Tracing magnetism back in time

At Geocentrum researchers keep tabs on the Earth’s protective magnetic field.Their areas of study include whether the magnetic field is showing signs of switching poles – something which has already happened many times in the history of the planet. The researchers recently installed some new equipment which will form a national resource. Professor Ian Snowball shows the way through Geocentrum's corridors to the room where the newly installed device gleams. The air is filled with a strange, metallic noise. The rhythmic squeaking comes from the compressor that cools the inside of the machine. "If you close your eyes, it actually sounds like tropical birds", says Ian Snowball with a smile. There is a surrealistic sense of being in the rainforest.