When the UV rays of solar radiation fall on the comet, these molecules emit green light. The comet was visible last month as well. However, the glow was not much due to the large distance from our home planet. Astronomers captured pictures which showed the head of the comet's body its long, more teenage iron and adjust tail. However, as it is set to approach the Earth, the comet will be glowing more and can be seen from the naked eye