Reasons to Believe

The Right Temperature

As scientists build their case for big bang cosmology, they rely on increasing knowledge of the universe’s formation.

One component, the expansion of the universe, is revealed by the cosmological redshift found in distant galaxies. Another component, the cosmic microwave background (CMB) radiation is considered by cosmologists to be one of the best available evidences for the big bang theory. In this theory, the CMB is viewed as a remnant of the big bang that dates to about 380,000 years after the beginning. The universe had cooled to 3,000 K, which allowed electrons and protons to combine to form hydrogen atoms. At that point the universe became transparent and radiation was able to travel freely through space.

Astronomers have been gathering a growing body of evidence revealing important details about the CMB since its discovery in 1965 by Arno Penzias and Robert Wilson. These details include a uniform intensity in all directions (isotropic), a spectrum of black body radiation with a temperature of 2.7 K, and small variations in its distribution in the sky. These small variations are interpreted as the irregularities coming out of the big bang event that eventually led to the formation of stars and galaxies.

The big bang model predicts that observations at different epochs of the expanding universe (assuming the universe is approximately 13.7 billion years old) should show a cooling off of the CMB, going from its predicted original value of 3,000 K to its current measured value of 2.7 K. While earlier observations provided some evidence in support of this prediction, a new technique bolsters the case.

Astronomer R. Srianand and his colleagues reported that they’re using the ESO Very Large Telescope to detect, for the first time, the presence of the carbon monoxide molecule in a galaxy located at a distance where its light has traveled for 11 billion years. Their detection was accomplished by looking for absorption lines in the ultraviolet light coming from a more distant quasar and caused by gas in the foreground galaxy.

This observation allowed the team to estimate the CMB’s temperature, with the greatest precision to date, at the very early epoch of about 2.8 billion years after the big bang. The value they obtained is 9.15 +/- 0.07 K, which is in excellent agreement with the predicted value of 9.3 K. The same team had already broken the record for the most distant (but less precise) detection of molecular hydrogen in a galaxy that was at a distance corresponding to the universe when it was less than 1.5 billion years old (see here).

All of these observations provide important confirmation for the big bang model, and add credence to the RTB creation model that posits a beginning for the universe in accordance with the words of the Bible.

Subjects: Origin of the Universe

Dr. David Rogstad

Dr. Dave Rogstad received his PhD in physics from Caltech and worked over 30 years for NASA’s Jet Propulsion Laboratory. Though now retired, Dave continues to serve as an RTB board member and participates regularly in several RTB podcasts.