In the case of Melancholia, you have a newly identified stray planet dancing in the Earth's orbit until it decides the dance is over (see image to right). This makes for a very dark movie, not to say the action before the disaster gives us any reason to be cheering for Earth. The film is beautiful to watch. Ultimate destruction has never been so amazing. And where did this new planet come from? We don't get much from the movie, though is was not really intended as a scientific film. One character does make an interesting comment noting that with the extinguishing of life on Earth all life will disappear from the universe. But I think that's the depression talking.
Another Earth is a quirky film on the appearance of a mirror Earth slowly arriving and then pairing up with our Earth. Again, this is not intended as a scientific film but rather a statement about possibilities and how things could be different if one event in a life were to change. Hence, planets are backdrops to stories rather than the main characters. That is fine in itself. But we need to be adventurers acting on the universe to learn more this world of ours. We do not want to sit here waiting for the universe to come to us, maybe with disastrous consequences. Colonies in our solar system and elsewhere can protect us from an extinction event like Melancholia. And I too am interested in other Earths, but they will be found on a much more distant horizon using telescopes that will entail millions if not billions of dollars in expenditures. Disney spent $250 million on a dud movie about travel to Mars in John Carter, while we earthlings continue to ponder whether or not we really have the funds and ambitions to make a trip to Mars a reality. I look forward to more hopeful movies that dream about space missions beyond our small, blue planet. And, just as importantly if not more so, I look forward to steps that will turn these dreams into reality. To go where no man has gone before (sorry, I could not help myself).