Hudson was Senior Wrangler and G. H. Hardy fourth wrangler.Jeans was elected Fellow of Trinity College in October 1901,[8][9] and taught at Cambridge, but went to Princeton University in 1904 as a professor of applied mathematics.

His analysis of rotating bodies led him to conclude that Pierre-Simon Laplace's theory that the solar system formed from a single cloud of gas was incorrect, proposing instead that the planets condensed from material drawn out of the sun by a hypothetical catastrophic near-collision with a passing star.

"[11] This theory fell out of favour when the 1965 discovery of the cosmic microwave background was widely interpreted as the tell-tale signature of the Big Bang.

These books made Jeans fairly well known as an expositor of the revolutionary scientific discoveries of his day, especially in relativity and physical cosmology.

In 1939, the Journal of the British Astronomical Association reported that Jeans was going to stand as a candidate for parliament for the Cambridge University constituency.

Jeans also helped to discover the Rayleigh–Jeans law, which relates the energy density of black-body radiation to the temperature of the emission source.

Jeans espoused a philosophy of science rooted in the metaphysical doctrine of idealism and opposed to materialism in his speaking engagements and books.

"[21] When Daniel Helsing reviewed The Mysterious Universe for Physics Today in 2020, he summarized the philosophical conclusions of the book, "Jeans argues that we must give up science's long-cherished materialistic and mechanical worldview, which posits that nature operates like a machine and consists solely of material particles interacting with each other."

"[18] The Astronmical Horizon https://www.amazon.co.uk/dp/B000NIS57O?ref=myi_title_dp- The Philip Maurice Deneke Lecture 1944 - Published Oxford University Press 1945