Oort cloud

Oort cloud, made of icy, comet-like objects, surrounds the Sun, planets and Kuiper Belt objects. According to a new theory by Harvard University scientists, it may be the source of the Chicxulub impactor that caused global extinction of dinosaurs. Numerous long-duration comets were influenced by Jupiter’s gravity, which pulls them inwards. During this close approach, a type of gravitational perturbation called tidal disruption may have caused impactor to reach the Earth.