The Cosmic Waltz: Galaxies Collide, Stars Form, and Supernovae Explode

Galaxies are not shy about bumping into each other in spectacular fashions, remodeling one another through cosmic collisions.

Two spiral galaxies, IC 2163 and NGC 2207, are slowly colliding, creating a stunning cosmic spectacle. The impact has already left visible marks on the galaxies, elongating their arms into long structures due to tidal forces.

Webb's mid-infrared images reveal red shock fronts and “eyelids” around IC 2163, showcasing the extreme gravitational force and incredible shape deformation. As time progresses, the galaxies will continue to interact, further altering their appearances.

One spectacular consequence of the galactic collision is the increased rate of star formation. Together, IC 2163 and NGC 2207 are generating an estimated two dozen Sun-like stars per year, significantly faster than the Milky Way's average of two to three stars annually.

The enhanced star formation is directly influenced by the gravitational forces of the collision, which compress and collapse the gas and dust within the galaxies, triggering new star formation. Hubble ultraviolet imaging and Webb mid-infrared data show cool cores of star formation.

Blue areas observed by Hubble represent the stars and birth of new stars, while pictures taken by Webb show regions of high activity in shades of pink and white. These stellar nurseries are superstar clusters in the upper spiral arms of NGC 2207 and mini starbursts randomly distributed across both galaxies.

They are the sites where stars are being formed in spectacularly rapid succession, as if the galaxies are competing to create an ever-increasing number of new stellar objects. In addition to these active star-forming regions, at least seven supernovae have occurred in the galaxies over the past few decades.

Every supernova plays a crucial role in the evolution of galaxies (just like this Sombrero galaxy, which has a mysterious glow). Explosions clear out space in the galactic arms, redistributing the nearby gas and dust and concentrating the new star formation in the gaps left behind. These stellar eruptions significantly impact the ongoing evolution of these galaxies.

As IC 2163 and NGC 2207 continue to interact, their gravitational pulls will shape their arms, cores, and overall appearances. Eventually, their forms may merge, leaving a single galaxy with a luminous core—an even brighter “eye” than we witness today.

However, the stellar formation rate will gradually decrease as the gas and dust residuals are depleted. The exhaustion of stellar-forming gas will lead to a reduction in the galaxy growth rate. The roaring of stellar formation will subside, and the once-energetic galaxies will settle down into more quiescent, less dynamic structures. This transformation is an inherent part of the evolution of galaxies that have experienced strong gravitational interactions.

The captivating images of IC 2163 and NGC 2207, obtained by the James Webb and Hubble telescopes, respectively, showcase the universe's beauty and complexity. These galaxies' blood-dripping “eyes” symbolize the eternal cosmic waltz, where dying meets living in the creation of the cosmos.

Through advanced telescopes, we get a glimpse of the forces of gravity, star formation, and supernovae at work, crafting the destiny of galaxies. This cosmic play continues to unfold, offering rich opportunities for unraveling the universe's secrets (like the historic find found by the JWST on Question Mark Galaxy).