NASA space probes have detected an artificial “barrier” surrounding our planet. Made up of very low frequency radio waves that have leaked into space, this artificial “belt” is pushing out the Van Allen belt, which is working in our favour.
Man shapes and sculpts our planet, for the better or the worse. Take the Anthropocene, for example, the era in history which began when human activity started to have a significant global impact on the Earth’s ecosystem. This era, which follows the natural curve of evolution, had and continues to have a negative impact on the structure of the planet itself. It seems however that our activities have not limited themselves to impacting on the Earth, but are also modifying nearby space. But the good news is that contrary to our impact on the planet, our impact on space could work in our favour!
In 2012, NASA launched a mission in order to analyse the influence of the sun on the Earth and the nearby spatial environment, by studying the evolution of radiation belts that surround the Earth. Two probes were sent to investigate firstly the internal belt with extends from around 640 to 9,600 km above the surface of the Earth, and secondly the external belt which extends from 13,500 to 58,000 km above the surface. But recently, the Van Allen probes detected something rather odd when they were monitoring the activity of charged particles caught in the Earth’s magnetic field.
With further investigation, the researchers realised that a sort of artificial “barrier” or “belt” had kept these charged particles, which are dangerous for our planet, at a distance. They also discovered that this “barrier” had actively pushed out the Van Allen belts from the Earth over the past number of decades. The lower limits of radiation flux are thus further away than they were in the 1960s.
This “barrier” is said to be artificial, as it is the result of human activity. It is made up of very low frequency radio waves, and in other words, thanks to these waves, we now have anthropogenic (or man-made) space weather. Although we don’t use these waves in our daily lives, they are used in numerous engineering, scientific and military operations. With frequencies between 3 and 30 kilohertz, they are in fact ideal for sending coded messages over long distances, or deep underwater. These signals were never intended to be sent anywhere other than around the Earth, but certain waves visibly “escaped” into space and stayed there for long enough to form a giant protective bubble. According to measures taken by the probes, the outer limits of this artifical “bubble” correspond very precisely with the inner limits of the Van Allen belt.
While this protective bubble is probably the most positive influence that man has had on the space surrounding our planet, it certainly isn’t the only one. We have in fact been leaving our imprint since the 19th century, and in particular over the course of the past fifty years with the first nuclear trials. These explosions created artificial radiation belts which have led to major damage to several satellites. Other anthropogenic impacts on the space environment include chemical release experiments or high frequency wave heating of the ionosphere.