A pair of once-in-a-lifetime comets will rocket through our skies this October. It's a rare treat for skywatchers, as they won't be back again for hundreds of years. The comets -- C/2025 A6 (Lemmon) and C/2025 R2 (SWAN) -- look similar from our perspective. You can spot these green gaseous globes and their streaming tails…

Photo By CNET

Photo By CNET