Forces are what make objects interact and move other objects. They are all around us, pushing and pulling everything in the universe. In the distant past we thought there was only one kind: the pushing physical force of things touching other things. The more we understood about the world, the more forces we discovered, and we learnt that forces can act in different ways and have effects even without physical contact.
Now we know about gravity, an attractive (pulling) force which affects everything in the universe that has mass, keeps the Earth orbiting the Sun, and the Sun orbiting the galaxy. In honour of Sir Isaac Newton, who first described gravity as a force, the strength of all forces is measured in newtons.
There is also the electromagnetic force that affects things that have an electrical charge or are magnetic. This force is actually a result of ‘photons’, the particles that we normally call ‘light’ and can be both attractive and repulsive. We make use of the electromagnetic force everywhere there is electricity, so understanding it has become vital for the modern world.
Deep inside atoms we have discovered other forces that we never notice in everyday life, the weak nuclear force and the strong nuclear force. However, without these forces acting on weird sub-atomic particles like quarks and leptons, the Sun wouldn’t produce energy and atoms wouldn’t be able to form.
In this zone there are scientists who research what happens when we look at forces in extreme conditions and strange situations. One scientist looks at how distant galaxies collide under their huge gravitational forces, another at what the core of the earth is like deep beneath our feet at massive pressures and temperatures, and one wants to find out if the sun and other stars experience star-quakes. One scientist is thinking about how sub-atomic particles behave when you make them as cold as possible, and another is using lasers and the electromagnetic force to defend aircraft from attack.