5 twinkling galaxies help us uncover the mystery of the Milky Way’s missing matter – Phys.org

We’ve all looked up at night and admired the brightly shining stars. Beyond making a gorgeous spectacle, measuring that light helps us learn about matter in our galaxy, the Milky Way.
When astronomers add up all the ordinary matter detectable around us (such as in galaxies, stars and planets), they find only half the amount expected to exist, based on predictions. This normal matter is “baryonic”, which means it’s made up of baryon particles such as protons and neutrons.
But about half of this matter…

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