 It is not easy to visualize times that stretch over billions of years. The numbers are so big that they don't mean anything! Instead, let's look at an analogy that might help to bring the enormous time frame of the universe into perspective. The earth was formed 5 billion years ago. Imagine that the length of time from then until now is represented by the length of a football field, 100 metres. You are at one end.  On this scale, the first simple life forms, multi-celled organisms in the ocean, appeared at about the 40 m line. This was 3 billion years ago. Next came the first primitive fish (still no land life) at the 92 m line, or 425 million years ago. The dinosaurs flourished about 140-200 million years ago...this is at about the 95 m line. The first primitive ancestor of humans appeared about 5 million years ago. On our football field, this happens merely 10 centimetres from the end line! All of recorded history, the last 5000 years or so, takes place in the last tenth of a millimetre. Your lifetime, assuming you are less than 50 years old, happens in the space of only one two-thousandth of a millimetre, too small to see without a microscope, right at the very end of the field. |