There's an ancient joke about the end of the world.
An astronomer is giving a talk to a community group and he says that in 5 billion years the sun will expand and engulf the earth, ending life as we know it. At this a woman in the back leaps for her chair shouting "Oh my God! Oh my God!", and then faints.
They revive her and the astronomer says, "Well, gee, I know that I said the world will end, but it's a long way off. Don't worry."
And the woman says, "Well, what did you say?"
And the astronomer says, "I said the world will end in 5 billion years."
And the woman says, "Oh! Thank God! I thought you said 5 million years."
People have been predicting the end of the world for a long time, and we still find it believable. Just a few years ago everyone was exercised about the end of the Mayan calendar, which would spell finish to our planet; before that there was the Y2K debacle, in which our technology would finish us off in a massive computer meltdown that never occurred. And so on. Regularly people predict the end of the world as we know it, and we go on feeling fine.