The Milky Way’s Oldest Stars Are Moving in Unexpected Ways – ScienceAlert

Some of the Milky Way’s oldest stars aren’t where we expect them to be.
One of the ways we categorize stars is by their metallicity. That is the fraction of heavier elements a star has compared to hydrogen and helium. It’s a useful metric because the metallicity of a star is a good measure of its age.
The hydrogen and helium we see in the Universe were created in the early moments of the Big Bang. That’s why they are so plentiful. Heavier elements such as carbon and iron are created through astrophysical…

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