It was one of the most interesting — and perhaps one of the most important — technological developments of the year. The trouble is that no one can really explain what it is that Google built, at least not in a way that mere mortals can understand.

The first thing you need to know is that a quantum computer is experimental technology. It won’t be ready for prime time for several more years, if not more. But experts believe it will eventually make today’s computers look like toys, handling tasks that would never be possible with traditional machines.

It will do this by harnessing the power of quantum mechanics, which is the strange behavior exhibited by things like electrons or particles of light or exotic metals cooled to several hundred degrees below zero.

Describing this strange behavior is difficult, because it is unlike anything any of us have ever experienced. If any of us actually looked at the fundamental building block of a quantum computer, called a qubit, it would cease to be a qubit.

Got that?

We asked several top experts to describe a quantum computer in terms anyone can understand. And because attention spans are short these days, we asked them to pack their explanation into 280 characters, or the length of a tweet.