People may think you are being odd but by waving to the sky this afternoon you will be helping out NASA. The folks at NASA are encouraging everyone to take a minute to say hello to Saturn today.  Scientist Linda Spilker explains that the Cassini spacecraft will be taking pictures of Earth from the Saturn system, and they want as many people as possible to get outside and wave at the ringed planet.  The celestial photo shoot is scheduled to start at 2:27 p.m. PT, and will last for about 15 minutes.  Spilker says this isn't the first time Cassini has photographed our home planet, but this is the first time Earthlings will know in advance that their picture is being taken from a billion miles away.