The daily ablation of about 30 tonnes of
interplanetary dust is the source of metal atoms and ions in the earth’s upper atmosphere. These metallic species are involved in a very
diverse range of phenomena in the mesosphere and lower thermosphere, including:
the layers of metal atoms which are useful diagnostics of the physics and
chemistry of the 75 – 110 km region; sporadic E layers; meteor smoke; and noctilucent clouds. This seminar will begin with a general
tutorial on the upper atmosphere, and then discuss each of these four phenomena
in turn, focusing on how laboratory studies are crucial in understanding them.