Enormous Sunspot, Raises Concerns , After Rapidly Doubling in Size.br 'Newsweek' reports that a massive, earth-facing sunspot has doubled in size over 24 hours and has raised br concerns about a potential earth-bound solar flare.br Sunspots form over areas of the sun br where strong magnetic fields exist. .br These tangled magnetic fields can suddenly br reorganize themselves, releasing an explosion br of light and radiation in the form of a solar flare.br On June 20, NASA's Solar Dynamics br Observatory revealed how the sunspot br had significantly grown over the course of a day.br 'Newsweek' reports that the massive sunspot has the potential to send an M-class solar flare at Earth.br As of June 21, the National Oceanic br and Atmospheric Administration's Space Weather br Prediction Center had not yet issued a solar flare warning.br Solar flares can interfere with br radio communications networks br and navigation systems on Earth.br M-class flares are actually quite common br and tend to cause moderate, short-lasting br radio blackout events.br X-class flares are the strongest type of solar flare and only occur about once every 11 years.br An X20 flare would be capable of causing br a total high-frequency radio blackout for several br hours on the sun-facing side of Earth.