Imagine a world where encrypted, secret files are suddenly cracked open - something known as "the quantum apocalypse".
Put very simply, quantum computers work completely differently from the computers developed over the past century. In theory, they could eventually become many, many times faster than today's machines.
That means that faced with an incredibly complex and time-consuming problem - like trying to decrypt data - where there are multiple permutations running into the billions, a normal computer would take many years to break those encryptions, if ever.
But a future quantum computer, in theory, could do this in just seconds.
Such computers could be able to solve all sorts of problems for humanity. The UK government is investing in the National Quantum Computing Centre in Harwell, Oxfordshire, hoping to revolutionise research in the field.
But there is also a dark side.
I can think of more immediate things to be scared of, if you're the easily scared type. To read more, click here.