Fish from nowhere?

Where do fish come from? That might seem a stupid question, but when a new pool forms, unconnected to any rivers, fish sometimes appear, seemingly from nowhere. Nobody has put fish in the pool. The pool is not connected with any other waterways that have fish. Yet after a few months or years, there are…

Messing up the world for 2,500 years

We hear a lot about pollution and particularly what we are doing to the atmosphere. It seems we have been doing it for a very long time. Ice core samples from Greenland show raised levels of lead in the atmosphere beginning around 500BC. This is the earliest evidence of anthropogenic (human-caused) pollution. It was produced…