As a result, it is the least-understood part of the atmosphere, resulting in the humorous moniker ignorosphere. The presence of red sprites and blue jets (electrical discharges or lightning within the lower mesosphere), noctilucent clouds, and density shears within this poorly understood layer are of current scientific interest. On February 1, 2003, broke up on reentry at about altitude, in the lower mesosphere, killing all seven crew members. Phenomena in mesosphere and near space Airglow Atmospheric tides Ionosphere Meteors Noctilucent clouds Polar aurora Sprite (lightning) Upper atmospheric lightning (Transient luminous event) See also Aeronomy Amateur radio high-altitude ballooning Geospace High altitude References External links Description with links to other atmospheric topics Students And Teachers In Near Space Near Space Systems Space Data Corporation The B.H.A.L.D.I. Project Atmosphere Atmosphere of Earth