Space weather   The dark band in the green aurora pictured here is an example of a black aurora. A black aurora isn't an aurora at all; rather it is a lack of auroral activity. The black aurora is only visible to the naked eye if it is embedded in a region of diffuse (faint) aurora.   A wind of particles from the Sun called the solar wind buffets the blue funnel-shaped magnetosphere around the Earth. Last update: 30 August 2010