As it happens, you have the opportunity to step out your door in the coming weeks, and observe a comet described by NASA as "glowing alien green" yourself. Here's how to see Comet Machholz in early January:
With a diameter of at least 450,000 kilometers, the coma of this comet is at least three times wider than the planet Jupiter. Named after its discoverer, amateur Don Machholz, astronomers have been watching it since last August. This week is its closest approach - about 52 million kilometers. The cometary body itself is small; its two tails (the ion tail points up; the dust tail points down in the picture below) are what give it size. The comet glows green because its coma contains cyanogen and diatomic carbon, both of which glow green when illuminated by sunlight.
And the peculiar ellipsoid shape seen in the novel? Twelve million miles long, it was a ship; its green surface was an impenetrable force barrier. Its masters were beings of light and mist. You'll need to read the novel to see what it contained, but here's a hint; the paths of the bodies in our solar system are ellipsoidal.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)