Everything in the universe is kept in line by some powerful forces. How these forces work together in harmony has proven tricky to figure out. But scientists have an idea: string theory.
So what are these forces? Gravity, which keeps things tied to the planet. Electromagnetism, which keeps bunches of atoms together. Strong nuclear force, which keeps the core of an atom together. And weak nuclear force, which makes the core of an atom fall apart.
How these forces work together is called the theory of everything, which we haven't yet cracked but string theory is a strong contender.
The problem scientists faced was how to explain how the universe works on the gigantic scale of planets (where gravity is the star of the show) and how it works on the scale of particles so small that we can't even see them (where those other three all-powerful forces come into play).
Enter string theory. There are strings we’ve all heard about, like the strings of material that make up your clothes. Scientists suggested that if you look close enough you’d find everything in the universe, from gigantic planets to tiny particles, is made of strings.
From a distance these strings look like particles. But when you zoom in they’re actually loops. The great thing about loops of string is that when they get shaken up – or vibrate – they can take on a whole of host of different shapes. In string theory, these differently shaped loops have different jobs, which can explain how each of the four different forces that run the universe work.
We don't yet have the technology to see these strings, so for now the jury is still out.