SDO/NASA/swns
A huge coronal hole聽鈥� the large, darker area in the middle of this聽image聽鈥� appeared on聽the surface of the sun on 29聽January. Measuring more than 800,000 kilometres across, it was spotted by NASA鈥檚 Solar Dynamics Observatory spacecraft. Coronal聽holes are areas of cooler聽plasma that have a magnetic field structure that allows more charged particles to聽escape as solar winds.