Experts say that the comet will be at a distance of 42 million kilometers from the Earth, which is a very small distance for the green comet. What makes the celestial event unique is that the next comet that will be visible to humans will be after another 50,000 years. 🔬 Green Comet To Come Closest to Earth on February 1, Will Be Visible to Naked Eye; Know When, Where and How To Watch the Rare Celestial Event.