Pictured above are the orbits of the over 1,000 known Potentially Hazardous Asteroids (PHAs). These documented tumbling boulders of rock and ice are over 140 meters across and will pass within 7.5 million kilometers of Earth -- about 20 times the distance to the Moon. Although none of them will strike the Earth in the next 100 years -- not all PHAs have been discovered, and past 100 years, many orbits become hard to predict.
"if it had hit, we would still be picking up the pieces," said daniel baker, of the laboratory for atmospheric and space physics at the university of Colorado. "i have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did. if the eruption had occurred only one week earlier, Earth would have been in the line of fire."
with colleagues from nasa and other universities, baker has been studying the disaster that wasn't. if the coronal mass ejection (cme) had hit the Earth, it would have disabled "everything that plugs into a wall socket".
there would have been major disruption to all satellite communications and electrical fluctuations that could have blown out transformers in power grids. most people wouldn't have been able to turn on a tap or flush a toilet because urban water supplies largely rely on electricity.