‘Galactic heartbeat detected’: Hubble captures ancient clusters colliding in real time
Produced by: Manoj Kumar
Galactic Building Blocks
Dwarf galaxies, small yet mighty, are the most common galaxies in the universe—and crucial to understanding the growth of cosmic giants.
Core Densities
Many dwarf galaxies hide ultra-dense nuclear star clusters at their centers, housing up to millions of stars in a compact, glowing core.
Long-Theorized, Now Seen
For decades, scientists believed these nuclear clusters formed from globular cluster mergers. Now, we finally have the first direct proof.
Cosmic Cannibalism
Using Hubble data, astronomers spotted tightly paired clusters and light streams—hallmarks of one cluster being absorbed by another.
Stream Signals
Some galaxies had ghostly streaks of light near their centers. These ephemeral trails are the telltale signatures of a merger in motion.
A Rapid Dance
The entire merging process takes less than 100 million years. The light streams fade even faster—making this a rare catch.
Super Simulations
Ultra-detailed computer models reproduced the phenomenon, confirming that the observed streams result from unequal-mass cluster mergers.
Massive Clue
The simulations showed: the bigger the size difference between the two clusters, the longer and clearer the light stream becomes.
Star-Crushing Impact
Led by Mélina Poulain and supported by the MATLAS team, this discovery deepens our understanding of how galaxies evolve and grow from within.