Hubble Captures Mesmerizing Detail of Two Galaxies on a Collision Course - ScienceAlert

So close that they are categorized under a single name, Arp 91, the spiral galaxies NGC 5953 and NGC 5954 are in the process of merging, with material from the latter extending towards and into the former.

Gradually, the two galaxies will join together, becoming one big elliptical galaxy, according to our models of these colossal cosmic interactions.

Arp 91 is at a stage where the two galaxies haven't yet been significantly disrupted; their spiral structures are still largely intact.

However, their interaction has triggered a burst of star formation in both galaxies, as inflowing gas generates shocks in clouds of molecular star-forming gas, pushing it into denser clumps that collapse under their own mass to form baby stars.

Eventually, the two will merge, their spiral structures dissolving into a bright, nearly featureless type of galaxy called an elliptical galaxy.