A recent study led by a team of researchers from Keio University has revealed that the Universe was significantly hotter seven billion years ago, approximately double its current temperature. This finding offers compelling support for the Big Bang theory, which posits that the Universe cools as it expands.
Guided by doctoral student Tatsuya Kotani and Professor Tomoharu Oka, the research team conducted a meticulous analysis of the cosmic microwave background radiation, the residual energy from the Big Bang that fills the cosmos. Unlike contemporary measurements, the researchers focused on light that had journeyed through space for seven billion years, allowing them to assess the temperature of the Universe during that era.
Their analysis revealed a temperature of 5.13 degrees Kelvin above absolute zero, with a margin of error of ±0.06 K. This measurement is notably about twice the current temperature of 2.7 K. Such precision is vital, as it tests the foundational predictions of cosmological evolution.
Employing data from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the team examined light emitted by a distant quasar. As this light traversed the Universe, it interacted with the cosmic background radiation, producing distinctive signatures that enabled the researchers to ascertain its temperature with unprecedented accuracy. This marks the most precise temperature measurement captured at this intermediate epoch of the Universe”s timeline.
Previous studies had successfully measured temperatures from both the early Universe and the present day, but this study fills a critical gap in our understanding of cosmic history. The findings reinforce the framework of the standard model of cosmology, which provides specific, testable predictions regarding the behavior of the Universe.
Just as a weather forecast gains credibility when observed conditions align with predictions, the confirmation of the expected temperature for the Universe seven billion years ago enhances trust in our cosmological models. This research not only emphasizes the cooling trend of the Universe but also strengthens our grasp of its evolutionary journey.
This article originally appeared on Universe Today.
