Photons, spacecraft, atomic clocks and Einstein - fundamental physics in the space environment by UCL Sound published on 2011/12/01 11:39:01 +0000 UCL Lunch Hour Lecture: Photons, spacecraft, atomic clocks and Einstein -- fundamental physics in the space environment Professor Marek Ziebart (UCL Space Geodesy and Navigation) Date: 27th October 2011 Satellites designed, built and launched by humans orbit the earth to carry out a myriad of tasks, friendly and hostile, commercial and scientific. Many of these missions supply critical data to model, mitigate and predict planet-scale processes such as El Nino events, sea level rise, plate tectonics and the earthquake cycle. The spacecraft move at between 4 and 8 kilometres per second, and are between 500 and 20,000 km above the earth's surface but for scientific purposes we need to know where they are to within a few centimetres, and we need to know the time they transmit their signals at the nano-second level. This lecture explains how that is achieved using concepts from fundamental physics. UCL is consistently ranked as one of the world's top universities. Across all disciplines our faculties are known for their research-intensive approaches, academic excellence and engagement with global challenges. This is the basis of our world-renowned degree programmes. Visit us at www.ucl.ac.uk.