Science Buzz

Giant ‘hole’ in sun is 50 earths wide

Sun with its coronal holeNASA’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.

Coronal holes, normally formed over the sun’s poles and lower latitudes, are areas within the sun’s outermost layer (corona), which are lower-density and cooler. This, plus the weakened magnetic field, lets the plasma and charged particles that make up the corona stream out more easily in a solar wind at up to 800 km/sec, kindling a days-long geomagnetic storm upon hitting Earth. The phenomenon 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: the glowing auroras that form in the night sky over the northernmost reaches of the planet grow much brighter and can even extend much farther south than usual.