In 1956, Joseph Shklovsky theorized that a supernova caused the dinosaurs' extinction. In the 1970s, Walter Alvarez discovered a thin layer of clay, known as the KT boundary, which marked a mass extinction event. With help from his father Luis Alvarez and chemist Frank Asaro, they found high levels of iridium in the clay, suggesting a global impact event. Initially ridiculed, their asteroid impact theory gained credibility after Alan Hildebrand identified the Chicxulub crater in Mexico in 1990. The 1994 impact of comet Shoemaker-Levy 9 on Jupiter demonstrated the potential for such catastrophic events, supporting the Alvarez hypothesis. This summary is based on information from various sources, notably Bill Bryson.

The anecdote about British astronomer Sir Arthur Eddington humorously highlights the complexity of Einstein’s relativity theories. When asked if he was one of only three people who understood relativity, Eddington quipped he couldn't think of the third person, underscoring the nonintuitive nature of the theory. Relativity fundamentally posits that space and time are not absolute but relative to the observer and the object being observed, with effects becoming more pronounced at higher speeds. To illustrate this, Bertrand Russell in his book "The ABC of Relativity" used the analogy of a train moving at 60% of the speed of light. To an observer on a platform, the train would appear shorter, the passengers' voices slower, and their movements and clocks significantly slower. This analogy helps make the abstract concepts of relativity more accessible to the general public.