A NASA spacecraft watches as a huge 'hole' in the Sun's atmosphere rotates into view

A coronal hole on the Sun, as seen by a NASA spacecraft between Dec. 2 and 9, 2016. (Source: NASA SDO/Helioviewer.org) Over the past week, NASA's Solar Dynamics Observatory spacecraft watched a massive coronal hole rotate into view as the Sun spun on its axis. Click on the screenshot above to bring up a video I posted to my Youtube channel showing all the action as seen by SDO between December 2nd and 9th. Such holes occur in areas of the solar atmosphere, called the corona, where the Sun's magnetic field is open to space, rather than closed in on itself. This allows charged particles to stream out at high speed, lowering the density and temperature of material in the parts of the corona where this occurs. The result: When the Sun is viewed in x-ray wavelengths, as it is above, we see a dark region, or "hole," in the ...