What goes up no longer has to come down. British scientists have developed an antigravity machine that can float heavy stones, coins and lumps of metal in mid-air. Based around a powerful magnet, the device levitates objects in a similar way to how a maglev train runs above its tracks.
Peter King, a physics professor at Nottingham University, said: "We can take an object and float it in mid-air because the magnetic forces on the object are enough to balance gravity."
The device exploits diamagnetism. Place non-magnetic objects inside a strong enough magnetic field and they are forced to act like weak magnets themselves. Generate a field that is stronger below and weaker above, and the resulting upward magnetic force cancels out gravity.
Scientists have used diamagnetism to make wood, strawberries and, famously, a living frog fly. "That force is strong enough to float things with a density similar to water, but not things with the density of rocks," Prof King said. To make their machine more powerful, the team added an oxygen and nitrogen mixture, a paramagnetic fluid. Inside the magnet, the mixture helps objects to float.
The researchers, who announce their results today in the New Journal of Physics, are working with Rio Tinto to develop the technique to sort precious stones from soil. The US space agency Nasa is also interested as it offers a cheaper way for zero gravity research.
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