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...

OSSE was used to measure the longitude and latitude distribution of positron annihilation in the inner galactic ridge using diierential measurements relative to intensities at latitudes of 10. An improved understanding of the 50 keV to 10 MeV continua has recently permitted accurate determinations of the positronium continuum ux intensities; this provides an 5 times greater signal than was avai...

Abstract In this paper numerical simulations of the Earth’s magnetic field in south-eastern part an Najaf-Karbala Plateau and to north centre An-Najaf governorate have been investigated using WMM2015 model. The study area is located at (Latitude = 32.3180°-31.99°) N, (Longitude 44.5160°-44.0690°) E, ranging altitude between 20-90 m above sea level). was divided into grid (2000 points) by drawin...