Reference the post immediately above -


Washington (AFP) - Back in 2012, the Sun erupted with a powerful solar storm that just missed the Earth but was big enough to "knock modern civilization back to the 18th century," NASA said.

The extreme space weather that tore through Earth's orbit on July 23, 2012, was the most powerful in 150 years, according to a statement posted on the US space agency website Wednesday.
http://news.yahoo.com/earth-survived...222404357.html


Also

Are nuclear reactors vulnerable to solar storms?

http://www.washingtonpost.com/blogs/...CTae_blog.html