Voyager probes have detected a completely new type of electron explosion outside the solar system.
This is the first time that a spacecraft has discovered this “unique physics” and could allow new breakthroughs in our understanding of the “interstellar medium,” or interstellar space.
NASA launched two Voyager spacecraft more than 40 years ago, with the goal of flying to the far reaches of our solar system. They have now gone further, reaching interstellar space, exploring the gaps between the stars, giving us the first glimpses of what might be the case in that mysterious region.
The recent discovery of the spacecraft – using data from both Voyager 1 and 2 – had them capture batches of electrons that it had never previously detected. They found that the electrons in cosmic rays are accelerated by shock waves that arise from major volcanic eruptions on the sun, and then are launched into space.
The electron bursts travel before the shock waves that throw them into space. Electrons travel at nearly the speed of light, and they accelerate along magnetic field lines.
Soon enough, the low-energy electrons arrive, sometimes taking days to do so. Then the spacecraft detects the shock waves themselves, sometimes a month later.
The shock waves themselves come from coronal mass ejection, which are masses of hot gas and energy that are thrown from the sun at nearly a million miles per hour. The Voyager spacecraft is now so far away even at this speed, which takes a year to discover.
Says Don Gurnett, Iowa professor emeritus of physics and astronomy and corresponding author of the study.
“We identified with these cosmic ray instruments the electrons that were reflected and accelerated by the interstellar shocks propagating outward from the active solar events at the sun. This is a new mechanism.”
Scientists now hope to be able to use this discovery to better understand both shock waves and the radiation itself.
This, in turn, could help guide considerations when sending astronauts on long missions to the moon or Mars, where they will be exposed to much more cosmic rays than we are exposed to on Earth.