window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'UA-41134143-1');

The Big Bang 3: Lemaître’s universe, Hubble’s law

Georges Lemaître was a devout priest and a brilliant physicist who found Hubble’s Law in theory two years before Hubble did in practice. He took Einstein’s equations of general relativity and showed that they had a solution in which the universe expands, with the speed of expansion increasing as time goes on – just as Hubble had observed in his study of distance and speed of recession of the spiral nebulae. Born in 1894 in Charleroi in Belgium, Lemaître was educated at a Jesuit school and went to university to study civil engineering. World War I

The Big Bang 2: A shift in the mist

The Latin word nebula means ‘mist’, and originally a nebula was any sort of misty patch in the sky. Today it is more precise, referring to an interstellar cloud of dust and gas; and we shall see in a moment why the name evolved. An issue that came to the fore around 1920 was the question of the nature of a particular group of nebulae – spiral nebulae. It was know that a number of these spiral nebulae were moving away from us, at a significant speed. It was possible to find this out by using

The Big Bang 1: The first ideas

The story of the development of the idea of the Big Bang has two separate strands, and we have to switch back and fore between them. The one strand is the observational work of astronomers, developing techniques to measure the distance of stars and galaxies – and also their relative speed. The discovery – published by Edwin Hubble in 1929 – that the galaxies are receding from us, with the speed of recession growing with distance, is the basis of the belief of an expanding universe. A parallel strand of investigation involves purely pencil and paper,

Go to Top