The incoming blast of solar particles is worth getting excited about: we're in for a moderate (G2) geomagnetic storm starting around Saturday June 14, according to the NOAA's Space Weather Prediction Center.
A coronal hole is a region where the magnetic fields on the surface of the Sun weaken and open up. This allows the wind of charged particles that constantly gusts from the Sun out into the Solar System to escape more freely.
When it rushes past Earth, some of the particles become entangled in Earth's magnetic field, sometimes with stunning results.
The particles are whisked away on magnetic field lines to high latitudes, where they are dumped out into Earth's upper atmosphere. There, they interact with particles in the atmosphere to produce a dancing glow — the light of the auroras borealis and australis.