now. this weekend we are starting a new segment called "the science behind." our first topic is saturn, and we'll begin with an unusual question. did you wave at the sky last week? no? well, that's exactly what nasa asked people to do, as the cussinie spacecraft snapped pictures of earth from outer space on friday. a group gathered in new york city to participate in the long-distance photo shoot. cnn meteorologist jennifer delgado joins me live to explain. so, we have got people waving -- >> waving in the sky. >> waving in the sky. >> like, here comes the space invaders, something like that, right? >> what's this all about? >> well, this is actually something that's been going on with cassini. cassinie is the spacecraft that's part of nasa, and its job is basically to orbit saturn as well as mercury. what we have here is a rendering of cassini, and this is actually saturn. we see the rings around. we all know so much about saturn. cassini launched in 1997 and it