Reasons to Believe

Ancient Egyptian Astronomy Yields New Discoveries

A team of Finnish physicists and world culture experts has integrated astronomical research on a certain star stretching over three millennia to make new discoveries that have implications far beyond what they discerned.1 Specifically, the research demonstrates that ancient observers, by incorporating what they learned about the heavens into their belief systems, made measurements of such high precision that they can be used to solve major problems in present-day astrophysics.

The star, Algol, is in the constellation Perseus. It is the brightest eclipsing binary (two-star system) in the sky. Every 2.867 days the dimmer of the two stars eclipses the brighter such that instead of Algol appearing to the naked eye at magnitude 2.1 (approximately equal to the brightness of the north star, Polaris) it dims to magnitude 3.4 (a little fainter than Albireo, the star at the foot of the northern cross, also known as Cygnus or the swan).

The two stars of Algol are separated by only 7.6 million miles (a third star orbits the binary at a distance of 250 million miles). The separation of the stars making up the eclipsing binary is so small that the larger-diameter star is losing mass to the smaller-diameter star. Observations of the Algol system at radio and x-ray wavelengths have enabled astronomers to model in great detail the mass transfer between the two stars. This model predicts that the period between eclipses will gradually lengthen by a specified amount. Additionally, accurate observations of the change in the period of Algol’s eclipses potentially can test fine details in astronomers’ models of stellar burning histories and atmospheres.

The problem with measuring Algol’s period change is that the rate of change is so small that even over the 230-year time span of which astronomers have been measuring Algol’s period, the difference is too small to test their stellar models. It was at this point that the Finnish physicists consulted world culture experts to determine if any of the ancient astronomers had noticed the variability of Algol and perhaps even measured its period.

Those experts noted that ancient Egyptian scribes observed bright stars for religious reasons during every clear night. Algol, called “the raging one” by ancient Egyptians (Rosh ha Satan, or Satan’s head, in Hebrew folklore and ra’s al-ghul, or the demon star, in Arabic), factored into the scribes’ determination of which days of the year were unlucky. The culture specialists discovered that the Cairo Calendar, dated to 1271–1163 BC, was a stellar almanac that included extensive measurements of Algol’s period. A careful analysis of the ancient Egyptian measurements showed that Algol’s period was 2.850 days in 1224 BC. Presently, it is 2.867328 days. This change in Algol’s period over 3,236 years yields a rate of mass transfer from Algol A to Algol B of 2.2 x 10-7 solar masses per year. This value agrees with the best-fitting stellar burning models, which predict a mass transfer of 2.9 x 10-7 solar masses per year.


The Finnish team ended their investigation with the conclusion that the change in Algol’s period matches the best stellar burning models for the Algol system. However, beyond the raw science there are several theological implications worthy of mention.

1. Thanks to the diligent work of ancient Egyptian astronomers, modern-day astronomers have gained assurance that their stellar burning and stellar atmosphere models are very good descriptions of the physical reality of stars. Such assurance means that evidence for the design of stars for humanity’s benefit are secure and can be exploited as tools to help bring nonbelievers to faith in Christ.

2. The integration of ancient Egyptian and modern-day astronomy establishes beyond any reasonable doubt that Algol’s stars have experienced nuclear burning for 450 million years. Confirmation of the accuracy and reliability of stellar burning models in general yields yet one more proof that stars have been shining for time periods ranging from millions to billions of years. Consequently, young-earth creationist models (positing stellar ages less than 10,000 years) have suffered another refutation.

3. Complementarianism, the popular view among theistic evolutionists and evolutionary creationists that the Bible and science complement (but do not necessarily fully integrate with) one another has been refuted, at least in part, by the Finnish team’s work. Complementarians interpret the Bible as saying little about natural history and science as saying nothing about spirituality and moral ethics. For example, Wheaton college theologian John Walton writes, “Science cannot offer an unbiblical view of material origins because there is no biblical view of material origins.”2 Walton’s explanation for this apparent silence is that for the ancient Israelites and their contemporaries “the material cosmos was of little significance to them.”3 Ancient Egyptian research on Algol argues otherwise. The ancients did see a connection between the material world and their religious beliefs—an idea consistent with a biblical psalm:

When I consider your heavens,
the work of your fingers,
the moon and the stars,
which you have set in place,
what is mankind that you are mindful of them,
human beings that you care for them?
(Psalm 8:3–4)

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.

1. L. Jetsu et al., “Did the Ancient Egyptians Record the Period of the Eclipsing Binary Algol—The Raging One?” Astrophysical Journal 773 (August 10, 2013): id. 1.

2. John H. Walton, The Lost World of Genesis One: Ancient Cosmology and the Origins Debate (Downers Grove, IL: InterVarsity, 2009), 113.

3. Ibid.