Title: The history of the universe: an exergetic study

Authors: Birol Kılkış

Addresses: OSTIM Technical University, Ostim, 100. Yıl Blv. 55/F, 06374 Yenimahalle/Ankara, Türkiye

Abstract: The cosmic age has been calculated as 13.819 Gyr, using the second law of thermodynamics to predict a twin universe, and confirms the literature's age of 13.787 Gyr. The first exergy-based research addressing the cosmic age, published in this journal in 2004 and 2014, predicted a cosmic age of 14.885 Gyr. This paper resolves the age discrepancy by postulating a second epoch spanning between 14.885 Gyr and 13.819 Gyr, which connects the universe twins as a transition and transformation of the observable universe into its twin, following the same time arrow.

Keywords: cosmic age; exergy flow; twin universe; radiating universe model; second law of thermodynamics.

DOI: 10.1504/IJEX.2026.151389

International Journal of Exergy, 2026 Vol.49 No.1, pp.33 - 44

Received: 06 Apr 2025
Accepted: 10 Jul 2025
Published online: 26 Jan 2026 *

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