QUICK FACTS
What it’s: Barred spiral galaxy Messier 61, AKA NGC 4303
The place it’s: 55 million light-years away within the constellation Virgo
When it was shared: Oct. 28, 2025
Even earlier than its full science operations have begun, the Vera C. Rubin Observatory in Chile has already helped astronomers discover one thing outstanding. The observatory’s first photos, revealed in June, contained a deep view of the Virgo cluster, the closest and best-studied cluster of galaxies. And within the bottom-right of the picture, eagle-eyed astronomers noticed one thing surprising — a razor-thin stream of stars arcing away from one of many cluster’s galaxies.
The stream stretches roughly 50 kiloparsecs (about 163,000 light-years), which is similar to the diameter of our Milky Method galaxy. That makes it longer than most recognized stellar streams in our galaxy, that are principally only some tens of 1000’s of light-years in size.
The faint, galaxy-length breadcrumb path is believed to encompass the leftovers of a dwarf galaxy that was torn aside by M61’s gravity. This breakup may have been the catalyst for a starburst — an enormous improve in new star formation — that started in M61 about 10 million years in the past.
The characteristic is paying homage to the Sagittarius Stream — a protracted, looping construction that encircles the Milky Method and whose stars originated within the Sagittarius Dwarf Elliptical Galaxy, scientists wrote in a research uploaded Oct. 28 to the pre-print server arXiv, which is because of be printed within the journal Notes of the American Astronomical Society.
A satellite tv for pc galaxy of the Milky Method, the Sagittarius Dwarf Elliptical Galaxy is believed to have precipitated new spiral arms of stars to type throughout the Milky Method. All of this means that the majority massive galaxies might type by consuming different, smaller galaxies round them.
“It’s outstanding that the stream went lengthy unnoticed round a Messier galaxy,” the authors wrote within the research. “We count on a treasure trove of substructures to be unveiled round different galaxies with future Rubin knowledge.”
Rubin is about to embark on its 10-year Legacy Survey of Area and Time mission, throughout which it can create a high-definition time-lapse report of the universe.
For extra chic house photos, take a look at our Area Picture of the Week archives.
