The illusion technique known as Pepper’s ghost had its stage premier in Charles Dickens’s The Haunted Man in 1862. Modern audiences may be more familiar with this device in BBC’s Sherlock (the ghost of Emelia Ricoletti in ‘The Abominable Bride’) or on the Hogwarts Express attraction at Universal Studios Florida, where people ‘disappear’ through a brick wall onto Platform 9 3/4. It’s a simple trick involving a mirrored image that can suddenly appear or disappear depending on the relative level of lighting between the object and the image. And now it’s possible to witness star formation in 3D, thanks to the StarFormMapper team.

Credit: Royal Astronomical Society/Kate Arkless Gray

The picture shows a 3D star being created by an upside-down perspex pyramid on top of a special monitor that displays four separate images; these are reflected into the centre of the pyramid to form a mesmerizing 3D hologram. The StarFormMapper project studies star and star cluster formation using simulations as well as ever-increasing amounts of observational data coming from ESA’s Gaia and Herschel missions. The team have also created a smaller version of their apparatus to take to schools, festivals and other public events. It was unveiled at the Royal Astronomical Society’s National Astronomy Meeting in Lancaster in July 2019.