... The beautiful Trifid Nebula (aka M20), a photogenic study in cosmic contrasts, lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. ... What size particles compose Saturn's rings? To help find out, the robot Cassini spacecraft now orbiting Saturn broadcast radio waves of three different wavelengths right through the rings to Earth earlier this month. ... Observations of rings bordering the Keeler gap in Saturn's rings showed unusual waves. ...