First-ever cosmic duel caught: One galaxy blasted another in deep space battle 11 billion light-years away

Astronomers have, for the first time, captured a dramatic cosmic event: two galaxies engaged in a high-speed collision, aptly dubbed a "cosmic joust." This celestial spectacle, occurring over 11 billion light-years away, offers unprecedented insights into galaxy evolution and the influence of quasars on star formation.

A clash of titans

Utilizing the combined capabilities of the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Southern Observatory's Very Large Telescope (VLT) in Chile, researchers observed two massive galaxies hurtling toward each other at approximately 1.1 million miles per hour (1.8 million kilometers per hour). One of these galaxies harbors a quasar—a luminous, energetic core powered by a supermassive black hole—emitting intense radiation that pierces its galactic neighbor.


"Much like jousting knights charging toward one another, these galaxies are rapidly approaching," explained Pasquier Noterdaeme, co-lead of the study and researcher at the Paris Institute of Astrophysics and the French-Chilean Laboratory for Astronomy in Chile. "One of them—the quasar host—emits a powerful beam of radiation that pierces the companion galaxy, like a lance. This radiation 'wounds' its 'opponent' as it disrupts the gas."

Star formation

The quasar's ultraviolet radiation, about a thousand times stronger than that of our Milky Way, disrupts the molecular gas clouds in the companion galaxy. These clouds, typically the birthplaces of stars, are fragmented into tiny, dense cloudlets too small to initiate star formation.

"It's really the first time that we can see the radiative effect of a quasar on the molecular gas of a nearby galaxy," noted Sergei Balashev, co-author of the study and researcher at the Ioffe Institute in St. Petersburg, Russia. "Until now, this effect had only been theorized but not confirmed through direct observation."

This cosmic encounter occurred when the universe was merely 2.4 billion years old, providing a rare window into the early stages of galaxy formation and interaction. The galaxies involved are similar in size to the Milky Way, each containing hundreds of billions of stars.

"Galaxies are typically found in groups, and gravitational ...," Noterdaeme said. "In line with current understanding, these ... The quasar will fade as it."

Implications for galactic evolution

The observation not only confirms long-standing theories about quasar influence on star formation but also underscores the dynamic and often violent nature of galaxy evolution. As galaxies merge, the influx of gas can fuel supermassive black holes, triggering quasar activity that, in turn, can suppress star formation in neighboring regions.

"This study provides the first direct evidence supporting long-standing theoretical models," said Neeraj Gupta, a researcher at the Inter-University Centre for Astronomy and Astrophysics (IUCAA) in Pune, India, who contributed to the research.

What’s next

While the light from this event has taken over 11 billion years to reach us, the implications of this discovery are immediate, offering a deeper understanding of the complex interplay between galaxies and the forces that shape them. As astronomers continue to explore the cosmos, observations like this "cosmic joust" illuminate the intricate dance of creation and destruction that governs our universe.