... Note: Click here a longer, much more comprehensive overview of the polar aurora . ... Magnetic Field . ... Aurora . ... 3b. Fritz Aurora . ... Electrons . ... Typical aurora (Dick Hutchinson ї) . In Alaska, Canada, Norway, Finland or northern Russia, on a clear night, a greenish glow is often seen in the sky, known as the "Northern Lights." ... Auroral light is produced at a height of about 100 km (60 miles) when fast electrons, arriving from space, slam into atoms and molecules of the atmosphere. ...
... Views of Martian Clouds . ... Although not as pronounced as on Earth , clouds are common features on Mars. The Martian atmosphere has only a trace of water vapor; however, the temperature and pressure is such that the atmosphere is usually close to saturation and produces clouds. Even from Earth based telescopes, clouds have been observed by transient brightening on the surface of Mars. ... Lee waves . ... Wave clouds . ... Image Credit: Calvin J. Hamilton) . Lee Wave . ... Wave Clouds . ...
... In the 1800s it was already evident that the Earth's magnetic field was involved: auroral rays seemed to follow the Earth's magnetic field lines, and the frequency with which aurora was observed depended on the distance from the magnetic pole, not from the geographic one. ... That is the beginning of the ionosphere , a layer with enough free electrons (and ions) to play an important role in radio communications. ... The simplest atom is the one of hydrogen, with just one electron. ...