement found in the French Massif Central, it was renamed after it.

Events that have been attributed to it include electrical storms, solar winds that formed auroras, Arctic air reaching the America's, and an increase in ice sheets and glaciers as well as drastic shifts in weather patterns.

During this period, the Earth was subjected to tremendous quantities of UV radiation. Megafauna and Neanderthals may have gone extinct at the same period that modern humans sought shelter in caves.

Auroras Moving Towards the Equator
Science Alert claimed that the magnetosphere's intensity during the Laschamp event plummeted to nearly 4 percent of present levels and tipped on its side. Studies in the past projected that the magnetosphere dissipated completely on Earth's dayside.

To test this idea, researchers gathered data from simulations of the interactions between the magnetosphere and the solar wind and fed those findings to a model that computed the location, form, and power of auroras in the past by examining the ionic pressure, density, and temperature.

Keterangan Gambar (© Pemilik Gambar)
arth is surrounded by a giant magnetic bubble called the magnetosphere, which is part of a dynamic, interconnected system that responds to solar, planetary and interstellar conditions. (Image credit: NASA)

They determined that the magnetosphere decreased around 3.8 times the radius of Earth during the Laschamp event and never dissipated totally. It influenced the poles formerly positioned in the north and south to relocate towards the equatorial latitudes, and so did the auroras.

The strength of the Earth's magnetic field only restored to its former strength after 1,300 years. Previous research have suggested that the era of the Laschamp event may have impacted changes in Earth's atmosphere that altered habitability on prehistoric Earth when the planet was subjected to an environmental crisis.

It's possible that the Laschamp event was seen by the first Australians.

In a study published in Quaternary Geochronology, researchers combined radiometric, geomagnetic, and climatic dating on a 270-ka sediment record from Lake Selina, Tasmania, and found that the earliest Australians may have seen the Laschamp event over 41,000 years ago.

According to Science Daily, researchers delved into a 270,000-year-old core from a Tasmanian lake and identified the record of the Laschamp event. Researchers emphasized that this is the first research since the 1980s.

They integrated radiometric, geomagnetic, and climatic dating to uncover the facts preserved in the core. They determined that ancient humans living in Tasmania may have witnessed the stunning auroras when Earth's magnetic field tilted when the north was south, and the south was north.


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