It’s difficult to get a grasp on millions or billions of years but at least you can
get some sense of proportion. Preparing to lead a geology walk this afternoon I turned
to Google Earth(new version just out, hope this one behaves better than the last
on my computer!).
The walk starts alongside a playing field which Google Earth reveals to be 650 feet
long. To use this distance as a time scale I worked out that if you take the length
of the playing field to represent the 4.6 billion years of Earth’s history then 1.7
inches would represent a million years.
I’ve marked a ruler to illustrate this time scale: present day is on the left, the
formation of the Earth on the right. The transition from the Carboniferous to the
Permian period 290 million years ago - the rocks we’re looking at this afternoon
- is represented by the red line on the left which on the ground would be just 40
feet from ‘present day’ while the dinosaurs were only three of my yard-long paces
back in time.
Extinction of dinosaurs 65 million years ago
End of Carboniferous 290 million years ago
First complex cells c. 2 billion years ago
Photosynthesis c. 3 billion years ago
First simple cells c. 3.8 billion years ago
IF THE story of Earth, back to its birth 4,600 million years ago, was represented
by the length of a football field then the extinction of the dinosaurs would be just
two or three paces back in time.
I used a field sketch to explain the geological fault we encountered on the walk.
To familiarise myself with the rocks, paleo-environments and industrial history associated
with the site I took a large (A2) layout pad and, starting in the middle, drew cartoons
to remind myself of the key facts. This ‘Mind Map’ technique has been popularised
by Tony Buzanand I’ve started using it again after reading his Mind Maps for Kids
For more on Upton Cutting Regionally Important Geological Site, which we visited
this afternoon, see my previous diary page from November 2007, Tracks through Time.