ESA’s Cluster mission establishes why Earth’s aurorae shine


Aurorae over Canada
 
Auroral displays over Canada pictured from the International Space Station from an altitude of 400 kilometres. The Manicouagan impact crater is visible in the foreground.

Thanks to observations performed in 2001 and 2002, ESA’s Cluster mission has established that high-speed flows of electrified gas, known as bursty bulk flows, in the Earth’s magnetic field are the carriers of decisive amounts of mass, energy and magnetic perturbation towards the Earth during magnetic substorms. When substorms occur, energetic particles strike our atmosphere, causing auroras to shine.


 
This ultraviolet image shows an auroral display as seen from space, overlaid on top of a visible image of Earth. The false-color reds indicate the brightest aurora and blue the dimmest. The brightest aurora is found at midnight.

Magnetic substorms over northern Asia
 
This sequence of images, captured by the Ultraviolet Imager on NASA's Earth-orbiting POLAR satellite, shows a magnetospheric substorm over northern Asia as imaged on 24 February 2000. The maximum activity, indicated by dynamic yellow blobs in the aurora's oval, occurs around 14:00 UT (15:00 CET).



Release date: 30 August 2010