Fruit flies levitated to aid astronaut research

Posted by Kate Taylor

A team of scientists at the University of Nottingham has been levitating fruit flies to investigate how biological organisms are affected by weightless conditions in space.

While levitating creatures with wings might seem like cheating just a little, they say they've observed the flies walking in the air, and more quickly than they do on the ground.

The flies have previously been observed to behave the same way in experiments on the International Space Station.

"It is unfeasible to apply this technique to investigating the effects of weightlessness on a human being directly: no magnet exists that can do this. However, by studying the effects on ‘model’ organisms such as the fruit fly, we can hope to obtain information about the effects of weightlessness on particular biological mechanisms," says Dr Richard Hill of the University’s School of Physics and Astronomy.

"It’s also important to remember that, in our future endeavours to explore space, setting up permanent bases on our Moon, or Mars for example, or other planets, it will be crucial to understand the effects of weightlessness on all living organisms: our long-term survival will of course require us to take with us many different biological organisms."

In the type of magnetism called diamagnetism, objects are weakly repelled from magnetic fields. The researchers used the university’s powerful superconducting magnet to produce a very strong magnetic field of around 16 Tesla — approximately 350,000 times stronger than the strength of the Earth’s field.

Inside the superconducting solenoid magnet, the diamagnetic repulsive force on the flies can be large enough to just balance the force of gravity so that they levitate with no support.

"Crucially, as far as living organisms are concerned, the levitation force balances the force of gravity right down to the molecular level," says Hill.

"This means we can compare the levitation force, which balances the force of gravity in our magnet, with the centrifugal force that balances the force of gravity on an astronaut in orbit around the Earth."

Hill says the team doesn't yet know why the flies move more quickly. It may be because the flies just find moving around in weightlessness easier on their joints and muscles, or else a response to confusion about which way is up or down.

There's a video, here.