This image is of Atlantis and its Orbital Boom Sensor System robot arm extension backdropped against Earth’s horizon and a greenish phenomenon associated with Aurora Australis. One of the station’s solar array panels appears at upper left. Because of the exposure time needed for this type of photography, some of the stars in the background are blurred.
Taken recently by the crew of the NASA STS-135 Atlantis, the aurora is one of the things I really want to see in person – hopefully in Alaska – as I don’t particularly think there is much else to do in Antarctica.
The phenomena is awesome. The Earths magnetosphere protects us from the solar wind (ionized gas) generated by our closest star, the Sun. These winds usually reaches Earth with a velocity around 400 km/s, but as a result of sunspots, this is sometimes several times faster.
The ionized gas from solar wind captured and accelerated along the magnetic field lines of the Earth towards either the North or the South Magnetic Poles, as they are accelerated, they interact with the Earths’ Atmosphere, causing oxygen and nitrogen particles to be “excited”. This electron excitement causes light-waves to be emitted, and depending on if they are gaining or losing electrons, emit yellow, red, blue, pink or green light.
Interestingly enough, on 2 September 1859 a strong geomagnetic storm was able to provide free electricity… for some telephone operators. It is also notable for the fact that it is the first time where the phenomena of auroral activity and electricity were unambiguously linked.
While a significant portion of the 201,000 km of telegraph lines then in service was significantly disrupted throughout the storm, some telegraph lines however seem to have been of the appropriate length and orientation to produce a sufficient geomagnetically induced current from the Electromagnetic field to allow for continued communication with the telegraph operators’ power supplies switched off.
The aurora was thought to have been produced by one of the most intense coronal mass ejections in history, very near the maximum intensity that the Sun is thought to be capable of producing.