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Space Weather and You

The sun is a dynamic system, and its dynamics can and do affect us here on earth. Let’s look at some of the effects due to solar activity:

Satellites and Spacecraft
Satellites and spacecraft are affected by solar activity both directly and indirectly. High-energy particles from the sun can have direct impact by destroying sensitive microchips. Incoming charged particles can create buildups of charge inside electronics, resulting in destructive arcing and false signals. Also, particle bombardment can degrade the solar panels that supply electric power—a potentially fatal development if that power is being used for life support systems on spacecraft.

Indirectly, space weather can affect satellites by heating the upper atmosphere and causing it to expand. The expanded atmosphere is denser at higher altitudes, and this greater density puts a drag on orbiting satellites. Slowed by this drag, satellite orbits decay and ultimately require “boosting,” lest they burn up in the earth’s dense lower atmosphere.

Radio Communication
Shortwave radio communication (used mainly by the military and for long-range broadcasts) works by bouncing radio signals off a charged layer of particles in our atmosphere called the ionosphere. Geomagnetic storms disturb the ionosphere, making radio communication spotty and sometimes impossible.

Most navigation systems rely on GPS, the Global Positioning System, which in turn relies on carefully timed and triangulated signals from satellites. Geomagnetic storms cause sudden variations in the density of the ionosphere. As a result, GPS signals from satellites arrive at GPS receivers slightly early or late, leading to inaccuracies.

Meanwhile, geomagnetic storms may affect animal navigation too. Many migratory animals have internal biological compasses, thanks to tiny grains of a magnetic mineral (magnetite) in their brains. Geomagnetic storms may disorient these animals, causing whales to beach and carrier pigeons to lose their way.

Electric Power Transmission
Geomagnetic storms induce electric currents in the cables and transformers of electric power systems. These induced currents can damage equipment, leading to power failures. A geomagnetic storm on March 13, 1989, caused a major blackout in Quebec, leaving six million people without power. With warning from space weather forecasters, power companies can take steps to minimize failures.

Geomagnetic storms can also induce electric currents in pipelines, such as those used to transport oil. Electric current flow in these pipelines causes them to corrode rapidly, leading to expensive repairs.

Astronauts and High-Altitude Travelers
Radiation and high-energy particles from the sun can damage living tissue. Here on the ground, we are protected by the combined action of the magnetosphere and the atmosphere. However, astronauts are subject to potentially lethal doses of radiation.

In addition to space travel, high-altitude flights on polar routes during geomagnetic storms can expose crew and passengers to increased radiation. Airlines monitor space weather forecasts and sometimes make changes to flight paths during solar storms to lessen this exposure.

It is already known that changes in the energy output of the sun can affect the climate here on earth. For example, the sun undergoes an 11-year cycle of activity, also known as the solar cycle. During solar maximum, the peak of the 11-year cycle, the sun shines a tiny bit brighter (up to one half of a percent). Studies of tree-ring thickness show that plant growth follows the ups and downs of the solar cycle. Another example is a historical event called the Maunder Minimum, a 65-year dip in solar activity that caused a period of global cooling on earth in the late seventeenth century. During this time, known as the Little Ice Age, temperatures plunged and the Baltic Sea froze over regularly.

Scientists are speculating that galactic cosmic rays (high-energy particles from outside our solar system) may also affect the earth’s climate. Some think that cosmic rays are involved with cloud formation in our atmosphere because they create ions (charged particles) in our atmosphere; ions act as “seeds” (or nucleation centers) for clouds.

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