damage satellites and even ground-based technologies and power grids. Every 11 years, as the sun

reaches it's maximum activity they become bigger and more common, and that increases

the chances that one will significantly affect Earth. So what are these solar eruptions?

A solar flare is basically an explosion on the surface of the sun ranging from minutes

to hours in length. Large flares can release enough energy to power the entire United States

for a million years. Flares happen when the powerful magnetic fields in and around the

sun reconnect. They're usually associated with active regions, often seen as sun spots,

where the magnetic fields are strongest. Flares are classified according to their strength.

The smallest ones are B-class, followed by C, M and X, the largest. Similar to the Richter

scale for earthquakes, each letter represents a ten-fold increase in energy output. So an

X is 10 times an M and 100 times a C. Within each letter class, there is a finer scale

from 1 to 9. C-class flares are too weak to noticeably affect Earth. M-class flares can

cause brief radio blackouts at the poles and minor radiation storms that might endanger

astronauts. It's the X-class flares that are the real juggernauts. Although X is the last

letter, there are flares more than 10 times the power of an X1, so X-class flares can

go higher than 9. The most powerful flare on record was in 2003, during the last solar

maximum. It was so powerful that it overloaded the sensors measuring it. They cut-out at

X17, and the flare was later estimated to be about X45. A powerful X-class flare like

that can create long lasting radiation storms, which can harm satellites, and even give airline

passengers flying near the poles small radiation doses. X flares also have the potential to

create global transmission problems and world-wide blackouts. The seriousness of an X-class flare

pointed at Earth is why NASA and NOAA constantly monitor the sun. NASA's Heliophysics fleet

of spacecraft can now see the sun from every side and in many different wavelengths. This

unprecedented coverage is enabling scientists to predict and detect space weather events

like flares and CMEs with ever greater accuracy. With advance warning, governments and companies

can take steps to protect their technological infrastructure, so that the worst scenarios

will never happen. Beeping Beeping