The Universe’s brightest lights born from darkness

By Pranjal Malewar 5 May, 2025

Collected at: https://www.techexplorist.com/universe-brightest-lights-born-darkness/99295/

Would you believe if someone told you that some of the most brilliant beacons in the cosmos come from the chaotic neighborhoods around black holes? It might sound paradoxical—how can something known for swallowing everything, even light, become a source of dazzling illumination?

Yet, this is precisely what astronomers have uncovered about active galactic nuclei (AGN), the blazing hearts of certain galaxies powered by supermassive black holes.

Supermassive black holes lurk at the centers of most galaxies, wielding gravitational forces so intense that nothing—not light, matter, or even curiosity—can escape their grasp. But when vast quantities of gas and dust spiral toward a black hole, they don’t just vanish instantly.

Instead, they form a swirling accretion disk, heating up due to extreme friction and gravitational forces. This process unleashes enormous amounts of energy across the electromagnetic spectrum, transforming these galactic cores into some of the Universe’s brightest objects.

NASA’s Fermi Gamma-ray Space Telescope has been scanning the heavens since 2008, uncovering thousands of radiant galactic cores. The telescope detects gamma rays—the most energetic form of light—that stream from AGN as matter accelerates and interacts with powerful magnetic fields.

More than half of Fermi’s discoveries have been blazars, a specific type of AGN whose jets of particles are pointed almost directly toward Earth. This alignment makes blazars appear especially bright, earning them a top spot on astronomers’ cosmic watchlist.

Some AGN take their energy spectacle even further by ejecting high-speed jets of particles, traveling nearly at the speed of light. How black holes, notorious for their gravitational pull, manage to propel such powerful streams outward remains an open question—one scientists are racing to solve.

These energetic jets play a crucial role in shaping their surroundings, influencing star formation and galactic evolution on a cosmic scale. Some AGN formed in the early Universe, meaning their incredible power likely helped sculpt galaxies into the structures we observe today.

Beyond their mesmerizing light shows, AGN offers key insights into our Universe’s past and future. By studying these cosmic engines, scientists piece together the story of galactic formation, the interplay of gravitational forces, and the mechanics behind extreme particle acceleration.