Image: Green Comet Makes Its Debut
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Top Ten Space Pictures of 2009: Green Comet Makes Its Debut
Comet Lulin is framed by red-lit trees in Virginia's Shenandoah National Park in a picture taken February 23. The green, "two tailed" comet made its closest approach to Earth in February, swinging past at about 38 million miles (61 million kilometers). And considering the comet's nearly parabolic orbit, experts said, that first visit may have been its last.
Because of its angle of approach, Lulin appeared to have a second anti-tail pointing toward the sun as it neared Earth. Vaporizing ices from the comet included cyanogen and diatomic carbon, both gases that glow green in sunlight out in the vacuum of space.
— Photograph by Bill Ingalls/NASA via AP