Can't get to England to see the last total eclipse of the millennium? Not to fret, perhaps you can listen in for it instead.

The passage of the moon between the Earth and sun happens noiselessly enough, but blotting out the daylight should have a distinct effect on our atmosphere. Ultraviolet radiation from the sun zaps molecules in the upper atmosphere, called the ionosphere, freeing electrons.

The ionosphere acts like a mirror, capable of bouncing radio waves over long distances. During the day, shorter wavelengths can't bounce as well through the layers of the ionosphere, but at night, when electrons recombine with molecules and the ionosphere thins, short wave radio signals can return to Earth.

On Tuesday, as the moon's shadow falls across Europe, blocking out the sun, short wave radio stations may suddenly be able to skip across the horizon and be heard across the ocean.

NASA has put out a call to all radio enthusiasts to tune in to the BBC World Service or Europe's Voice of America, both of which have transmitters in or near the path of the total eclipse. Participants are invited to email their results to NASA, which will compile the information and pass it along to scientists interested in atmospheric physics.