Holiday kristall
Image: This box of holiday cheer is actually tubes of plasma containing suspended microparticles exposed to an electrical current to form 3D crystal structures.Called Plasma Kristall-4, this ESA–Roscosmos experiment has been helping to visualise atoms on the International Space Station to provide insights on basic physical processes. A plasma is an electrically charged gas, somewhat like lightning, that rarely occurs on Earth. It is considered to be the fourth state of matter, distinct from gas, liquids and solids.Plasma for the PK-4 experiment is created with neon or argon gas in tubes that make particles electrically charged. Scientists excite the particles with electrical fields, a laser and changes in temperature to get them to move them in the plasma.These manipulations cause the proxy atoms to interact strongly, leading to organised structures – plasma crystals. The plastic particles in PK-4 bond or repulse each other just as atoms do on Earth in fluid...