3. Solar storms?
Solar storms — deluges of energetic particles from the sun — do happen, usually waxing and waning in cycles that last roughly 11 years. When these charged particles collide with Earth, they can trigger auroras and damage satellites and power lines, although not really inflicting any lasting harm, Yeomans said.
There are accounts of a solar "super-storm" slamming into Earth in 1859. Although that caused relatively little damage back then, there are concerns that such a storm might cause far more harm now that our world is more dependent on electronics.
Yet, there is no evidence that such a super-storm will happen on Dec. 21 of next year, Yeomans said.