The Department of Terrestrial Magnetism (DTM) was founded in 1904 to map the geomagnetic field of the Earth. Over the years the research direction shifted, but the historic goal to understand the Earth and its place in the universe has remained the same. Today the department is home to an interdisciplinary team of astronomers and astrophysicists, geophysicists and geochemists, cosmochemists and planetary scientists. These Carnegie researchers are discovering planets outside our solar system, determining the age and structure of the solar system, and studying the causes of earthquakes and volcanoes.