Temperature of the Cosmic Microwave Background Radiation

For thousands of years the Bible stood alone among all theological, philosophical, and scientific texts in making the claim we live in a big bang universe. Bible authors described all the fundamental features of big bang cosmology,¹ features unknown to astronomers until the twentieth century. Scripture’s depictions of these characteristics rank as one of the more spectacular scientific evidences for the divine inspiration of the Bible’s authors. Consequently, anything that strengthens the evidence for the big bang creation model bolsters the case for biblical inspiration and inerrancy.

Scripture has much to say about the universe. Specific to the big bang creation event it states:

1. The universe arose from a singularity beginning. That is, God created the universe of matter, energy, space, and time independent of any matter, energy, space, and time. (Genesis 1:1, 2:3–4; Psalm 148:5; Isaiah 40:26, 42:5, 45:18; John 1:3; Colossians 1:15–17; Hebrews 11:3.)
2. The universe undergoes continual expansion from the cosmic creation event. (Job 9:8; Psalm 104:2; Isaiah 40:22, 42:5, 44:24, 45:12, 48:13, 51:13; Jeremiah 10:12, 51:15; Zechariah 12:1.)
3. The universe’s physical laws are constant throughout its history. (Genesis 2–3; Jeremiah 33:25; Romans 8:20–22; Revelation 21:1–5.)
4. The entire universe is subject to a pervasive law of decay, also known as the second law of thermodynamics, the law of entropy, or Murphy’s Law. (Romans 8:18–23.)

The above-mentioned cosmic features imply a specified cooling history for the universe. A specified cooling history indicates that the universe will manifest a pervasive background radiation and that the spectrum of that radiation will perfectly match that of a black body radiator. When the four features are combined with measurements of the age of the universe and the relative abundance of elements in the universe, they suggest a specified temperature for the cosmic background radiation.

Recently, astronomer D. J. Fixsen of the University of Maryland and the Goddard Space Flight Center analyzed data from both the Far Infrared Absolute Spectrophotometer (FIRAS) and the Wilkinson Microwave Anisotropy Probe (WMAP) to produce the most accurate measurement of the temperature of the cosmic background radiation². His goal was to further the quest for precision cosmology. Up until now, calculations of certain parameters of big bang cosmology had presumed a cosmic background radiation temperature of 2.725° Kelvin (2.725° Centigrade above absolute zero). A more accurate temperature measurement would yield a more detailed and firmly established set of parameters for the big bang creation model. Fixsen intended, too, to test the consistency of independent measurements of the cosmic background radiation’s temperature.

Fixsen used data from the WMAP to carefully calibrate the FIRAS experiment. By this means he determined that the temperature of the cosmic background radiation = 2.7260 ± 0.0013° Kelvin. He then compared this measurement against all other precision measurements of the cosmic background radiation and found them all to be remarkably consistent.

Combining both his and all other precision measurements, Fixsen produced the most accurate calculation to date. The cosmic background radiation temperature = 2.72548 ± 0.00057° Kelvin.

This analysis achieved three results. First, it strengthened a key prediction of the big bang creation model, namely that a pervasive, highly uniform background radiation exists. The standard deviation (probable error) in Fixsen’s determination is 4,781 times smaller than the temperature value for the cosmic background radiation temperature, leaving no doubt of its reality. Likewise, the consistency among the independent calculations testifies to the reality of the cosmic background radiation.

Second, Fixsen’s measurement falsifies young-earth creationist models. There is no way the radiation from the cosmic creation event, which starts out at an infinitely or near infinitely high temperature, could cool down to just 2.72548° Kelvin in only thousands or tens of thousands of years. To explain how cold the cosmic background radiation is the universe must be billions of years old.

Third, by giving cosmologists a more precise determination of the temperature of the cosmic background radiation, Fixsen has enabled them to produce more accurately established cosmological parameters. Researchers will be able to increase the robustness of big bang creation models. We at RTB predict these developments will continue to add evidence in support of biblical cosmology and inerrancy.