In the 1700s, scientists, sailors, engineers and explorers were trying to work out how to navigate east to west at sea. The stakes were high; many lives were lost because sailors could not reliably measure longitude. Eventually, the invention of accurate timepieces allowed sailors to use the time in their current location, and the time at a fixed reference, to calculate longitude. But how do lo...

We measured the mean plane of the Kuiper belt as a function of semi-major axis. For the classical Kuiper belt as a whole (the non-resonant objects in the semi-major axis range 42–48 au), we find a mean plane of inclination im = 1.8 ◦+0.7 −0.4◦ and longitude of ascending node Ωm = 77 ◦+18 −14◦ (in the J2000 ecliptic-equinox coordinate system), in accord with theoretical expectations of the secul...

Context. The majority of stars form in clusters. Therefore a comprehensive view of star formation requires understanding the initial conditions for cluster formation. Aims. The goal of our study is to shed light on the physical properties of infrared dark clouds (IRDCs) and the role they play in the formation of stellar clusters. This article, the first of a series dedicated to the study of IRD...

The convergence of meridians toward the South Pole causes unique problems for geometrical comparison of structural geological and geophysical datasets from Antarctica. The true North reference direction ordinarily is used for measuring and reporting vector data (strike, trend) in Antarctica, as elsewhere. However, over a latitude distance of just 100 km at 85° South, the angular difference in t...