Quantum physics

Wave-particle duality is an example of superposition(opens in new tab). That is, a quantum object existing in multiple states at once. An electron, for example, is both ‘here’ and ‘there’ simultaneously. It’s only once we do an experiment to find out where it is that it settles down into one or the other.

This makes quantum physics all about probabilities. We can only say which state an object is most likely to be in once we look. These odds are encapsulated into a mathematical entity called the wave function. Making an observation is said to ‘collapse’ the wave function, destroying the superposition and forcing the object into just one of its many possible states.

A telescope(opens in new tab) can focus light waves from distant stars, and also acts as a giant light bucket for collecting photons. It also means that light can exert pressure as photons slam into an object. This is something we already use to propel spacecraft with solar sails, and it may be possible to exploit it in order to maneuver a dangerous asteroid off a collision course with Earth(opens in new tab), according to Rusty Schweickart, chairman of the B612 Foundation.

It’s a theory of quantum physics yet to be adequately explained, and you’ll probably find many explanations online. IP physics tuition teachers will be able to help you better understand this principle.