Hubble Reveals Ancient LKH Collision Shaped the Milky Way's Growth

The Milky Way was much smaller when it was young.

About 11.8 billion years ago, it swallowed a smaller galaxy called LKH.

That event helped add stars, gas, and dark matter to the growing Milky Way.

Scientists studied 39 very old groups of stars called globular clusters.

Hubble helped measure their ages and the amounts of heavy elements they contained.

Data from the Gaia mission helped scientists sort the clusters into different groups.

One group came from LKH, while another came from a different merger about 10 billion years ago.

The discovery shows that some of the Milky Way’s earliest stars came from other galaxies.