What is coming toward us?

There was once a spider who lived in a cornfield. . He liked his home and planned to stay there for the rest of his life. One day the spider caught a little bug in his web, and just as the spider was about to eat him, the bug said, "If you let me go I will tell you something important that will save your life." The spider paused for a moment and listened because he was amused. "You better get out of this cornfield," the little bug said, "The harvest is coming!" All the stalks will be knocked down and the corn will be gathered up. You will be killed by the giant machines if you stay here." 


The spider said, "I don't believe in harvests and giant machines that knock down corn stalks. How can you prove this?" The spider grinned and said to the little bug, "I don't believe you," and then the spider ate the bug for lunch.  


A few days later, the spider was laughing about the story the little bug had told him. He thought to himself, "A harvest! What a silly idea. I have lived here all of my life and nothing has ever disturbed me. I have been here since these stalks were just a foot off the ground, and I'll be here for the rest of my life, because nothing is ever going to change in this field. Life is good, and I have it made." 


The next day was a beautiful sunny day in the cornfield. The sky above was clear and there was no wind at all. That afternoon as the spider was about to take a nap, he noticed some thick dusty clouds moving toward him. He could hear the roar of a great engine and he said to himself, "I wonder what that could be?"