The Milky Way Has Been Growing by Consuming Smaller Galaxies.
The Milky Way Has Been Growing by Consuming Smaller Galaxies.
By absorbing smaller
galaxies over billions of years, the Milky Way has grown. The Milky Way's
gravity has the ability to tear apart a dwarf galaxy if it comes too close,
scattering its stars into long streams and clouds around our galaxy. 🔠Astronomers can identify these ancient mergers
because the stolen stars retain unusual motions and chemical signatures. Their routes may indicate that they came from
somewhere other than the Milky Way. Gaia-Enceladus, a dwarf galaxy that merged
with the young Milky Way about 8–10 billion years ago, is one of the most
significant examples. Its remnants now make up a significant population of
stars in the Milky Way’s stellar halo.
The process continues to this day. The Sagittarius dwarf spheroidal galaxy is currently
being disrupted by the Milky Way, leaving enormous streams of stars wrapped
around our galaxy.
✨ Some of the stars we see in the Milky Way may have been born
in galaxies that no longer exist. The
Milky Way’s history is, in part, a history of
cosmic mergers.

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