A perfect storm of cosmic rays

Time for the Fantastic Four to appear? Finally!

"In 2009, cosmic ray intensities have increased 19% beyond anything we've seen in the past 50 years," says Richard Mewaldt of Caltech. "The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions."

The sun's magnetic field is our first line of defense against these highly-charged, energetic particles. The entire solar system from Mercury to Pluto and beyond is surrounded by a bubble of magnetism called "the heliosphere." It springs from the sun's inner magnetic dynamo and is inflated to gargantuan proportions by the solar wind. When a cosmic ray tries to enter the solar system, it must fight through the heliosphere's outer layers; and if it makes it inside, there is a thicket of magnetic fields waiting to scatter and deflect the intruder.

Earth is in no great peril (remember this when your body will take fire – flame on!). Our planet's atmosphere and magnetic field provide some defense against the extra cosmic rays. Indeed, we've experienced much worse in the past. Hundreds of years ago, cosmic ray fluxes were at least 200% to 300% higher than anything measured during the Space Age. Researchers know this because when cosmic rays hit the atmosphere, they produce an isotope of beryllium, ¹⁰Be, which is preserved in polar ice. By examining ice cores, it is possible to estimate cosmic ray fluxes more than a thousand years into the past. Even with the recent surge, cosmic rays today are much weaker than they have been at times in the past millennium.