Iron is formed in stars, makes up most of the Earth's core & as a result enables life as we know it to exist, says Prof Allan Blackman from AUT, in ep 41 of Elemental.

Iron is the only chemical element on the periodic table to have one of the Ages of humanity named after it. Iron ornaments dating back to 3500 BCE have been found in Egyptian tombs, but the Iron Age started at different times in other civilisations.

The first use of iron by humans was probably iron found in meteorites, as although Earth is home to lots of iron it is not found as elemental iron, except in meteorites.

The discovery of steel - iron containing a small amount of carbon - ushered in the Industrial Revolution that led to the modern world as we know it.

Iron is, by mass, the most common element on earth, because the inner and outer core of the planet are mostly made of iron.

Molten iron in the core moves, creating an electrical current that causes the magnetic field which shields living creatures from harmful solar radiation.

Iron is important to life on earth in other ways, too - in humans, iron is a vital component of haemoglobin and myoglobin which move oxygen around our bodies. And iron is the reason our blood is red, says Professor Allan Blackman from AUT.

Go to this episode on rnz.co.nz for more details