From those observations, the researchers assembled a two-step sequence of events:

• First, a supermassive black hole (a black hole with a mass of millions to billions of suns, sitting at the center of a galaxy) produced an outburst that injected enormous energy into its surroundings.
• Then, the two galaxy clusters collided, and that collision reshaped the black hole's outburst into the undulating figure observers see today.

In effect, the black hole supplied the material and the cluster collision supplied the deformation, the way a gust of wind turns a straight ribbon of smoke into a curling spiral.

Why does the shape matter?

Structures that emit radio waves, the kind traced here in pink, mark the presence of particles moving at close to the speed of light threaded through magnetic fields. When such particles occupy a disturbed environment, their geometry records the history of that disturbance. A shape as coherent as a treble clef therefore functions as a fossil of two violent events layered one on top of the other.

The finding also illustrates why astronomers combine instruments. The released image is a composite: X-ray data from Chandra, infrared data from UKIDSS-GPS (a survey mapping the sky in infrared light, beyond what human eyes perceive), and radio data from LOFAR, the Low Frequency Array operated by the Netherlands Institute for Radio Astronomy. NASA credits the image processing to N. Wolk of the Smithsonian Astrophysical Observatory, with the underlying X-ray analysis attributed to A. Botteon and collaborators at the Italian National Institute for Astrophysics' Institute of Radio Astronomy.

How confident should we be?

The proposed explanation, a black hole outburst followed by a cluster collision, is described by NASA as the likely cause rather than a settled conclusion. Detailed results on how the collision reworked the outburst into this particular geometry remain the subject of ongoing study, and NASA directs readers to a fuller account of the discovery on its science site.

That caution is standard practice. Pinning down the origin of extended radio structures requires matching their shapes, ages, and energy budgets against simulations of cluster mergers, and a single striking image cannot close that case on its own.

Still, the result stands as a tidy demonstration of how the largest structures in the universe can be shaped by events unfolding on vastly different scales: a black hole smaller than one solar system, and a collision spanning millions of light-years.

A treble clef tells a musician where the notes begin. This one tells astronomers where a black hole's outburst ended and a collision between galaxy clusters began.