Between 4 and 6 September, NASA’s Solar Dynamics Observatory spacecraft captured extreme ultraviolet images of a large, well-developed “hole” in the Sun’s corona followed by the formation of another, larger hole nearby. Coronal holes are dark, cooler regions of the Sun’s outer atmosphere associated with open magnetic field lines where electrically charged particles making up the solar wind readily stream out into space. Brighter areas in this view are regions where magnetic activity is strong.
The Sun emitted a mid-level solar flare, peaking at 8:33am BST on 24 August 2015. NASA’s Solar Dynamics Observatory, which watches the Sun constantly, captured the image of the event shown here. Although harmful radiation from such a flare cannot pass through Earth’s atmosphere, intense flares can disturb the atmosphere in the layer where GPS and communications signals travel.
Our Sun is a volatile star, producing giant clouds of solar particles called coronal mass ejections. Now scientists may finally have a tool to predict the magnetic configuration of a CME from afar, enabling forecasters to give utility grid and satellite operators a day’s advance warning to protect their systems.
Among the most feared events in space physics are solar eruptions — massive explosions that hurl millions of tons of plasma, gas and radiation into space. These outbursts can be deadly to astronauts and when these eruptions reach the magnetic field that surrounds the Earth, the contact can create geomagnetic storms that disrupt cell ‘phone service, damage satellites and knock out power grids.