Their delicate galactic dance takes place more than 100 million light-years from Earth. The lower galaxy, NGC 5953, is tugging at NGC 5954, which appears to be extending one spiral arm downward.
Arp 91 provides a particularly vivid example of galaxy interactions, which are common and an important part of galaxy evolution. Most astronomers think collisions between spiral galaxies lead to the formation of elliptical galaxies.

These extremely energetic and massive collisions, however, happen on timescales that dwarf a human lifetime. They take place over hundreds of millions of years, so we should not expect Arp 91 to look any different over the course of our lifetimes!

Image credit: ESA/Hubble & NASA, J. Dalcanton; Acknowledgment: J. Schmidt Larger image