The Milky Way swallowed a smaller galaxy about 11.8 billion years ago
The Milky Way, a large and spiral-shaped galaxy that is home to hundreds of billions of stars including our sun, has taken a long and complicated path to achieve its current dimensions, as illustrated by new research documenting a milestone event early in its history. Scientists observing clusters of stars congregated near the Milky Way’s centre have discovered evidence that our galaxy swallowed…
Scientists have discovered that our Milky Way galaxy consumed a smaller galaxy, known as LKH, approximately 11.8 billion years ago. This merger was the earliest known galactic merger in the Milky Way's history and highlights the galaxy's growth through both star formation and galactic mergers. The smaller LKH galaxy, classified as a dwarf galaxy, contained stars with a mass around 500 million times that of the sun, making up roughly a quarter of the Milky Way's mass at the time of the merger.
Researchers utilized the Hubble and Gaia telescopes to examine stellar clusters within the Milky Way's innermost 20,000 light-years, analyzing their age, chemical composition, and trajectory. The LKH merger occurred about two billion years after the Big Bang, injecting a substantial amount of stars, interstellar gas, and dark matter into the Milky Way.
This merger is believed to have fed star formation and contributed to the formation of many stars still present in the Milky Way's inner regions. The Milky Way has experienced two other significant galactic mergers, including the Gaia-Sausage-Enceladus merger and the ongoing Sagittarius dwarf galaxy merger. These events have influenced various aspects of the Milky Way's evolution, including the formation of Earth and our solar system, making the reconstruction of the galaxy's past crucial to understanding our origins.
Written by urgent.news from South China Morning Post's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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