... Air Pollution Earth . 9.07.2001 . Where on Earth is the air most polluted? ... The Galactic Center in Infrared . ... In visible light, much of the Galactic Center is obscured by opaque dust. ... C 2001 A2 (LINEAR): Comet . ... Outward bound, this primordial piece of the solar system is still just visible to the unaided eye and can now be sighted by northern hemisphere skygazers as it moves through the constellation Pisces. ... Just as rainbows are lit by the Sun, moonbows are lit by the Moon. ...