Scientists at the University of Nottingham have developed an anti-gravity machine that can float objects in mid-air. Back to the Future here we come. Using liquid oxygen to boost the buoyancy of a powerful magnet, they have successfully levitated stones, coins and lumps of metal. The team have identified a safer mixture of liquid nitrogen and oxygen for floating heavy objects, making commercial applications of the technology possible. The science behind the research could be used in mining to filter diamonds from rock and soil, while US space agency NASA is reported to be interested in the technology for zero gravity research.