aurora

noun au·ro·ra \ ə-ˈrȯr-ə , ȯ- \

|Updated on: 14 Aug 2018

Definition of aurora

plural auroras or aurorae play \-(ˌ)ē\

1 : dawn

2 capitalized : the Roman goddess of dawn — compare eos

3 : a luminous phenomenon that consists of streamers or arches of light appearing in the upper atmosphere of a planet's magnetic polar regions and is caused by the emission of light from atoms excited by electrons accelerated along the planet's magnetic field lines

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auroral

play \-əl\ adjective

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aurorean

play \-ē-ən\ adjective

See aurora defined for kids

Examples of aurora in a Sentence

a gorgeous pink aurora aroused us out of our slumber

Recent Examples of aurora from the Web

To get an idea of what’s in store, these bright bands of green auroras were captured just after midnight on Tuesday over Lake Superior near Copper Harbor, Michigan.

— lyndsey matthews, Country Living, "There's Another Chance to See the Northern Lights Tonight," 11 Apr. 2018
This stream of particles can mingle with Earth’s magnetic field, causing geomagnetic storms that mess with our satellites and power grid and create auroras.

— loren grush, The Verge, "The NASA spacecraft that will journey to the Sun just got its super deluxe heat shield," 8 July 2018
Elders tell their stories and a narrator tells us of the sun's essential role in creating the aurora.

— ned rozell, Anchorage Daily News, "Where myth meets science: The northern lights in Nuiqsut, seen inside a portable planetarium," 21 Apr. 2018
An aurora’s colors depend on what kind of atom cosmic particles smash into.

— robert ormerod, National Geographic, "Why Space Fans Flock to This Eerie Landscape," 9 Apr. 2018
Bright, colorful aurora, visible to the naked eye, lit up the night sky in both hemispheres.

— angela fritz, Washington Post, "A solar shock wave cracked Earth’s magnetic field last night, but everything is fine," 20 Apr. 2018
As well as studying the aurora and magnetosphere, Juno also helps scientists probe the gravitational field of Jupiter’s interior in exquisite detail by monitoring small tweaks to the spacecraft’s orbit—down to 1,900 miles below the clouds.

— andrew coates, Newsweek, "NASA Juno Unlocks Secrets of Jupiter's Mega Cyclone Clusters," 8 Mar. 2018
National Geographic reports that aurora chasers and citizen scientist photographers began to spot a purple plasma ribbon in the night sky a few years ago.

— gabriella paiella, The Cut, "Rare and Majestic Natural Phenomenon Named … Steve," 16 Mar. 2018
Amateur aurora watchers have taken hundreds of photographs of this adjacent phenomenon, often drawing out its fluorescent colors with long exposures or photo editing.

— jacey fortin, New York Times, "Steve, a Famous Northern Light, Stays Mysterious (and Keeps His Name)," 15 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'aurora.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.