We are all made of
stardust

There are many different types of atoms. You probably can name many of them already, such as oxygen, calcium, carbon and iron. We call them elements. And everything on this planet is made up of various combinations of these elements. Including you.

But what has this got to do with stardust?

Well, almost all atoms are formed in gigantic cosmic atom forges. Otherwise known as... stars.

Periodic Table

Scientists arrange elements into something called the Periodic Table.

Hung in every science classroom in the world, it's one of the most remarkable achievements of 19th century science. It was developed by a Russian chemistry professor, Dmitri Mendeleev, and it classified elements according to their atomic weights and how they interact with each other. Although there had been earlier attempts to organise elements, Mendeleev's table had two advantages. Firstly, he left gaps where it seemed that there were elements missing – therefore predicting properties of elements such as gallium and germanium long before they were discovered. And secondly, in certain instances, he switched adjacent elements on the chart allowing elements to be grouped into families, such as halogens or noble gases.

When the universe was young,

13.7 billions years ago, the only elements that existed were the simplest ones: hydrogen and helium. Over time, as the universe aged, these elements formed clouds of gases, pulled together by gravity.

The gas clouds became so dense and hot that hydrogen atoms began to fuse together to form the bigger element, helium.

When elements fuse a huge amount of energy is released. This reaction is how all stars work. It's how our sun works.

Nuclear Fusion

Stars join elements together in a process called nuclear fusion.

Our nuclear power stations do the opposite; they take very heavy elements, such as uranium, and split them apart. This is called nuclear fission, and it also produces fantastic amounts of energy. However, fission reactors produce radioactive waste, which can be dangerous and difficult to dispose of. The waste from a fusion reactor would be far safer.

Stable fusion reactors are currently beyond our scientific know-how, but huge, international research teams are hard at work on the problem. A breakthrough in this area could mean safe, green energy for the planet.

As a star ages...

it will eventually run out of hydrogen atoms in its core to fuse together. At that point it starts fusing the larger helium atoms, which it had created earlier, to make heavier elements. This gives out even more energy. And when the helium runs out, the star continues to fuse heavier and heavier elements together always growing in size and temperature. It keeps creating heavier elements – lithium, beryllium, carbon – until finally, it reaches iron.

At that point, the star becomes unstable.

Small stars can die many different ways. But huge stars – stars eight times bigger than our sun – are destined to die in a violent explosion called a supernova. In only a few seconds, the star collapses from a diameter of 10 million kilometres to only a few dozen kilometres. At the same time, there is a short but massive burst of heat. And it is in this burst that elements heavier than iron are fused together.

Observing the Sun

Scientists have a number of amazing methods to observe our nearest star.

For instance, right now, orbiting the Sun, are two spaced-based observatories called STEREO. Using the two different vantage points from these observatories scientists can examine the structure and evolution of solar storms as they explode from the surface of the sun and drift out into space.

The explosion of the star...

The explosion of the star sprays all of these newly forged elements out into galaxy. And eventually, enough of them might clump together and start to form a planet. Perhaps very much like our own.

Almost every material and resource...

Almost every material and resource we know of was created from elements born in stars, including those found in living creatures – which means you.