Assignment 40

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Astronomy

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Oct 30, 2023

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Academic rigour, journalistic ﬂair Rajendra Gupta Adjunct professor, Physics, L’Université d’Ottawa/University of Ottawa Languages Español English Early universe observations by the James Webb Space Telescope (JWST) cannot be explained by current cosmological models. These models estimate the universe to be 13.8 billion years in age, based on the big-bang expanding universe concept. My research proposes a model that determines the universe’s age to be 26.7 billion years, which accounts for the JWST’s “impossible early galaxy” observations. Galaxy NGC 6822, neighbouring the Milky Way galaxy, being studied to learn more about stars and dust in the early universe. (NASA/James Webb Space Telescope) How old is the universe exactly? A new theory suggests that it’s been around for twice as long as believed Published: August 28, 2023 12.53pm EDT   Listen to this article Great journalism deserves to be heard

Impossible early galaxies refer to the fact that some galaxies dating to the cosmic dawn — 500 to 800 million years after the big bang — have discs and bulges similar to those which have passed through a long period of evolution. And smaller in size galaxies are apparently more massive than larger ones, which is quite the opposite of expectation. Frequency and distance This age estimate is derived from the universe’s expansion rate by measuring the redshift of spectral lines in the light emitted by distant galaxies. An earlier explanation of the redshift was based on the hypothesis that light loses energy as it travels cosmic distances. This “tired light” explanation was rejected as it could not explain many observations. The redshift of light is similar to the Doppler effect on sound: noises appear to have higher frequency (pitch) when approaching, and lower when receding. Redshift, a lower light frequency, indicates when an object is receding from us; the larger the galaxy distance, the higher the recessional speed and redshift. An alternative explanation for the redshift was due to the Doppler effect: distant galaxies are receding from us at speeds proportional to their distance, indicating that the universe is expanding. The expanding universe model became favoured by most astronomers after two astronomers working for Bell Labs, Arno Penzias and Robert Wilson, accidentally discovered cosmic microwave background (CMB) radiation in 1964, which the steady-state model could not satisfactorily explain. A NASA animation showing how light from distant galaxies is stretched by the expansion of the universe.

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