hot big-bang model
Quick Summary
The hot big-bang model is the prevailing theory for the universe's evolution. It posits that the universe began 13.8 billion years ago from a state of extreme heat and density. This expansion caused a significant decrease in density and temperature, leading to the formation of hydrogen, helium, and lithium nuclei.1
Key assumptions of the model include the accuracy of Einstein's general theory of relativity and the cosmological principle, which states that the universe is uniform on large scales. About a million years after the big bang, atoms formed, allowing radiation to travel freely, creating the cosmic microwave background radiation detected today. While alternative theories have been proposed, the hot big-bang model remains dominant due to its ability to explain a wide range of cosmological observations.12
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- cosmologyThe hot big bang
Given the measured radiation temperature of 2.735 kelvins (K), the energy density of the cosmic microwave background can be shown to be about 1,000 times smaller than the average rest-energy density of ordinary matter in the universe. Thus, the current universe is…
Read MoreGiven the measured radiation temperature of 2.735 kelvins (K), the energy density of the cosmic microwave background can be shown to be about 1,000 times smaller than the average rest-energy density of ordinary matter in the universe. Thus, the current universe is…
Read More - cosmologySteady state theory and other alternative cosmologies
The hot big bang theory has ascended to primacy because, unlike its many rivals, it attempts to address not isolated individual facts but a whole panoply of cosmological issues. And, although some sought-after results remain elusive, no glaring weakness has yet been uncovered.
Read MoreThe hot big bang theory has ascended to primacy because, unlike its many rivals, it attempts to address not isolated individual facts but a whole panoply of cosmological issues. And, although some sought-after results remain elusive, no glaring weakness has yet been uncovered.
Read More