1A natural electrical phenomenon characterized by the appearance of streamers of reddish or greenish light in the sky, especially near the northern or southern magnetic pole. The effect is caused by the interaction of charged particles from the sun with atoms in the upper atmosphere. In northern and southern regions it is respectively called aurora borealis or Northern Lights and aurora australis or Southern Lights.
- ‘The Hubble Space Telescope has spotted auroras near the poles of both Saturn and Jupiter.’
- ‘Gaps in the magnetosphere also allow for one of Earth's most beautiful, eerie phenomena: the aurora borealis, or northern lights.’
- ‘Bound to the Earth, our only naturally occurring experience with space weather comes from what we can see with our eyes: eclipses, comets, auroras, and sunspots.’
- ‘This causes the phenomenon called the northern lights, also known as the aurora borealis.’
- ‘Although the solar wind produces beautiful auroras, it can also cause a variety of undesirable consequences.’
- ‘He expanded on their work by pulling in historical records of auroras, naked-eye sunspots, and eclipses.’
- ‘The eventual physical effects of the storm were minimal - auroras were visible in Boston and other northern U.S. cities, but no satellites or power grids had major failures.’
- ‘Experts used to think it was just a matter of the air being heated by particles and electric currents in the regions around the poles, where auroras occur.’
- ‘Colorful sky lights called auroras may be active at high latitudes and possibly into northern U.S. states and Europe.’
- ‘Birkeland's experiments failed to account for one of the most important traits of auroras: they are common around the polar regions but exceedingly rare at the poles themselves.’
- ‘A typical example of how both missions will co-operate is the study of the magnetic substorms producing the bright aurorae.’
- ‘In the southern hemisphere, sky watchers saw the aurora australis over New Zealand, Australia, and South Africa.’
- ‘And then last week another big storm that caused auroras and beautiful geo magnetic activity all over the world.’
- ‘As it is, auroras on Earth follow magnetic lines of force that converge at the north and south magnetic poles.’
2literary The dawn.daybreak, break of day, crack of dawn, sunrise, first light, daylight, first thing in the morning, early morning, cockcrow
proper nounRoman Mythology
Goddess of the dawn.
1A city in north central Colorado, east of Denver; population 319,057 (est. 2008).
2An industrial city in northeastern Illinois; population 171,782 (est. 2008).