50 years ago, physicists got a whiff of what glues together protons
Excerpt from the September 16, 1972 issue of Science News
![an illustration of the internal structure of a proton](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2022/09/081222_mt_50ya-gluons_feat.jpg?fit=1030%2C580&ssl=1)
In this illustration of a proton’s internal structure, quarks (represented by the letters U and D) are held together by the strong nuclear force (helices), which is imparted by particles called gluons.
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