Our planet is surrounded by two such radiation belts (& a temporary third one), the inner belt stretches from around 640 to 9600 km (400 to 6000 miles) above Earth’s surface while the outer belt occupies an altitude of nearly 13500 to 58000 km (8400 to 36000 miles).
In 2017, the Van Allen Probes detected something very strange as they monitored the activity of charged particles caught within Earth’s magnetic field, these dangerous solar discharges were being kept cornered by some type of low frequency barrier.
When researchers investigated, they found that this barrier actively pushing the Van Allen Belts away from Earth over the past few decades and now the lower limits of the radiation streams are literally further away from us than they were in the 1960s.
A certain sort of transmission called Very Low Frequency (VLF) radio communications, became much more common now than in the 60s and the team at NASA confirmed that they will influence how & where certain particles in space move about.
“A number of experiments & observations have found out that under the proper conditions, radio communications signals in the VLF frequency range can actually affect the properties of the high-energy radiation environment around the Earth,” said one among the team, Phil Erickson from the MIT Haystack Observatory in Massachusetts, back in 2017.
One of the most common use of VLF signals is to communicate with deep sea submarines but because their large wavelengths can diffract around large obstacles like mountain ranges, they’re also used to achieve transmissions across tricky terrain.
It was never the intention of VLF signals to go anywhere aside from on Earth but it seems that they have been leaking into the space surrounding our planet and have lingered long enough to make an enormous protective bubble.
When the Van Allen Probes compared the location of VLF bubble to the bounds of Earth’s radiation belts, they found what initially seemed like a stimulating coincidence. “The outward extent of the VLF bubble corresponds almost exactly to the inner fringe of Van Allen radiation belts,” said NASA.
But once they realized that VLF signals can actually influence the movement of charged particles within these radiation belts, they realized that our unintentional man-made barrier has been progressively pushing them back.
While their protective VLF bubble is probably the best influence we humans have made on the space surrounding our planet, it’s never the only one, we’ve been making our mark on space since the 19th century and particularly over the past 50 years when nuclear explosions were all the rage.
The research was published by Science Space Reviews.