Watching great comets shine brightly in the sky for 18 months
Hale-Bopp comet is 1,000 times brighter than Halley's comet at the time of discovery. The pale blue tailed white tail can even be observed in urban-polluted cities like Chicago.Comet 'encounter' Earth
According to astronomers, comet Hartley 2 and Earth will have a close encounter this month.