Temperature of the Universe is going down as predicted by the Big Bang theory

CSIRO’s Australia Telescope Compact Array (Credit: David Smyth)

Astronomers have taken the temperature of the Universe and reported that the temperature cooled down as predicted by the Big Bang theory.

This research has been accepted for publication in the journal Astronomy & Astrophysics.

Astronomers measured the temperature of the universe, when it was half of its current age, with the help of CSIRO Australia Telescope Compact Array near Narrabri, NSW.

Changes in the radio waves from the background shows the temperature of the gas (Credit: Onsala Space Observatory)

In order to study the temperature, astronomers studied the gas in an unnamed galaxy 7.2 billion light-years away [a redshift of 0.89 (z=0.89)]. This gas has been warmed by the cosmic background radiation i.e. the shine remained from the Big Bang. There is another galaxy, a quasar (referred to as PKS 1830-211), present behind the unnamed galaxy. As the radio waves from this quasar move through the galaxy, the gas molecules absorb some of the energy of the radio waves leaving a distinctive “fingerprint” on the radio waves. These, so-called fingerprints, could be used to determine the gas’s temperature that has been found to be 5.08 Kelvin (-268.07 degrees Celsius). Although, it is extremely cold temperature but still it is warmer than today’s Universe that is at 2.73 Kelvin (-270.42 degrees Celsius).

“This is the most precise measurement ever made of how the Universe has cooled down during its 13.77 billion year history,” Dr Robert Braun, Chief Scientist at CSIRO Astronomy and Space Science, said in a statement.

Big Bang theory shows that the temperature of the cosmic background radiation falls smoothly with the expansion of the Universe. “That’s just what we see in our measurements. The Universe of a few billion years ago was a few degrees warmer than it is now, exactly as the Big Bang Theory predicts,” said research team leader Dr Sebastien Muller of Onsala Space Observatory at Chalmers University of Technology in Sweden.

Reference:

S. Muller, A. Beelen, J. H. Black, S. J. Curran, C. Horellou, S. Aalto, F. Combes, M. Guelin, & C. Henkel (2012). A precise and accurate determination of the cosmic microwave background temperature at z=0.89 Astronomy & Astrophysics arXiv: 1212.5456v1