What is the piece of shit this "Rigidity" I always try to calculate....

Rigidity of a particle is its ability to "punch through" magnetic fields(Yes, in space we have sooo fucking big magnetic field. Galactic one)
Rigidity is the ratio of the particle’s momentum(kinda speed*mass, except photon ofc) to its charge. The greater the particle’s energy (momentum) and the smaller its charge, the harder it is to deflect its trajectory.

In other words, the particle doesn’t care about the magnetic field: it keeps flying as if nothing can stop it. Rigidity is the parameter that determines whether a cosmic ray particle can penetrate magnetic fields and, for example, reach Earth.

Earth's magnetic field acts like a huge protective screen, deflecting charged particles. Its strength is most noticeable at the equator, where the field lines are nearly horizontal, and weakest near the poles. This means that particles with low rigidity are deflected and don’t reach Earth, especially in equatorial regions. High-energy particles with greater rigidity, however, overcome the magnetic field and reach the planet’s surface. This is why polar regions are more frequently exposed to cosmic rays, leading to phenomena like auroras(I wrote about here already, just scroll below...long scroll...).

For astronauts and satellites, the picture is much less pleasant🥲
High-energy cosmic rays pose a serious threat: they can penetrate spacecraft walls, damage equipment through radiation, and expose crews to harmful radiation.

Earth’s magnetic field protects us, but in open space, this "shield" is absent, and cosmic radiation becomes a significant challenge for future missions to the Moon and Mars.

You might ask:
"But doesn’t the magnetic field fail to protect us from super high-energy particles?"

And I will say "there’s no real need for protection in those cases, because such particles are incredibly rare: about one particle per km² per year. It’s the low-energy(even auroras particles are low energetic) are abundant and far more problematic, but we are protected(unlike astronauts).

Next time, I’ll tell you more about this.