Trump’s cuts to NASA and the National Science Foundation will have huge consequences
Artemis I sits at Launch Pad 39-B at Kennedy Space Center Tribune Content Agency LLC/Alamy The Stern-Gerlach experiment is, in my opinion, truly the first test that forced the results of quantum mechanics onto the scientific community. Proposed by Otto Stern and conducted by Walther Gerlach in 1922, it showed that atoms have a quantum structure. Electrons, it turned out, must follow quantum rules. The Stern-Gerlach experiment also highlights a weird feature of the quantum world: it seems that the observer can determine the possible properties a particle can have. If I measure a quantum property known as spin, the fact the measurement happened seems to change the possible values of spin a particle can have later. In other words, whether a particle was observed or not determines its future. In physics, we are socialised to the idea that we are outside of the physical system, watching it. In this experiment, suddenly we aren’t. In my experience, students initially absorb this as a fact they must accept. Only after being forced to think about it …