December 2, 2008 Until November, Tristan da Cunha was home only to 271 people, a small flightless bird, and a piece of land named Inaccessible Island. Now the world's most remote inhabited archipelago is host to a Danish Observatory designed to help improve our understanding the Earth’s weakening magnetic field and the way this affects satellites.
Tristan da Cunha was chosen as the location for the observatory because it is located in the middle of a region known as the South Atlantic Anomaly, where our planet’s magnetic field is unusually weak. While the global magnetic field is weakening by 5% every century, the magnetic field in the SAA region is lowering at ten times the speed. One of the effects of a diminished magnetic field is a higher exposure to radiation, which is disruptive to the operation of artificial satellites and orbiting spacecraft, including the ISS and Hubble.
“Until now, Denmark has mostly been involved in projects that measure the magnetic field from space, with the Ørsted satellite and the future Swarm satellite mission, as well as the measuring stations in Greenland,” says Professor Nils Olsen of DTU Space. “With the observatory on Tristan da Cunha, we will have a measuring station in the Tropics right in the middle of the South Atlantic Anomaly, where the strength of the magnetic field is only half as high as in Denmark.”
“Opening the observatory is a milestone in our research,” says senior researcher Jürgen Matzka from DMI, who is heading the project. “Finding a suitable location for the cabin on the island was a major logistical challenge, and we had a lot of help from South African colleagues and the French firm of engineers EnviroConsult. The cabin is also built exclusively of wood and brass in order not to disturb the magnetic measurements.”
The observatory is a partnership between DMI, the Danish Meteorological Institute, and DTU Space, the Danish National Space Institute.