Meteor showers and their parent comets

In recent years, it was discovered that meteor showers are younger than thought before. Meteor storms, such as the Leonids. are caused by dust grains (called meteoroids) ejected just a few revolutions ago. Meteoroids can be dragged along and ejected by the flow of (:water) vapour, each time when the comet is near the Sun and the heat of the Sun evaporates ices. The most recent development is that many of our short-period annual showers also appear to have been created in the last one or two thousand years. In these case5. there is mounting evidence that the meteoroids were ejected during a comet fragmentation event:. at random positions along the comet orbit.