In recent experiments, scientists studied the size of the proton in hydrogen atoms. They used a vacuum chamber to carry out their work.
In 2010, researchers reported the proton’s radius as 0.84 femtometers. A femtometer is very small—it is one million-billionth of a meter. Later tests with heavy particles called muons confirmed this size. However, other studies gave different results.
For example, in 2018, another experiment showed a larger size. In 2019, scientists from York University measured the proton again and found it to be 0.833 femtometers. This matched the earlier 2010 result.
Now, two new studies have confirmed the proton’s size once more. They used lasers to control electrons and measured energy changes. These studies also show the proton is about 0.84 femtometers.
Experts say these results should be the same no matter how scientists measure the proton. This makes the new findings important because they support the original 2010 measurement.
