Stunning image from the James Webb Space Telescope revealing an Einstein Ring formed by two distant galaxies.
Image Credit: ESA/Webb, NASA & CSA, G. Mahler
As we approach 2026, we’re stepping into a year rich with galactic exploration.
We’ll witness the beginning of the Vera C. Rubin Observatory’s deep dive into the space-time legacy, alongside a potential launch of NASA’s Nancy Grace Roman Space Telescope.
Both observatories are pivotal for galaxy observation, aimed at cataloging and unraveling the complexities of galaxy structures and behavior. Expect significant updates on galactic findings in the upcoming months!
As excitement grows for the wealth of information we’ll receive on galaxies, it’s notable that my early interest skewed towards active galactic nuclei (AGNs)—galaxies boasting supermassive black holes that release immense energy as they consume matter near the event horizon. Admittedly, I was drawn to AGNs primarily for their black hole attributes.
During my PhD journey, my curriculum mandated multiple courses on galaxies, which initially overwhelmed me. Galaxies are classified by shape, each category diving into further sub-categories, revealing a perplexing web of classifications. This complexity often felt devoid of mathematical logic, highlighting a possible divide between theorists and experimentalists.
If only I could rewind time and tell my younger self that the challenges in galaxy classification were what deserved my attention.
One of the core challenges in this research realm is that galaxies only manifest as 2D images in the night sky; we lack the ability to perceive them in three dimensions or to observe their rotation due to their enormity. Thus, we rely on these frozen snapshots in time, interpreting their classification based on scientific judgment and taste.
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The shape of a galaxy offers fascinating insights into its evolutionary history – elliptical galaxies typically harbor older stars.
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Historically, Edwin Hubble devised a classification system for galaxies that remains influential today. He defined three fundamental shapes: elliptical, spiral, and irregular. Notably, lenticular galaxies, while appearing spiral, lack an actual spiral structure.
Gérard de Vaucouleurs expanded this classification by incorporating subcategories to identify patterns within galaxy shapes. However, the efficacy of these classifications hinges on the quality of the underlying dataset. A century ago, during Hubble’s time, the datasets were rudimentary, lacking knowledge of dark matter—a critical component now understood to inhabit galaxies.
Galaxy shapes serve as indicators of evolutionary history; for instance, elliptical galaxies often house older stars and lie closer in proximity to galaxy clusters. Furthermore, the assembly and evolution history of these galaxies relates intricately to the configuration of their surrounding dark matter halos.
Additionally, galaxy shapes can unveil secrets about dark energy, which accelerates the universe’s expansion. The Roman Space Telescope aims to deepen our understanding in this regard.
The Vera Rubin Observatory will extend its observational prowess, particularly focusing on dwarf spheroidal galaxies—dim, circular galaxies devoid of substantial star mass. These dwarf galaxies frequently accompany larger counterparts, helping to illuminate the evolutionary structure of the universe.
Excitingly, the scientific teams behind the Rubin and Roman telescopes are collaboratively strategizing on how best to utilize the forthcoming data. As we honor the legacies of Vera C. Rubin and Nancy Grace Roman, 2026 heralds a new generation dedicated to exploring galaxies in extraordinary detail.
What I’m currently reading:
Twilight novel series.
What I see:
Correct, the Twilight movie series.
What I’m working on:
I’m diligently finishing the draft of my third book: Cosmos is a Black Aesthetic.
Chanda Prescod-Weinstein is an associate professor of physics and astronomy at the University of New Hampshire. She is the author of Turbulent Universe and upcoming works The Ends of Space and Time: Particles, Poetry, and the Boogie of Cosmic Dreams.
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Source: www.newscientist.com
