>> The new measurement puts the size of the proton to around 0.833 femtometers, against the previously accepted figure of 0.842 femtometers.<p>1 femtometer = 10^−15 metres. Also commonly called a fermi.<p>It's a quick read, worth the click to read how they measured it, and at least see CERN's imagined rendition of what the "turmoil of quarks and gluons" that make up a proton might look like.
I find this somewhat baffling. 4% just seems like such a huge disparity, especially for such a ubiquitous particle. It seems like any experiments before 2010, that used the size of a proton in the calculations should have noticed something was wrong. Fermilab has spent the last couple years trying spruce up an old experiment to measure the dipole-moment of the muon down to 0.14 ppm[1][2] Apparently that small of a discrepancy in theory and experiment was interesting enough to throw a huge amount of time into. How is it that we are trying to verify the 9th significant digit in the dipole moment of an obscure particle, while something as mundane as the size of the proton was off by 4%? Obviously, I'm missing something.<p>[1]<a href="https://en.wikipedia.org/wiki/Muon_g-2" rel="nofollow">https://en.wikipedia.org/wiki/Muon_g-2</a><p>[2]<a href="https://www.youtube.com/watch?v=UckuqHDB08I" rel="nofollow">https://www.youtube.com/watch?v=UckuqHDB08I</a>
>When a hydrogen atom is in its lower energy state, the electron not only orbits around the proton, but rather stays inside it.<p>This is the first time I have ever learned this is possible in all my years of schooling and working in science. Fascinating, this article changed how I think about the universe.
Another article that fails to mention two out of three accurate measurements done on regular hydrogen since 2010. The news article about the most recent measurement gets it right: <a href="https://news.yorku.ca/2019/09/05/scientists-measure-precise-proton-radius-to-help-resolve-decade-old-puzzle/" rel="nofollow">https://news.yorku.ca/2019/09/05/scientists-measure-precise-...</a>
Physicists have "observed quarks" for a long time in the sense that if you scatter protons against protons or other particles, you can see that the proton scatters particles as if it was made up of three little particles.
Not a physics guy, so my understanding is probably wrong. Aren't all particles infinite in size and are just blips in the fields behind our universe?
A neutron star is so dense that a matchbox sized portion of one would weigh 3 billion tons.<p><a href="https://clearlyexplained.com/neutron-stars/index.html" rel="nofollow">https://clearlyexplained.com/neutron-stars/index.html</a>