Auroras Revealed

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Auroras Revealed
03.05.08
 
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Introduction

Blooming flowers, chirping birds and warmer weather are all signs that spring has arrived. But a lesser-known sign of spring are auroras, or the Northern Lights. For reasons not yet fully understood by scientists, the weeks around the vernal equinox are prone to auroras. But NASA is aiming to solve this mystery and others with a new mission to study the Northern Lights, called THEMIS.



Transcript

Narrator: With spring right around the corner it’s the season for auroras.

Also known as the northern lights, auroras are the brilliant curtains of colored light that appear in the night sky in the far northern or southern regions of the world.

Although auroras are spectacular to watch, they’re actually a manifestation of violent space weather.

Nicky Fox, NASA scientist: These are just caused by energy coming into our Earth's magnetic atmosphere causing the whole magnetic field to reconfigure and end up with an explosive release of high-energy electrons and protons into our earth's atmosphere, where they strike the molecules, both oxygen and nitrogen and cause them to glow.

Narrator: Besides igniting the northern lights, these substorms can create big problems here on Earth by disrupting power grids, satellites, air travel and even GPS signals.

Spring is one of the best times to view the auroras because the substorms that spark them are more frequent in the months around the equinoxes. Plus the longer nights provide a great backdrop for these stunning displays.

While auroras have fascinated observers for centuries, little had been known about their origin. But NASA’s aiming to resolve this mystery with a new mission to study the northern lights, called THEMIS.

The THEMIS mission uses 5 identical satellites, and a network of ground observatories to track and determine what triggers the auroras that occur during substorms.

And since its launch just last year, THEMIS has made some important discoveries.

David Sibeck, NASA scientist: Even in the first days of our mission we've used these five spacecraft and the dedicated array of ground observatories to track aurora racing westward across canada and alaska and time their motion and understand where they occur.

As our knowledge about the northern lights continues to expand, pretty soon auroras may not seem so mysterious after all.

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