A staggering galaxy collision, initiated by one moving at an astonishing speed of 2 million mph (3.2 million km/h), has been captured in remarkable detail by one of the most advanced telescopes on Earth. This spectacular event occurred in Stephan’s Quintet, a nearby group of five galaxies that was first discovered almost 150 years ago. The collision produced an extremely powerful shock, reminiscent of a “sonic boom from a jet fighter,” showcasing some of the most impressive phenomena witnessed in the universe.
A staggering galaxy collision, initiated by one moving at an astonishing speed of 2 million mph (3.2 million km/h), has been captured in remarkable detail by one of the most advanced telescopes on Earth.
This spectacular event occurred in Stephan’s Quintet, a nearby group of five galaxies that was first discovered almost 150 years ago.
The impact created a shock wave that was extremely powerful, akin to a “sonic boom from a jet fighter” — a phenomenon among the most breathtaking in the universe.
Stephan’s Quintet serves as “a galactic intersection where earlier collisions between galaxies have resulted in a tangled field of debris,” now re-energized by the movement of the galaxy NGC 7318b.
The collision was detected by a team of researchers using the initial observations from the newly established 20-million Euro (£16.7 million) William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE) wide-field spectrograph in La Palma, Spain.
This innovative science facility is set to not only shed light on how our Milky Way galaxy has developed over billions of years but also provide new insights into millions of other galaxies in the universe.
The finding of NGC 7318b crashing through Stephan’s Quintet was made by a coalition of over 60 astronomers, with the results published today in Monthly Notices of the Royal Astronomical Society.
The system serves as an excellent venue to comprehend the turbulent and often violent dynamics between galaxies, which is why it was a prime candidate for the first-light observation by the WEAVE Large Integral Field Unit (LIFU).
Lead researcher Dr. Marina Arnaudova from the University of Hertfordshire expressed, “Since its discovery in 1877, Stephan’s Quintet has fascinated astronomers, as it represents a galactic intersection where prior collisions between galaxies have left behind a complex field of debris.”
“The dynamic activity within this galaxy group has now been reinvigorated by a galaxy moving at an incredible speed of over 2 million mph (3.2 million km/h), resulting in a shock wave that resembles a sonic boom from a jet fighter.”
The international team has uncovered a previously unknown dual nature of the shock front.
“As the shock traverses cold gas pockets, it travels at hypersonic speeds — several times the sound speed in the intergalactic medium of Stephan’s Quintet* — powerful enough to disintegrate electrons from atoms, creating a luminous trail of charged gas, as observed with WEAVE,” Dr. Arnaudova explained.
However, when the shock waves encounter the surrounding hot gas, they weaken significantly, according to PhD student Soumyadeep Das from the University of Hertfordshire.
He added, “Rather than causing major disruptions, the diminished shock compresses the hot gas, producing radio waves detected by radio telescopes such as the Low Frequency Array (LOFAR).”
The novel insights and details were made possible through WEAVE’s LIFU, which combined data with other advanced instruments like the LOFAR, the Very Large Array (VLA), and the James Webb Space Telescope (JWST).
WEAVE acts as a sophisticated, ultra-fast mapping device attached to the William Herschel Telescope, which analyzes the composition of stars and gas in both our Milky Way and distant galaxies.
It uses a spectroscope that reveals the elements within stars by generating a barcode-like pattern in a spectrum of colors from a light source.
This project was developed and constructed through a multi-national agreement by France, Italy, and the countries involved in the Isaac Newton Group of Telescopes (including the UK, Spain, and the Netherlands).
Astronomers anticipate that WEAVE will unveil how our galaxy formed in unprecedented detail, transforming our understanding of the universe.
Dr. Daniel Smith from the University of Hertfordshire remarked, “It’s impressive work that Marina and her extensive team have accomplished. This first WEAVE science publication is merely a glimpse of the exciting discoveries to come over the next five years now that WEAVE is becoming fully operational.”
Professor Gavin Dalton, principal investigator of WEAVE at RAL Space and the University of Oxford, noted, “It’s amazing to witness the depth of detail uncovered by WEAVE.
“Besides the details of the shock and the ongoing collision in Stephan’s Quintet, these observations provide a remarkable view of potential activities occurring in the formation and evolution of faint galaxies that lie at the edge of our observational capabilities.”
Dr. Marc Balcells, director of the Isaac Newton Group of Telescopes, expressed his excitement, stating, “I’m thrilled to see that data collected during WEAVE’s first light has already yielded significant results — and I am confident this is just an early instance of the discoveries WEAVE will facilitate on the William Herschel Telescope in the coming years.”
C-UKRI) of the United Kingdom, the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands, and the IAC in Spain. IAC’s contribution to the ING is funded by the Spanish Ministry of Science, Innovation and Universities.
