Mysterious dark comets discovered near Earth

University of Michigan scientists have discovered that about 60 percent of near-Earth objects may be dark comets, which are mysterious asteroids that contain or once contained ice.

Icarus magazine points out that these comets have the characteristics of both asteroids and comets. These comets are located close to the sun, which allows ice to turn directly into gas, forming a cloud around them and giving them acceleration that is not related to gravity.

Astronomers have studied seven known dark comets and estimate that between 0.5 and 60 percent of near-Earth objects could be dark comets that have no halo but are accelerated by nothing but gravity. They are thought to come from the inner asteroid belt, and objects in this belt contain ice.

Researchers believe that these comets begin to rotate rapidly after losing ice, and this condition may lead to their disintegration into small bodies that continue to lose ice and accelerate. This explains their small size and high rotation speed.