Galaxy Season

Spring is Galaxy Season for astrophotographers. As the equinox turns, our night sky faces away from the crowded disk of the Milky Way, peering through a clear ‘galactic window’ into the deep void. While our own galaxy is a tapestry of nebulae and dust, looking ‘up’ out of the plane reveals a riotous family portrait of entire worlds, coined “Island Universes” by the great astronomer Hubble.

This image was taken of the Coma Cluster. Not a cluster of stars, but a dense group of galaxies clustered together. Even though you can count thousands of galaxies in this photo (each smudge of light that is not a point of light is a galaxy), it pales in comparison to the billions of galaxies in the visible universe. And, think that each galaxy is a universe unto its own, filled with billions of stars and even more planets.

This cluster was studied by Fritz Zwicky in the 1930’s and he discovered that something hidden is keeping the galaxies from flying apart and coined the term “Dark Matter” (“Dunkle Materie”). To this day, almost 100 years later, we still have no idea what Dark Matter is.

The Coma Cluster isn’t just a random group; it’s the central hub of the Coma Supercluster, which is a major component of the “Great Wall”—one of the largest known structures in the observable universe. And recent discoveries about galactic “streams” or “filaments” show how vast filaments of superheated gas and dark matter—the ‘tendrils’ of the Cosmic Web—act as intergalactic highways, bridging the immense voids to connect these clusters into a single, unified structure.^[1] It’s as if the cosmos is a giant network of connected nodes of mass and energy, similar to neuronal connections in a brain.

Some ponder the vastness of the cosmos and feel insignificant, puny, and of little consequence. Others like me are inspired by being a part of something truly magnificent and beautiful. Sometimes our own hubris prevents us from acknowledging that we actually know little of the big picture and the meaning and purpose of a gigantic cosmic playground. If there is any insight to be gleaned it is that everything truly is connected, as above so below. So sit back, enjoy the ride and the view into the galactic void as we explore galaxy season this Spring.

^[1] Migkas, K., et al. (2025). “Observation of a 23-million-light-year cosmic filament bridging galaxy clusters in the Shapley Supercluster.” Astronomy & Astrophysics.