Index funds track major financial indexes, enabling broad market investment without picking individual stocks. Investing in index funds involves choosing an index, selecting a low-cost fund, and ...

Welcome to Smithsonian Open Access, where you can download, share, and reuse millions of the Smithsonian’s images—right now, without asking. With new platforms and tools, you have easier access to ...

Physics is the search for and application of rules that can help us understand and predict the world around us. Central to physics are ideas such as energy, mass, particles and waves. Physics attempts ...

Mar. 23, 2026 Scientists have uncovered a hidden “death switch” in the brain that may be driving Alzheimer’s disease—and even found a way to turn it off in mice. The culprit is a toxic pairing of two ...