What might this dream mean?

I don't usually remember dreams for very long, but this one stands out in my mind. I was gazing at the moon in the night sky when it looked like a lunar eclipse was occurring. As I kept watching the black disc which was covering the moon grew larger and larger gradually until it covered almost the entire sky, blocking out all the stars. Apparently others had also noticed this event in the sky and others were terrified that this thing was coming nearer and nearer and was going to collide with the earth. On the radio the astrophysicists were saying that this was a body of dark matter which was indeed going to hit us but it would pass through the earth without any effects, and this is what did happen except that while it was going through the earth no-one could see or hear anything. Soon it finished passing through the earth and people on the other side of the earth could see the dark disc getting smaller and smaller as it traveled away. What does this dream mean?