A green comet, you say? If you're a science fiction fan, I know what you're thinking - what about Cometeers?
"Perhaps it's a comet." Still frowning, Bob Star swung back toward the observatory. "It looked like one - it was a short streak of that queer, misty green, instead of the point a star would show..."
Inside the chilly gloom of the observatory, Bob sat down at the telescope. Its mechanisms whirred softly, in swift response to his touch. The great barrel swung to search space with its photoelectric eyes, and the pale beam of the projector flashed across to the concave screen.
...He stepped up the electronic magnification. Vindemiatrix and the fainter stars slipped out of the field. The comet hung alone, and swiftly grew. Its shape was puzzling - a strangely perfect ellipsoid. A greenish football, he thought, kicked at the System out of the night of space - by what?
It turns out that they are seeing an alien force field millions of miles in extent, containing worlds enslaved by the Cometeers, an alien race of energy beings.
Sure, you're skeptical - it's just science fiction. Sometimes a green comet - is just a green comet; cyanogen and diatomic carbon in the coma cause the green color. But what if I told you this green comet is sneaking up from below the solar system?
Comet Lovejoy's orbit is almost perpendicular to the plane of the ecliptic. At present (20-Mar-2007), the comet is approaching the solar system from below, moving from southern to northern skies. Comet Lovejoy is expected to brighten to 7th magnitude (not quite a naked-eye object), at the point in its orbit when it is closest to Earth (.44 AU - about 41 million miles).
This sounds underhanded to me; it's just the sort of thing you'd expect from the Cometeers. Fortunately, the Aussies (and Kiwis) are obviously alert.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)