The strongest cosmic rays in history have struck Earth, with their source located somewhere nearby.

Scientists using the HESS observatory in Namibia have discovered that the Earth has been struck by the most powerful cosmic rays ever recorded. The fact that these cosmic rays possess extremely high energy suggests that their source is relatively close to the Solar System, as cosmic rays lose energy during their journey through space. The study has been published in the journal Physical Review Letters, reports Live Science.

Our planet, although protected by an atmosphere, is continuously bombarded by cosmic rays. To date, astrophysicists have limited information about these rays, but each new discovery brings us closer to unraveling their mystery.

Cosmic rays are streams of elementary particles that travel through space at nearly the speed of light. These cosmic ray particles carry immense energy.

It is believed that the sources of cosmic rays include:

• The Sun;
• supernova explosions that occur when a massive star dies;
• pulsars, or neutron stars that rotate very rapidly (these stars form after the death of massive stars);
• other unknown sources.

When cosmic rays collide with the Earth's atmosphere, they decay into a rain of particles that can be detected on the Earth's surface.

Using the ground-based HESS observatory, astrophysicists have identified cosmic rays with the highest energy ever observed. According to scientists, cosmic rays composed of electrons and their antimatter counterparts, positrons, had energies of up to 40 tera-electronvolts (TeV), which is 40,000 times greater than the energy of visible light.

When cosmic rays strike the Earth's atmosphere, they travel faster than the speed of light for a very short time. Just as an airplane flying faster than the speed of sound creates a sonic boom, a particle moving through the atmosphere faster than light generates a faint blue glow around it, known as Cherenkov radiation. This glow has allowed scientists to identify the highest energy cosmic rays in history.

As cosmic rays traverse space, they lose energy due to interactions with ordinary light and magnetic fields. The fact that these cosmic rays possess record energy indicates that they have traveled a relatively short distance on their way to Earth, suggesting that their mysterious source is located somewhere near the Solar System. However, what exactly created these cosmic rays remains a mystery.

It could be the remnant of a supernova, a dying Wolf-Rayet star, or a pulsar, say astrophysicists. Further research may reveal the potential source of the most powerful cosmic rays.

Astrophysicists believe that their source is within 1,000 light-years from us, which is a relatively short distance in cosmic terms. This is 100 times smaller than the size of our Milky Way galaxy.