Stephen Hawkings has gone on record to say that we should avoid making contact with aliens until we are as technically advanced as they are. His views echoes what happened in the film Independence Day. The film had aliens arriving on Earth and destroying everything in their wake. He believes that they have destroyed their home world and now are looking at a new home and they probably don't want to cohabit with us. He cites history where Europeans travelled to the new worlds and conquered and killed the natives. Its a case of not hello to E.T. but being prepared for the creatures from Independence Day and V.