Enlarge / Computer artwork of the nucleus of a helium atom, or an alpha particle given off during radioactive decay. The nucleus consists of two positively charged protons (red) and two neutral neutrons (green) surrounded by a quantum cloud of gluons, a type of subatomic particle. In recent months, I’ve mentioned super-solids a couple of times, which is a bit unusual for something we haven't been
![Super-solid helium state confirmed in beautiful experiment | Ars Technica](https://cdn-ak-scissors.b.st-hatena.com/image/square/04d1a07149b2d3a773b462bc09225fb8c8f06a6e/height=288;version=1;width=512/https%3A%2F%2Fcdn.arstechnica.net%2Fwp-content%2Fuploads%2F2018%2F12%2Fhelium-atom-760x380.jpg)