The extreme phenomena occur when fast-moving particles from outside the solar system called cosmic ray electrons are affected by shock waves triggered by erupting stars. The electrons then proceed to speed-up further along cosmic magnetic field lines.
Professor Don Gurnett of the University of Iowa, said: “The idea that shock waves accelerate particles is not new.
“[But] we detected it in a new realm: the interstellar medium, which is much different than in the solar wind, where similar processes have been observed.”
Both Voyager spacecraft incredibly remain operational despite spending 43 years hurtling through distant space.
Each of the NASA-built unmanned space probes regularly beam-back data from the few instruments still functioning.
Electron bursts result from coronal mass ejections which see unimaginable quantities of super-hot plasma spewing into space, creating shock waves rippling through the solar system.
These shock waves consequently accelerate fast-moving cosmic-ray electrons, which are charged particles originating from distant supernovas.
The cosmic rays are then sped-up even more along magnetic field lines between stars in the interstellar medium.
These magnetic field lines gradually accelerate the cosmic rays to almost light speed, almost 670 times faster than the solar shock waves that first pushed them.
US-based space agency NASA has monitored the shock waves travelling at approximately 1 million mph (1.6 million kmh).
The University of Iowa team wrote: “Physicists believe these electrons in the interstellar medium are reflected off of a strengthened magnetic field at the edge of the shock wave, and subsequently accelerated by the motion of the shock wave.
“The reflected electrons then spiral along interstellar magnetic field lines, gaining speed as the distance between them and the shock increases.”
Voyager 1 and Voyager 2 both detected the electron bursts within days of their acceleration, and the twin probes later detected slower, lower-energy plasma wave oscillations through the interstellar medium resulting from the electron bursts.
The pair of probes also discovered evidence of the original solar shock wave almost a year after the event occurred.
This lag time is due to the spacecrafts’ now extreme distance from the Sun – 14.1 billion miles and 11.7 billion miles from our star respectively.
To put this into perspective, the average distance between the Earth and Sun is roughly 93 million miles – also known as one Astronomical Unit (AU).
Astronomers eventually hope to better comprehend how shock waves and cosmic radiation originate from flaring stars.
Such solar outbursts can be responsible for radiation that poses risks for astronauts on the International Space Station (ISS) and even Earth.
Particularly violent eruptions can also threaten satellites in low-Earth orbit and vital communication infrastructure and power lines.