You must have heard a lot about this in sci-fi movies but what if we tell you that there is a time machine that can provide accurate information of objects which were there about a 750 thousands year ago.
Amazed! But this is true and this time machine is the frozen ice in the glaciers. This is one of a kind time of earth and nature. Ice core is found in glaciers of Antarctica, arctic and Greenland and other glacial areas. At these places every year snow covers the snow that has already been there and this forms a layer, this process has been going on for thousands years now. These layers are known as ice sheets. A cylindrical piece taken out of these ice sheets vertically downwards is known as ice core.
Ice sheets have to be drilled up to thousands of meters to get the core. An ice core can be compares to the rings on the tree. The age of ice core can be accurately determined by the counting of rings in the ice sheets. In 2003 an ice ore with 750 thousand layers (750 thousand years old) was drilled out.
The ice cores are studied in labs with temp below zero degrees centigrade. Scientists investigate the samples for radioactive particles and air bubble b/w these layers. We can get details how the transformation took place by closely investigating it layer by layer.