From Copernicus to Einstein, the field of Physics has changed drastically over time. With each new theory, further hypotheses appear that challenge conventional wisdom. Today, although topics such as the Big Bang Theory and General Relativity are well-established, there are still some debates that keep physicists up at night. What are your thoughts on the five of the biggest current debates in Physics?
With the emergence of a new picture of our expanding universe in the 1960s, the nature of dark energy became a top priority in fundamental physics. Another and related priority, of a somewhat older age, was to understand the nature of the dark matter that was known to dominate over the ordinary matter in a ratio of about 5:1. Already, around 1990, it was agreed that the major part of the mysterious dark matter was ‘cold’, meaning that it is made up of relatively slowly-moving particles unknown to experimenters but predicted by physical theory. The particles of cold dark matter (CDM) were collectively known as WIMPs—‘weakly interacting massive particles’. Several such hypothetical particles have been suggested as candidates for the exotic dark matter, and some are more popular than others, but the nature of the dark-matter component remains unknown.