The Earth was showered with electrons of record-high energies from a mysterious nearby source

Scientists have discovered for the first time the fact that the Earth is bombarded with electrons of sky-high energies. This could only happen in the case of a relatively close radiation source. Most likely it could be one or more neutron stars. It is impossible to establish the exact direction to the source – electrons easily follow the bends of magnetic lines and could have arrived on Earth from anywhere.

Artistic representation of a pulsar. Image source: NASA

The discovery was made by a group of European scientists based on data collected over 10 years of observations by the High Energy Stereoscopic System (HESS) observatory in Namibia. The share of electrons in the flow of cosmic particles barely reaches 1%. They are not easy to detect in noise and among other registrations. It should also be taken into account that particles arriving directly from space cannot be detected on Earth. They collide with atoms of atmospheric gases and cause a shower of their debris, which is recorded by instruments and this makes it possible to restore a picture of what actually arrived.

Electron energies are traditionally low—on the order of hundreds of gigaelectronvolts. Electrons with an energy of 40 TeV were detected in the HESS observatory data, which is trillions of times higher than normal. It’s important to note that the source of these high-energy particles couldn’t be too far away, since electrons quickly lose energy as they travel through the Universe.

Calculations showed that the particles were emitted by an unknown object within several thousand light years from Earth. Neutron stars, compact objects with extremely strong magnetic fields (pulsars, to be more precise), are capable of such an action. Since the exact direction to the source cannot be established, one can only guess whether it was one star or several.