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Article 2006

From Knowxnews, April 10, 2006

Sky Guy: Preparing for the first-ever stereoscopic study of solar outbursts

By Thomas R. Webber, Sky Guy
April 10, 2006

Of all of the galaxy's celestial citizens, the Sun is the most vital to the development and continuation of life on our planet. Yet despite its importance to Earth, we find that the Sun is just another star in the Milky Way, neither special nor distinctive in its position, composition, size or age.

But to scientists, the Sun is a vivid and spectacular theater where we can study and witness firsthand the violent nature of stars and the interaction of matter and energy. With the next-closest star being more than 4 light-years from Earth, it would seem that we do have front-row seats to this nuclear powerhouse.

NASA is taking a next step in understanding the nature of the Sun this month. On Tuesday, STEREO (Solar Terrestrial Relations Observatory) will launch from Cape Canaveral, Fla., the third mission in NASA's Solar Terrestrial Probes program.

The two-year STEREO mission is unique in that it will utilize two nearly identical space-based observatories. About the size of a car, each weighs about 1,300 pounds and utilizes (appropriately enough) solar power.

What is interesting is the placement of these probes. One will be ahead of Earth in its orbit, and the other will be trailing behind.

This configuration will allow the first-ever stereoscopic study of the Sun and phenomena called Coronal Mass Ejections, or CMEs.

The corona is the outer layer of the Sun's atmosphere and extends several million miles into space, gradually becoming the solar wind (heat, light, and electrons that flow through the solar system).

CMEs are incredibly powerful eruptions that can blow as much as 10 billion tons of the Sun's atmosphere into interplanetary space at speeds of up to 1 million miles per hour.

The STEREO observatories will utilize four instrument packages to learn more about the cause, mechanism and propagation of CMEs, including how they evolve as they travel through the interplanetary medium. The probes will also examine the solar wind.

So why all the hubbub over CMEs? These energetic bursts can cause tremendous disturbances in the solar system, including the creation of severe magnetic storms when they collide with Earth's magnetic field. These geomagnetic storms can damage or destroy orbiting satellites and can cause electrical instabilities and even power outages on Earth's surface.

In addition, CMEs can be hazardous to astronauts during extra-vehicular activities (EVAs) when the shielding of the space shuttle does not protect them.

By learning more about CMEs and our own star, we can begin to anticipate and possibly even develop new technologies to protect our machines, our planet and our people from these temperamental outbursts from our Sun.

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