The history of the Earth is written in its stones. While the are still unanswered questions, the overall history of our planet from the Palaeozoic Era up to today is recorded in fossil remains. This was the age of ancient life, 605 million years ago, when the only creatures in the warm and shalllow seas were worms, jellyfish and other backboneless animals. The continents then were still joined together in a single large landmass that has been named Pangea.

Even then some of the sea creatures were using lime to build shells for protection and support. The development of internal skeletons came later, with the first fish. Later fish had lungs and lobe-like fins that could be used to support them when they emerged from the sea and ventured onto the land. From these the amphibians developed about 290 million years ago, the ancestors of the first reptiles.

The first dinosaurs appeared on Earth just over 205 million years ago. By the time the first sea-filled cracks were appearing in Pangea 200 million years ago, the dinosaurs had spread all over the world, to every part of the first giant continent that would later separate into the smaller continents we know today. This was their world, where they filled every ecological niche, and their rule was absolute for 135 million years.

It took a worldwide disaster to disturb their dominance. A ten-kilometer-wide meteor that struck the ocean and hurled millions of tons of dust and water high into the atmosphere. The dinosaurs died. Seventy percent of all species then living died. The way was open for the tiny, shrew-like mammals—the ancestors of all mammalian life today—to develop and populate the globe.

It was galactic chance, the dice-game of eternity, that this great piece of rock hit at that time, in that manner, and caused the global disturbance that it did.

But what if it had missed? What if the laws of chance had ruled otherwise and this bomb from space had not hit the Earth? What would the world be like today?

The first and most obvious difference would be the absence of Iceland, for these volcanic islands mark the place where the meteor struck and penetrated to the mantle below.

The second greatest difference would be in the history of global climate, still not completely understood. We know that different ice ages came and went—but we do not know why. We know that the polarity of the Earth has changed in the past, with the north magnetic pole where the south is now—but we do not know why. It seems a certainty that if the meteor had not hit and the incredible atmospheric change had not occurred, that the same progression of ice ages and accompanying continent building would not have occurred in precisely the same manner.

Look at our world as it might have been.