An international team of astronomers has made a unique measurement, confirming one of the postulates of the Big Bang theory. Researchers were able to determine the temperature of the Universe during a period when our planet had not even formed.

Scientists have analyzed light from a distant quasar that has traveled for 7 billion years. Researchers measured the temperature of the cosmic microwave background radiation, which is the faint afterglow of the Big Bang that permeates all space. Data from the ALMA telescope in Chile were used for precise measurements.

It turned out that The temperature of the Universe 7 billion years ago was 5.13 K (-268°C). This is almost double the modern value of 2.7 K (-270.45 °C). The measurement error was only 0.06 K, writes Science Alert.

“It’s like discovering cosmic “puddles” after a predicted “rain.” Each confirmation like this strengthens confidence in our cosmological model,” says lead author Tatsuya Kotani.

The light, passing through space, interacted with the cosmic microwave background radiation, leaving characteristic traces that allowed researchers to determine its temperature with unprecedented accuracy. This is the most accurate measurement ever obtained in the history of the Universe. There were previously measurements for the very early Universe and the present, but this fills an important middle chapter of the story.

The study not only confirms that the universe is indeed cooling as it expands, but also shows the power of modern astronomical instruments.