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 pictures, 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 sudden — 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 Approach galaxy. That makes it longer than most identified stellar streams in our galaxy, that are principally just a few tens of hundreds of light-years in size.
The faint, galaxy-length breadcrumb path is assumed to encompass the leftovers of a dwarf galaxy that was torn aside by M61’s gravity. This breakup may additionally have been the catalyst for a starburst — an enormous enhance in new star formation — that started in M61 about 10 million years in the past.
The characteristic is harking back to the Sagittarius Stream — a protracted, looping construction that encircles the Milky Approach and whose stars originated within the Sagittarius Dwarf Elliptical Galaxy, scientists wrote in a examine 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 Approach, the Sagittarius Dwarf Elliptical Galaxy is assumed to have precipitated new spiral arms of stars to type throughout the Milky Approach. All of this means that the majority giant galaxies could 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 examine. “We anticipate 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 House and Time mission, throughout which it’s going to create a high-definition time-lapse report of the universe.
For extra elegant house pictures, take a look at our House Photograph of the Week archives.
