Stellar clusters are common. Globular clusters contain some of the
oldest stars, whilst the youngest stars are found in OB associations
or in other clusters associated with recent star formation.
Such crowded places are hostile environments: a large fraction
of stars will collide or undergo close encounters. I will explain how
stellar
clusters are factories for producing exotic objects, including
black holes and neutron-star binaries. I will also discuss how planetary
systems similar to our own solar system are vulnerable to breakup
due to close encounters by passing stars. Thus by studying stellar
clusters
we will learn more about the rarity of planetary systems similar to our
own solar system.
