This brief history description of Aurora Australis and it's characteristics are revealed on the site:
The Aurora Australis is a natural phenomena of the southern hemisphere in which the sky is filled with mysterious lights due to magnetic forces in the atmosphere. Plasma particles from the sun enter the atmosphere and collide with the Earth's magnetic field, causing light to be released (similar to electrons passing through gases in a neon tube). Particularly intense auroral storms can produce up to one trillion watts of electricity.
The Aurora Australis occurs in an oval around the South magnetic pole. Auroras typically last for 15–40 minutes and may recur in 2 to 3 hours. The most common colours are green and pink, but they can also be red, yellow, violet and blue.
Sam e-mails Tracey inquiring about the strange phenomenon that he had seen the previous night while walking the deck of the Christiane I, and requests and explanation as to what it may have been. Tracey replies by saying that the phenomenon usually occur near the polar regions, but have been known to occur elsewhere as well, but they don't usually fade away that quickly. Tracey states that she doesn't think it's anything sinister, just a little weird.
OK, try and explain this one Miss Rational Explanation for Everything.
The other night I was on the deck when I saw what looked like a cloud of green light on the horizon. I grabbed my binoculars for a closer look -- it was a series of long green streaks that moved slowly and blended with each other. After about 20 seconds or so they faded away.
Hmmm, strange green lights in the sky? Let's see, in my thoughtful and considered opinion I'd say it's most definitely an invasion of little green aliens from the planet Zubelleedubellee. Ruthless creatures. They eat people brains... have you checked yours lately? ;)
Seriously, there's a perfectly rational explanation for what you saw. It was more than likely an aurora. It's a natural phenomenon caused by magnetic forces in the atmosphere. They usually only happen around the polar regions but have been know [sic] to occur elsewhere. Mind you they don't normally fade away quickly like yours did. Could be related to the mishap on the bridge the other day but it's hard to tell for sure. I'm sure it's nothing sinister (just a little weird).