This week, NASA’s Solar Dynamic Observatory (SDO) observed a dark, gaping hole – as wide as 50 Earths – in the outermost layer of the Sun and its magnetic field. Officially known as a coronal hole, the massive gap is letting a jet of fast-moving particles spew out into space.
Coronal holes like the one we see this week typically form over the poles and in lower latitudes during less active points in the Sun’s 11-year cycle. Cooler, denser regions within the Sun’s outer layer plus a weakened magnetic field allow plasma and charged particles within the Sun’s interior to leak out, generating a high-speed solar wind. Coronal holes are not unusual, and can appear at different areas and with varied frequency throughout the Sun’s cycle.
Coronal holes appear invisible to the human eye and you should never try to observe the Sun without the proper safety equipment as you can cause serious damage to your eyes. The new image was captured in the wavelength of extreme ultraviolet light (193 Angstroms) and then colorized bronze.
The solar wind can fuel geomagnetic storms, ultimately producing the beautiful auroras we see on Earth. Auroras typically occur in the northernmost and southernmost regions of the planet, lighting up the night sky in a brilliant array of colors. During a geomagnetic storm, the auroras can be much brighter than normal and can also be visible in more areas. For example, this past week the National Oceanic and Atmospheric Administration (NOAA) reported that auroras could potentially be visible as far south as Iowa, Pennsylvania and Oregon.
NASA partnered with citizen scientists to create a program for tracking auroras called Aurorasaurus. The mobile app and website allows you to learn all about auroras, including how they form and how you can track them.
Geomagnetic storms are not harmful to humans, but can adversely affect infrastructures such as power grids and even communication and navigation systems. Geomagnetic storms are tracked and ranked according to their intensity on a scale from 1-5. This particular solar storm was reported to be responsible for power outages and fires at several telegraph system facilities across Europe and North America.
Earlier this year, NASA teamed up with NOAA to launch the Deep Space Climate Observatory (DSCVOR) that will essentially act as a tsunami buoy in space, warning us of impending geomagnetic storms. When the satellite is fully operational, it will provide an hour of advanced warning time, enabling us to prepare communication systems and infrastructures (such as power grids) in order to minimize any hazardous effects.