Supernovas blast iron into interstellar space

Supernova explosions are a crucial step in the chain of events that generates the iron we find in interstellar space and in the Solar System, including on Earth.

Iron is formed via nuclear fusion in the cores of stars that are eight times more massive than our Sun.

The life of a massive star takes a different course from that of lower-mass stars. Only in a massive star is the weight of the outer layers sufficient to fuse nuclei of lighter elements into iron ones. Because of its huge mass, the inward gravitational pressure in a massive star’s interior causes a chain of nuclear reactions that, starting from hydrogen, ultimately leads to the formation of iron.

When the nuclear fuel eventually runs out, the core of a massive star collapses violently, while its outer shells are blasted away with monstruous energy in what we call a ‘supernova explosion’.

In this way, a huge amount of material rich in dust and heavy metals, including iron, is blown out into interstellar space.

Our Solar System formed from the collapse of a cloud of dust and gas enriched by material from supernova explosions. Swirling in a disc around our infant star, the material containing heavy elements gradually clumped together into the planets. Oxygen, silicon, aluminium and iron ended up as the main ingredients of Earth’s crust.

Iron on Earth was captured by the cells of living organisms, such as our blood cells that use it to transport oxygen. Iron, a vital ingredient of our blood, was minted in massive stars.

[Image description: The image shows an infographic organised into six parts, numbered one to six. On a black background, we have: 1. a yellow-gold ball with interior shells; 2. a violent explosion, bright white at the centre and yellow-gold-orange at its periphery; 3. blue atoms floating in space; 4. and 5. an orange-gold disc of gas, pebbles and round grey-brown balls swirling around a source of very bright light; 6. a petri dish with red blood cells that look like round and flat jelly sweets.]