Holograms are pretty cool, sure. But they're still just two-dimensional projections that hover in the air, and as soon as you step to the side, the magic disappears, revealing how flat the thing really is.

But now researchers from Brigham Young University have demonstrated they can create fully three-dimensional projections of moving images - and they use light and particles in the air to achieve this.

The end result is closer than ever to the miniature Princess Leia projection in Star Wars: A New Hope, and that's no accident.

"We refer to this colloquially as the Princess Leia project," said lead researcher Daniel Smalley.

"Our group has a mission to take the 3D displays of science fiction and make them real. We have created a display that can do that."