The Bible and Astronomy
by Hector Avalos
The following article is from Free
Inquiry magazine, Volume 18, Number 4.
Long before telescopes and sophisticated instruments, ancient peoples looked to the
heavens for answers to the basic questions of life. From the very first verse, the Bible,
the most influential collection of books in Western civilization, purports to provide
answers to some of these questions, claiming that the Hebrew god created the heavens
(Genesis 1:1) and that he made the Earth for human beings to inhabit (Isaiah 45:18).
Heavenly luminaries were formed to provide light for Earth and markers for the seasons
(Genesis 1:14-16). The Earth was the center of the biblical universe.
The relationship between the Bible and modern astronomy has been very complicated and
often turbulent. For most of the last two thousand years, any research on astronomy had to
follow the biblical interpretation of the Church, as the case of Galileo in the
seventeenth century illustrated. Accordingly, many scientists would argue that, for modern
astronomy to be born, biblical cosmology had to die.
Galileo vs. Ptolemy (and the Church)
Galileo took one of the first steps leading toward the death of biblical cosmology by
mounting a systematic challenge to the biblical notion that the Earth was the center of
the universe. The centrality of Earth had long been associated with the cosmologies of
Aristotle and Ptolemy that had been adopted as the official teaching of the Church. These
cosmologists held that an immovable Earth was orbited by concentric spheres in which the
various planets and stars were embedded. A complex series of circular motions by each
sphere and the associated celestial bodies was purported to account for all observable
heavenly motions, including the apparent retrograde motion of some planets. The heavenly
bodies, such as the Moon and Sun, were perfectly homogeneous in their composition and
In contrast, Galileo sought to confirm the theory, most forcefully presented in the
sixteenth century by the Polish astronomer Copernicus in his De Revolutionibus
Orbium Coelestium, that the Sun was the center of the universe. As Alexander Koyr,
William Shea, and other historians of science have noted, most of Galileo's arguments were
no better empirically than those of Ptolemy, and definitive confirmation of the Copernican
system was found long after Galileo's death.
Galileo's certainty seems to have rested on the assumption that mathematical simplicity
is a guide to truth. Even if two otherwise contrary systems could account for heavenly
motions, the simpler mathematical model should be preferred. Galileo's faith in
mathematical simplicity is evident in his famous Dialogo (after 1744 titled Dialogue
Concerning the Two Chief World Systems, Ptolemaic and Copernican):
Who is going to believe that nature ... has chosen to make an immense number of very
huge bodies move with incalculable speed, to achieve what could have been done by a
moderate movement of one single body around its own center?
But even if Galileo's mathematically simple model did not constitute proof that the
universe actually worked in this manner, Galileo announced other discoveries that cast
doubt on Aristotelian-Ptolemaic cosmology. Such discoveries were facilitated by Galileo's
innovative use of the telescope to explore the heavens beginning around 1609. Galileo
showed, for example, that the Moon's surface has mountains and valleys, and is not
perfectly smooth as Aristotle postulated; that the Sun has spots, not a homogeneous
surface; and that Venus has phases, which would not be expected if Venus moved uniformly
around the Earth.
The Church reacted against such challenges by placing Copernicus' De
Revolutionibus on the index of prohibited books in 1616, 73 years after its
publication and indicating that the Church saw no early threat by this
"revolutionary" work. In 1633 Galileo was tried and found guilty of teaching the
Copernican system. His sentence included imprisonment, which was commuted to house arrest
at his home near Florence for the remaining years of his life.
Eventually, modern cosmology established the validity of the heliocentric theory.
Moreover, modern cosmology showed that the sequence of cosmogonic events in Genesis 1, if
interpreted literally, is not correct. Stars were formed on the fourth day of creation in
Genesis 1:16, whereas modern astronomy has established that stars are still being formed
today. Water on Earth exists before any other principal component in Genesis 1:1-3,
whereas in modern cosmology our watery planet is a relatively late product. Even the need
for a creator has been challenged. In his introduction to Steven Hawking's A Brief
History of Time, Carl Sagan observed that Hawking outlines "a universe with no
edge in space, no beginning or end in time, and nothing for a Creator to do."
In addition, developments in biblical scholarship, especially in the nineteenth
century, undermined the idea of a unified biblical cosmology. Most modern biblical
scholars identify at least two different creation stories in Genesis, one in Genesis
1:1-2:4a and another in Genesis 2:4b-2:25. Among a number of differences, the first story
places the creation of all animals before the creation, on the sixth day, of man and woman
together. The second creation story has a different sequence: the human male (Gen. 2:7),
then all the animals (Gen. 2:19), and finally the human female (Gen. 2:21-22).
Biblical cosmology is preserved in some circles, most notably in the writings of Henry
Morris, John Whitcomb, and other fundamentalist Christians known as
"creationists." Most creationists still uphold the basic sequences and
chronology of Genesis 1, not Genesis 2, as the paradigmatic creation story even if they
disagree on whether to interpret the length of the days literally, or as more prolonged
periods of time. And, as a secular biblical scholar, I also see the continuing, and in my
opinion misguided, attempts by some modern astronomers to harmonize astronomy and the
A Primer in Biblical Cosmology(ies)
The most common view found in the biblical texts indicates that the Hebrews thought of
a tri-partite universe (heaven, Earth, and underworld), with the sky as a sort of metallic
dome. On the other side of the walls of this dome were the storehouses for rain and snow.
Rain occurred, for example, when the doors or windows of these storehouses were opened by
God as in Genesis 7:11-12. The edge of this dome, outlined by the horizon, rested on
pillars or mountains which had roots extending deep into the Earth (see Job 26:11). The
Earth, which was declared to be immovable (Psalm 104:5), was a disk supported on water.
Rivers were often seen as originating in this underground water. See Genesis 2:6 where
"stream" rather than the "mist" of the King James Version is a better
The Hebrew god and his divine retinue inhabited the heavens, although he also visited
the Earth to see what human beings were doing (Genesis 11:5). The idea of persons living
in heaven was an idea popularized by Christianity. However, the books attributed to a
figure called Enoch reflect the existence of a vigorous pre-Christian Jewish literature
which speaks of temporary visits and tours of the heavenly realms. These narratives are
usually viewed as works of the imagination and theology by biblical scholars, but they
have become evidence of space travel in antiquity for many UFO enthusiasts.
Many modern astronomers evince misunderstandings of biblical cosmology. For example,
Robert Jastrow writes in God and the Astronomers: "The details differ,
but the essential elements in the astronomical and biblical accounts of Genesis are the
same: the chain of events leading to man commenced suddenly and sharply at a definite
moment in time, in a flash of light and energy."
Another possibly misguided effort centers on providing scientific explanations for what
may be purely literary phenomena. One case involves the Sun and Moon standing still in
Joshua's battle at Gibeon (Joshua 10:12-13):
On the day when the Lord gave the Amorites over to the Israelites, Joshua spoke to the
Lord; and he said in the sight of Israel, "Sun, stand still at Gibeon, and Moon, in
the valley of Aijalon." And the sun stood still, and the moon stopped, until the
nation took vengeance on their enemies. Is this not written in the Book of Jashar? The sun
stopped in midheaven, and did not hurry to set for about a whole day.
This command by Joshua is most probably a literary motif also found in many other
battle accounts of the ancient Near East. Consider in the Iliad, the famous Greek epic of
the early first millennium b.c.e., that Agamemnon, the king of the Greeks, requests Zeus
grant that "the sun set not, neither darkness come upon us until I have cast down in
headlong ruin the halls of Priam."
Astronomers have also sought to explain the Star of Bethlehem (Matthew 2:2-10) without
any apparent attention to possible literary motivations. For example, a recent article in Popular
Mechanics reports that Ivor Bulmer Thomas has attempted to link the Star of
Bethlehem with a conjunction of Jupiter and Saturn in May of 7 b.c.e., or a conjunction of
Mars, Jupiter, and Saturn in 6 b.c.e. Another astronomer argues on the basis of Chinese
records, however, that a nova occurring in the spring of 5 b.c.e. may be a more probable
As is the case with references to eclipses, it is certainly possible that the author of
Matthew was referring to an authentic astronomical event in a general sense - a
conjunction of luminaries. It is also well known, however, that in the ancient world
astronomical signs were associated, almost routinely and without much precision, with
people favored by the authors. Attempting to provide scientific explanations for these
literary motifs may be as misguided as providing scientific explanations for how Superman
flies or which astronomical event corresponds to the explosion of the planet Krypton.
Perhaps more often than scientists who seek to correlate the Bible and science,
religious commentators will attempt to harmonize new scientific discoveries with biblical
references. After the formulation of the law of gravitation, a few conservative biblical
commentators sought to explain "chains" and "cords" in the Job 38:31
passage, "Can you bind the chains of the Pleiades, or loose the cords of Orion?"
as reflecting biblical knowledge of gravitational bonds. The problem is that we really do
not know that the relevant Hebrew words referred to those specific constellations, if any
at all. "Cords" and "chains" may refer to some design that the
ancients saw, like Orion's starry belt, rather than any theory of gravitation.
A similar situation obtains in Isaiah 40:22, which is sometimes cited to support the
idea that biblical authors knew of the spherical shape of the Earth: "It is he who
sits above the circle of the Earth, and its inhabitants are like grasshoppers; who
stretches out the heavens like a curtain, and spreads them like a tent to live in."
Some argue that knowledge of the Earth's sphericity is more than can be expected in
ancient times, and that such knowledge must therefore be attributed to some supernatural
source. However, the Hebrew word translated here as "the circle" most probably
refers to the circle traced by the horizon and is not reference to the sphericity of the
Earth at all. Languages related to Hebrew have the same word-root to refer to the horizon.
Moreover, even if the Hebrew authors knew about the sphericity of the Earth, such
knowledge would not require any supernatural explanation. After all, Eratosthenes of
Alexandria, an ancient Greek mathematician active in the third century b.c.e., not only
knew that the world was round but also used trigonometry to measure the size of its
circumference to a respectable degree of accuracy.
Why Harmonize the Bible and Astronomy?
The motives for attempting to harmonize astronomy and the Bible are complex. A common
one is to unify ethical and scientific systems of "truth." The desire to
validate the social and ethical policies of the Bible is clearly at the heart of some
attempts to show that the Bible is reliable in all that it teaches. Protestant theologian
Bernard Ramm provides and example of this line of reasoning in The Christian View of
Science and Scripture:
The theological, the ethical, and the practical are so conjoined in the Bible with the
statements about Nature or creation that it is impossible to separate them, and to impugn
one is to impugn the other.
In other words, if the Bible cannot be trusted concerning its truth claims about the
origin, structure, and purpose of the universe, how can it be trusted to provide reliable
information about ethics? Any scientific disconfirmation of biblical cosmology will result
in the devaluation of the biblical ethical system.
In general, for scientists who do not think that ethics should be built on a biblical
foundation, the harmony of the Bible with astronomy is not important.
Across the Great Divide
Galileo was finally exonerated by Pope John Paul II in 1992, which is yet another
signal that the literal biblical interpretation of the origin and structure of the
universe has been largely overthrown. Yet biblical ideas have not disappeared completely.
In their most vigorous form, they are still found in the writings of the so-called
creationists. In a weakened form, they are still found in the work of some respected
astronomers. Both forms seem to be motivated by the desire to preserve two important
institutions, science and religion. It is often the case that such astronomers do not use
the same degree of rigor and critical approach to the Bible that they might use in their
own field, and the case is the same for many biblical commentators who seek to use
astronomy to buttress religious claims. Astronomers and biblical scholars need to interact
more than ever in order to avoid some basic misunderstandings of both the Bible and
All biblical quotations are from the New Revised Standard Version, National Council of
Churches of Christ in the United States of America, (Nashville, Tenn.: Thomas Nelson
This article is published with the permission of the author and adapted from his
"Heavenly Conflicts: The Bible and Astronomy," which appeared in the March-April
Hector Avalos is Associate Professor of Religious Studies at Iowa State University in Ames, where he was named the
1996 Professor of the Year. He also serves as Executive Director for the Committee for the Scientific Examination