The Earth is protected by a powerful magnetic field that helps keep us and other life forms safe from ejections from the Sun. These ejections launch charged particles and cosmic rays, but the magnetic field helps deflect a vast majority of these to help us avoid radiation.
On the other hand, it was recently found that there was a crack in the Earth's magnetic field, which brings up the question: are we still safe from the charged particles and cosmic rays that are always bombarding us from the Sun?
The short answer is yes, but the reason why is a little more confusing. Although the cracked magnetic field was still very much effective at repelling charged particles away from us, the trick it had to deal with were cosmic rays leaking through the cracks.
Most of these were probably absorbed by the Earth's magnificent atmosphere before reaching us, but still, this crack allowed more than usual to penetrate the planet, so it's definitely something experts will need to keep an eye on.
Importantly, strong enough ejections from the Sun can knock out lots of electronics on Earth, including the satellites that orbit the planet, airplanes that fly in the sky, and even the technology on the ground. Keeping ourselves safe from these kinds of bombardments is essential to life, so understanding the magnetic field is important in itself.