The universe is home to millions of galaxies and this is one fact that has fascinated astronomers for a long time and they keep studying them to uncover the latent mystery. However, some galaxies are not just about sparkling stars and deep mystery.

They possess signs of impending doom, reports Forbes. Some of the galaxies can collide with each other. Well, galaxy mergers and collisions sounds difficult to believe, some galaxies can take this path because of their unique structural dynamics. It does not matter if they are millions of light-years away from each other, they are so closely knit that they can end up colliding and thus, merging together to become a single entity.

The universe is home to many such galaxies that are found to be tightly grouped together. However, some of them are unusually close together and they are known as compact groups. These collections are many in number and it was astronomer Paul Hickson, who first cataloged them in 1982.

One such galaxy goes by the name of Stephan's Quintet and is also known as Hickson Compact Group 92. It is home to four galaxies that have been bound by the force of gravitation and are still in the process of merging with another closer galaxy that is smaller and younger. There are many other such galaxies with similar Hickson Compact Group nomenclature, in honor of their founder.

Comprising spirals and ellipticals, a number of galaxies in these groups possess asymmetrical shape and their rates of electromagnetic emissions are also higher than the normal standard. This is because gravitational interaction takes between gases within the galaxies, which causes star formation. Infrared and radio emissions could also turn on a central black hole.

The motion of these galaxies is dominated by dark matter, within the group as well as the individual galaxies. The compact groups, as said before, are numerous in number, but they have a very short shelf life. This is because gravitation will ultimately force them to blend into a single galaxy.

However, this does not apply to all. Those groups that carry random non-gravitational alignments will survive longer.