NASA’s orbiting Solar Dynamics Observatory has mapped an enormous coronal hole – a gap in the Sun’s outer layer and magnetic field, which is the size of 50 Earths and is releasing an extra-fast solar wind in Earth’s direction.

The gap in the Sun’s magnetic field lets out a stream of particles travelling at up to 800 kilometres per second, kindling a days-long geomagnetic storm upon hitting Earth.

Coronal holes normally form over the Sun’s poles and lower latitudes, more often when the Sun is at a less active point in its 11-year cycle.

They are areas within the Sun’s outermost layer, called its corona, which are lower-density and cooler – that, plus the weakened magnetic field, lets the plasma and charged particles that make up the corona stream out more easily in a solar wind.

If aimed towards Earth, it could result in a geomagnetic storm, a phenomenon that can affect power and navigation for satellites orbiting the Earth as well as radio communication.

Another side effect of a geomagnetic storm is enhanced northern lights.