![]() ![]() In vivid reds, greens, yellows, and blues, auroras look like wavy or shimmering curtains that can stretch across the horizon. They are generally not visible during daylight hours, although on clearer nights, auroras have been viewed within an hour before and after sunrise. Auroral lights are usually only viewable near local midnight. Cloudy or overcast skies decrease visibility, but scientists don’t fully understand the reason that auroras are more frequently observed during these months. In North America, auroras are most commonly visible in March and November when cloud cover diminishes somewhat. Many locations in Alaska, for instance, are front-row seats for these amazing light displays. NCEI’s World Magnetic Model can be used to calculate the location of the magnetic poles. Views from near Earth's magnetic poles, where the magnetic field converges, are more optimal than from the geographic poles. Earth's magnetic poles are offset from the geographic poles. The closer a skywatcher is to the higher latitudes, the more likely auroras will be visible. The chances of glimpsing these spectacular “dancing” lights improve during certain times of the year and under certain conditions. From this interaction, auroral light is emitted. There, they collide with oxygen and nitrogen atoms in Earth’s upper atmosphere. Magnetospheric electrons can be accelerated by various processes and are lost to the atmosphere as they flow along magnetic field lines in the polar regions towards the Earth. ![]() Courtesy of Wikimedia Commons.Įarth’s magnetic field lines converge at the geomagnetic north and south poles, which are offset from the geographic poles. The shape and size of Earth’s magnetic field continually change as the field is buffeted by solar wind. ![]() The force of the wind as it impacts and flows around the magnetosphere affects the shape of the magnetosphere. Electrically conductive plasmas in the solar wind and the magnetosphere are not free to cross one another, so when solar winds hit the magnetosphere they don’t flow through our magnetic bubble but must go around. The magnetosphere is the region of space surrounding Earth where the dominant magnetic field is the magnetic field of Earth, rather than the magnetic field of interplanetary space. When these powerful surges arrive at Earth, they reshape our magnetosphere. These eruptions carry as much energy as a modern nuclear reactor could produce if it ran continuously for hundreds of thousands of years. Solar matter can be flung past our position 93 million miles from the sun and can reach the remotest edges of our solar system. Space Weather and MagnetismĪlthough aurora lights appear most frequently near the poles-the aurora borealis to the north and the aurora australis to the south-space weather happens on a much larger scale. NOAA scientists monitor and track these geomagnetic storms and other phenomena related to space weather. Auroras can also be triggered by much less energetic events that lead to active conditions, such as fast solar wind streams from coronal holes. Space weather-caused by solar activity such as solar flares and coronal mass ejections-can impact the space between here and the sun and cause an aurora as a byproduct. Rather than the calm before the storm, aurora is the light show after the storm in space.Īuroras above the Northern and Southern Hemispheres evolve from the sun’s activity that affects the conditions in space on an enormous scale. The mystery behind these shimmering curtains of neon-like light isn’t a mystery to scientists who study space weather. A geomagnetic storm lies behind every inspiring aurora in our skies.
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