Astronomers spot ‘cosmic joust’ for first time as two galaxies collide

By Dean Murray

Jaw-dropping scenes show two galaxies having a "cosmic joust."

Astronomers have witnessed for the first time a violent space collision in which one galaxy pierces another with intense radiation.

Their results, published in Nature, show that this radiation dampens the wounded galaxy’s ability to form new stars.

The new study combined observations from both the European Southern Observatory’s (ESO) Very Large Telescope (ESO’s VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA), which ESO says reveals "all the gory details of this galactic battle."

ESO said: "In the distant depths of the Universe, two galaxies are locked in a thrilling war. Over and over, they charge towards each other at speeds of 500 km/s on a violent collision course, only to land a glancing blow before retreating and winding up for another round."

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Study co-lead Pasquier Noterdaeme commented: "We hence call this system the "cosmic joust."

ESO add: "But these galactic knights aren’t exactly chivalrous, and one has a very unfair advantage: it uses a quasar to pierce its opponent with a spear of radiation."

Quasars are the bright cores of some distant galaxies that are powered by supermassive black holes, releasing huge amounts of radiation.

The light from this "cosmic joust" has taken over 11 billion years to reach us, so we see it as it was when the Universe was only 18% of its current age.

The research team included members from Ioffe Institute, Institut d’Astrophysique de Paris, French-Chilean Laboratory for Astronomy, Inter-University Centre for Astronomy, Université Lyon I, Collège de France, and Universidad de Chile.