The Sun, at the moment, is highly active as it moves to the peak in its current solar cycle and the star in our solar system can be dramatic depending on its mood. One such dramatic event happened three years ago.
April 17, 2021, was supposed to be a period of solar calmness, but then a brilliant flash erupted and an enormous cloud of solar material exploded from the star in our solar system. But what was different about this explosion was the high-speed protons and electrons that were hurtled in outer space.
These particles were hurtled at such high energy that they were nearing the speed of light. They struck five spacecraft on guard in the inner solar system, and now we know what happened.
It was the first time such high-speed protons and electrons – called solar energetic particles (SEPs) – were observed by spacecraft.
In a paper published in the journal Astronomy & Astrophysics, astronomers said that the explosion struck five different spacecraft at well-separated locations between the Sun and Earth, as well as in the orbit of Mars.
The analysis of data revealed that that different types of potentially dangerous SEPs can be blasted into space by different solar phenomena and in different directions, causing them to become widespread.
The storm was picked up by BepiColombo spacecraft, a joint mission of ESA (the European Space Agency) and JAXA (Japan Aerospace Exploration Agency), Nasa’s Parker Solar Probe, and ESA’s Solar Orbiter, which were on opposite sides of the flare. Next in line to be hit were Nasa’s two Solar Terrestrial Relations Observatory (STEREO) spacecraft, STEREO-A, followed by the Solar and Heliospheric Observatory (SOHO) and Nasa’s Wind spacecraft.
Solar energetic particles (SEPs) are high-energy charged particles, primarily protons and electrons, that are emitted from the Sun during solar events such as solar flares and coronal mass ejections (CMEs). These particles can travel through space and, when they interact with the Earth’s magnetosphere and atmosphere, can have various effects.
When SEPs reach the Earth, they can pose potential hazards to astronauts in space, as well as to satellites and other spacecraft. Additionally, the interaction of these particles with the Earth’s magnetosphere can lead to geomagnetic storms, affecting power grids, communication systems, and navigation systems on Earth.
“SEPs can harm our technology, such as satellites, and disrupt GPS. Also, humans in space or even on airplanes on polar routes can suffer harmful radiation during strong SEP events,” Nina Dresing of the Department of Physics and Astronomy, University of Turku in Finland, said in a statement.
The study revealed that the high-energy particles were not blasted out by a single source all at once but propelled in different directions and at different times potentially by different types of solar eruptions.
The team concluded that the electrons were likely driven into space quickly by the initial flash of light – a solar flare – while the protons were pushed along more slowly, likely by a shock wave from the cloud of solar material, or coronal mass ejection.
Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
