These ions emit radiation at various wavelengths, creating the characteristic colours (red or greenish blue) of the aurora.The Norwegian singer-songwriter AURORA recently released her sixth studio album The Gods We Can Touch, and it’s everything you’d expect from the art pop phenomenon. They collide with oxygen and nitrogen atoms, knocking away electrons from these atoms to leave ions in excited states. Alfvén waves-which are generated in the dayside and nightside regions of the magnetosphere and in the region of the magnetosphere called the magnetotail-push these electrons along and accelerate them up to 72.4 million km (45 million miles) per hour. Some electrons are captured by Earth’s magnetic field ( see geomagnetic field) and conducted along magnetic field lines downward toward the magnetic poles. Electrons and other charged particles, which are released by coronal mass ejections, solar flares, and other emanations from the Sun, are driven outward by the solar wind. The display ends with a poleward retreat of the auroral forms, the rays gradually degenerating into diffuse areas of white light.Īuroras receive their energy from charged particles traveling between the Sun and Earth along bundled ropelike magnetic fields. Greenish rays may cover most of the sky poleward of the magnetic zenith, ending in an arc that is usually folded and sometimes edged with a lower red border that may ripple like drapery. The lower edges of the arcs and folds are usually much more sharply defined than the upper parts. However, in a great display, other forms appear, commonly undergoing dramatic variation. The uniform arc is the most stable form of aurora, sometimes persisting for hours without noticeable variation. Watch the aurora australis, the southern lights, from outer space See all videos for this articleĪuroras take many forms, including luminous curtains, arcs, bands, and patches. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.
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