Description:
This massive globular cluster, 47 Tucana, 14,000 light years away, 1 million stars within, is in our galaxy.
On the left is NGC121 and on the right is Kron3, both 10 times further, in the Small Magellanic Cloud, a nearby dwarf galaxy that orbits the Milky Way.
NGC 121 formed very early in the universe, while Kron 3 formed several billion years later. Comparing them inside the same dwarf galaxy cleanly traces how star formation and cluster building changed over cosmic time without the confounding differences between galaxies.
NGC 121 and Kron 3 together act like “bookends” of the SMC’s cluster history, letting us test how galaxies enrich, interact, and build long-lived star clusters across much of cosmic time.