Solar activity can affect re-entry of UARS satellite
Friday, September 23, 2011 - 09:30
in Astronomy & Space
The world's eyes are on the Upper Atmosphere Research Satellite (UARS) headed toward re-entry into Earth's atmosphere. The satellite is currently predicted to re-enter sometime on the afternoon of Friday, September 23, 2011, but it hasn't been easy to precisely determine the path and pace of UARS despite the fact that scientists well understand how satellites move through space. The problem lies in the fact that space itself changes over time -- the upper layers of Earth's atmosphere can warm up and, more importantly, puff up in response to incoming energy and particles from the sun.