Hidden in Plain Sight 7: The Fine-Tuned Universe (Volume 7) by Dr. Andrew H. Thomas

Author:Dr. Andrew H. Thomas [Thomas, Andrew H.]
Language: eng
Format: epub
ISBN: 9781542749671
Amazon: 1542749670
Publisher: CreateSpace Independent Publishing Platform
Published: 2017-01-24T00:00:00+00:00

The priest

Georges Lemaître was a Belgian physicist who is now regarded as one of the most important physicists and cosmologists of the 20th century. Surprisingly, however, Lemaître was not a physicist by profession. Instead, in 1923, he was ordained as a Roman Catholic priest and remained in the priesthood for his entire life.

Lemaître always managed to keep a distance between his personal beliefs and his scientific research, even once arguing with the Pope over the Pope's interpretation of Lemaître's own Big Bang theory. That disagreement did not stop Lemaître from eventually becoming the president of the Pontifical Academy of Sciences.

In 1924, Lemaître realised that Einstein's cosmological constant would not be sufficient to produce a stable universe. Like a pencil balancing on a point, the apparently stable universe would actually be unstable. Even the slightest variation between the amount of matter in the universe and the value of the cosmological constant would result in a universe which either contracted to a point or expanded forever. A pencil cannot stay balanced on its point forever.

Lemaître's 1924 paper also predicted that if the universe really was expanding then the expansion could be measured by astronomical observations. Light from receding galaxies would be shifted towards the red end (longer wavelength) of their spectrum because of the Doppler effect. Lemaître realised that general relativity predicted a linear relationship between the distance of faraway galaxies and their redshift.

In 1927, the American astronomer Edwin Hubble decided to check this predicted relationship between distance and velocity. Hubble calculated the distance of galaxies by measuring their brightness, and relied on his assistant — Milton Humason — to measure the spectra of the galaxies.

By January 1929, Hubble and Humason had distance and spectra data for twenty-four distant galaxies. Hubble plotted the data on a graph, with distance on the x axis and velocity (calculated from the redshifts) on the y axis. The scatter of points lay close to a straight line, indicating a linear relationship between distance and recession velocity — just as Lemaître had predicted.

The following image shows Hubble's actual graph from his 1929 paper (which never credited the work of Humason) in the Proceedings of the National Academy of Sciences:

When he read about Hubble's discovery, Einstein realised his blunder in horror. An expanding universe had no need of a cosmological constant to keep it static. Einstein realised he could have predicted the expanding universe from general relativity before Hubble discovered it from observation. Einstein was later to call his introduction of the cosmological constant the "biggest blunder" of his life.

Einstein had lost the initiative and the leadership. From now on, for the rest of his career, Einstein was always playing catch-up in physics.

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