Space
How Pulsating, Colorful Auroras are Created with Tiny Particles in Earth's Atmosphere
Catherine Griffin
First Posted: Oct 12, 2015 03:25 PM EDT
The aurora can be one of the most beautiful natural light displays on Earth with wavering lines of blue, green, purple and pink. Now, scientists have learned a bit more about this phenomenon due to a very lucky conjunction of two satellites and a ground-based array of all-sky cameras during an aurora borealis.
In this case, the researchers looked at pulsating auroras. These natural lights are so-named because their features shift and brighten in distinct patches, rather than elongated arcs across the sky like active auroras. However, their appearance isn't the only difference. While all auroras are caused by energetic particles speeding down into Earth's atmosphere and colliding with the atoms and molecules in the air, the source of these electrons is different for pulsating auroras and active auroras.
Active auroras occur when a dense wave of solar material-such as a high-speed stream of solar wind or a large cloud that exploded off the sun called a coronal mass ejection-hits Earth's magnetic field, causing it to rattle. This rattling releases electrons that have been trapped in the tail of that magnetic field, which stretches out away from the sun. Once released, these electrons head toward the poles, and then interact with the particles in Earth's upper atmosphere to create the aurora.
In contrast, the electrons that set off pulsating auroras are sent spinning to the surface by complicated wave motions in the magnetosphere. These wave motions can happen at any time and not just when a wave of solar material rattles the magnetic field.
In this latest study, the researchers found that the most distinct change in the structure and shape of the aurora happened during times when far fewer of these secondary electrons were shooting in along hemispheric magnetic field lines. In fact, it's likely that secondary electrons could very well be a big piece of the puzzle to how, why, and when the energy creating auroras is transferred to the upper atmosphere.
The findings are published in the Journal of Geophysical Research: Space Physics.
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First Posted: Oct 12, 2015 03:25 PM EDT
The aurora can be one of the most beautiful natural light displays on Earth with wavering lines of blue, green, purple and pink. Now, scientists have learned a bit more about this phenomenon due to a very lucky conjunction of two satellites and a ground-based array of all-sky cameras during an aurora borealis.
In this case, the researchers looked at pulsating auroras. These natural lights are so-named because their features shift and brighten in distinct patches, rather than elongated arcs across the sky like active auroras. However, their appearance isn't the only difference. While all auroras are caused by energetic particles speeding down into Earth's atmosphere and colliding with the atoms and molecules in the air, the source of these electrons is different for pulsating auroras and active auroras.
Active auroras occur when a dense wave of solar material-such as a high-speed stream of solar wind or a large cloud that exploded off the sun called a coronal mass ejection-hits Earth's magnetic field, causing it to rattle. This rattling releases electrons that have been trapped in the tail of that magnetic field, which stretches out away from the sun. Once released, these electrons head toward the poles, and then interact with the particles in Earth's upper atmosphere to create the aurora.
In contrast, the electrons that set off pulsating auroras are sent spinning to the surface by complicated wave motions in the magnetosphere. These wave motions can happen at any time and not just when a wave of solar material rattles the magnetic field.
In this latest study, the researchers found that the most distinct change in the structure and shape of the aurora happened during times when far fewer of these secondary electrons were shooting in along hemispheric magnetic field lines. In fact, it's likely that secondary electrons could very well be a big piece of the puzzle to how, why, and when the energy creating auroras is transferred to the upper atmosphere.
The findings are published in the Journal of Geophysical Research: Space Physics.
Related Stories
ISS Astronaut Captures Spectacular Aurora Footage During a Sunrise (VIDEO)
'Northern Lights' Aurora Spotted on Distant Brown Dwarf Outside Our Solar System
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone