Radiation From Solar Activity
Solar flares, coronal mass ejections (CMEs) and geomagnetic storms from the sun can send extreme bursts of
ionizing radiation and magnetic energy toward Earth.

About Radiation From Solar Activity

Solar flares, CMEs and geomagnetic storms are examples of extreme sun activity that can send bursts of
energy toward Earth. Some of this energy is in the form ionizing radiation and some of the energy is magnetic
energy.

SUNSPOTS
Sunspots are areas of very strong magnetic fields on the surface of the sun. These magnetic fields can
become twisted, storing energy like a  rubber band. Scientists don't fully understand why, but sunspots can
become unstable and explode, releasing  huge amounts of energy into space. According to the U.S. National
Air and Space Administration (NASA), the energy released is "the equivalent of millions of 100-megaton
hydrogen bombs exploding at the same time!" This is called a solar flare.

SOLAR FLARES
Solar flares contain different forms of energy: heat, magnetic energy and ionizing radiation. The ionizing
radiation released during  solar flares includes x-rays and gamma rays. The ionizing radiation from these bursts
can damage satellites, which travel above the protection of Earth's atmosphere.  Damage to communications
                                 satellites could disrupt communications on Earth. The magnetic energy
                                 from solar flares could also interrupt radio communication on Earth.
                                 While solar flares are massive explosions,  you still need specialized
                                 equipment to see them on the surface of the sun.

                                 CORONAL MASS EJECTIONS (CMEs)
                                 The most powerful solar flares are huge bursts of x-rays and electrified
                                 hot gas called coronal mass ejections, which can create proton storms.
                                  Protons are the positively charged particles from the nucleus of an atom.
                                 The explosion that creates the CME accelerates the protons around the
                                 sun to nearly the speed of light. These  protons are a form of ionizing
                                 radiation. Protons carry dangerous amounts of energy that can break
                                 chemical bonds.

                                  Proton storms can interfere with ham radio communication and damage
                                 satellites, causing short circuits in electrical systems and shutting down
                                 computers. An astronaut outside the International Space Station (ISS)
                                 during a proton storm would become sick due to the ionizing  radiation
                                 exposure. The light and x-rays from CMEs reach Earth's atmosphere in
                                 about 8 minutes. Usually, the atmosphere protects people on the surface
                                 from the proton storm.
Coronal mass ejection, as
observed by the Solar and
Heliospheric Observatory
      spacecraft.
   United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608T) |  EPA 402-F-14-010 |August2014| p. 1

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                                                                 Aurora borealis or northern lights.
The charged particles from a proton storm interact with the
atmosphere and cause spectacular changes to the atmosphere
known as the aurora borealis or northern lights.
In 1859, a proton storm from CMEs was so powerful that people in
Cuba and  Hawaii saw the northern lights. The increase in charged
particles caused such strong electrical currents in telegraph wires that
some offices caught fire. Because such a powerful proton storms
could cause a lot of damage to technology that we rely on today,
NASA tracks the sun's activity so we can prepare for large proton
storms.

Rules and Guidance

U.S.  FEDERAL AVIATION ADMINISTRATION (FAA)

Solar activity can cause commercial airlines' navigational equipment to report the location of planes incorrectly.
Fortunately, there are systems available to pilots that are not sensitive to solar activity. If navigators are alerted
to the storm, they can switch to a backup system. The FAA routinely receives alerts of solar flares. These
alerts allow them to be prepared for potential communication and navigation problems.

U.S.  NATIONAL AERONAUTIC AND SPACE ADMINISTRATION (NASA)
NASA's Solar Particle Alert Network (SPAN) consists of multiple radio and optical telescopes that stream
continuous data on solar flare activity. Solar flare eruptions are difficult to predict. However, the instruments
used by SPAN can provide some warning. They can detect solar material as it makes its way from the sun to
Earth. This information also allows astronauts in space, who lack the protection of Earth's atmosphere, to
move to well shielded areas of their spacecraft.

U.S.  NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA)
NOAA's Space Environment Center provides real-time monitoring and forecasting of solar and geophysical
events. They also develop techniques for forecasting solar and geophysical disturbances.

What you can do

Radiation from solar activity is a natural part of our environment and does not threaten our health on a day-to-
day basis. UV rays from the sun pose a much more common, ongoing risk to human health. You should take
steps such as wearing sunscreen and protective clothing to protect yourself from UV radiation.

Where to learn more

You can learn more about radiation from solar activity by visiting the resources available on the following
webpage:  http://www.epa.qov/radtown/solar-activity.htmltfresources.
United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608T) | EPA 402-F-14-010 | August2014 |  p. 2

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