Peter Tyson, Nova Online producer at PBS, has written a fascinating article on ice cores and asks the question:  ”How would you like to have a time machine that could take you back anywhere over the past 300,000 years? You could see what the world was like when ice sheets a thousand feet thick blanketed Canada and northern Europe, or when the Indonesian volcano Toba blew its top in the largest volcanic eruption of the last half million years. ”

“Well, scientists have such a time machine. It’s called an ice core. Scientists collect ice cores by driving a hollow tube deep into the miles-thick ice sheets of Antarctica and Greenland (and in glaciers elsewhere). The long cylinders of ancient ice that they retrieve provide a dazzlingly detailed record of what was happening in the world over the past several ice ages. That’s because each layer of ice in a core corresponds to a single year–or sometimes even a single season–and most everything that fell in the snow that year remains behind, including wind-blown dust, ash, atmospheric gases, even radioactivity.”

Read and see more on PBS.

Photo by Natural Environment Research Council.