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Milky Way Disc Ends at 40,000 Light-Years, Study Finds

4/29/2026

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Summary

Story summary

Astronomers led by Karl Fiteni announced the Milky Way’s disc ends at 40,000 light-years, the limit of its star-forming region.
The team measured ages of 100,000 giant stars using LAMOST, APOGEE and Gaia.
They found an age dip at 40,000 light-years, with younger stars there and older stars elsewhere.
The Milky Way is a Type-II down-bending disc, a pattern seen in about 60 % of galaxies.

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Story summary

Astronomers led by Karl Fiteni announced the Milky Way’s disc ends at 40,000 light-years, the limit of its star-forming region.
The team measured ages of 100,000 giant stars using LAMOST, APOGEE and Gaia.
They found an age dip at 40,000 light-years, with younger stars there and older stars elsewhere.
The Milky Way is a Type-II down-bending disc, a pattern seen in about 60 % of galaxies.