Astronomy is widely recognized as the oldest science. Long before humans had a word for science, they were tracking the movements of the moon, stars, and sun to predict seasons, plan harvests, and mark the passage of time. The evidence for this stretches back at least 7,000 years in physical structures and possibly much further through carved bone artifacts that may represent lunar calendars dating to 25,000 years ago or more.
But the answer depends on what you mean by “science.” If you mean systematic observation of the natural world, astronomy wins by a wide margin. If you mean a formal discipline with written records and mathematical models, the picture gets more interesting.
Why Astronomy Came First
The sky was the first laboratory. When early humans shifted from nomadic life to farming, the heavens became essential to survival. Different star patterns appear at different times of year. The constellation Virgo signaled spring planting and flood risk. Orion’s rise marked harvest time and the approach of winter. The roughly 30-day cycle of lunar phases closely matched the human menstrual cycle, leading ancient peoples to associate the moon with fertility. Eclipses, terrifying and unpredictable, likely drove some of the earliest attempts at forecasting celestial events.
This wasn’t casual stargazing. People built structures specifically to track astronomical events. Nabta Playa, a stone circle in what is now the Egyptian Sahara, is roughly 7,000 years old, making it the oldest known stone circle in the world and possibly the earliest astronomical observatory. Its stones aligned with the summer solstice, which coincided with the arrival of monsoon rains. Later analysis found alignments with Arcturus, Sirius, Alpha Centauri, and the constellation Orion, with the Arcturus alignment dating to around 4800 B.C.
Stonehenge, constructed between 3100 and 2000 B.C. on England’s Salisbury Plain, served a similar purpose. Its “heelstone” aligns with the rising sun on the summer solstice, and many other megalithic sites across Europe share comparable alignments. These weren’t temples in the modern sense. They were tools for reading the sky.
The Oldest Written Records
The jump from stone alignments to written science happened in Mesopotamia. Babylonian astronomers observed and recorded celestial events every night for more than six centuries during the first millennium B.C. The oldest surviving entry in their astronomical diaries dates to 652 B.C., and the most recent to 61 B.C., with tablets recovered primarily from Babylon and Uruk.
These weren’t vague descriptions. Scribes tracked the moon’s position relative to 31 reference stars, all within 10 degrees of the ecliptic (the band of sky where the sun and planets appear to travel). They recorded the moon as being “above,” “below,” “in front of,” or “behind” a given star by a specified distance measured in cubits. They also logged planetary positions, solstices and equinoxes, the appearances of Sirius, meteors, comets, and even economic and political events alongside the celestial data.
This level of systematic, quantitative record-keeping over centuries is what separates early astronomy from other ancient knowledge systems. No other field of study from that era comes close in terms of precision or continuity.
The Nebra Sky Disk
One striking artifact bridges the gap between prehistoric monuments and Babylonian record-keeping. The Nebra Sky Disk, a bronze disk found in Germany, dates to around 1800 B.C. and is the world’s oldest known representation of a specific astronomical phenomenon. It originally displayed 32 gold stars (including the Pleiades star cluster), a gold orb representing the sun or full moon, and a crescent moon. Its practical function was helping users synchronize the lunar and solar calendars by knowing when to insert a leap month.
Later modifications added two golden arcs showing the positions of the horizon at summer and winter solstice as seen from the disk’s location. Researchers have noted that its first two phases reflect pure observational astronomy, with no religious or mythological symbolism attached. By about 1600 B.C., the disk was buried, possibly as an offering, after roughly 200 years of use.
What About Mathematics?
Mathematics has a strong claim as a rival to astronomy, and the two were deeply intertwined from the beginning. The Lebombo Bone, found in Eswatini (formerly Swaziland), dates to roughly 35,000 years ago and bears a series of notch marks that suggest tally counting. The Ishango Bone, found in what is now the Democratic Republic of Congo, was originally estimated at 8,500 years old but has since been re-dated to around 25,000 years old.
The Ishango Bone is remarkable. Its markings appear to encode several mathematical concepts at once. Two of its rows each add up to 60. One row contains the prime numbers between 10 and 20. Another row groups notches in patterns consistent with a base-10 number system (20 + 1, 20 − 1, 10 + 1, 10 − 1). A third row may illustrate multiplication by doubling, a technique later used in Egyptian arithmetic. Microscopic analysis also suggests the bone functioned as a six-month lunar phase counter.
If a lunar calendar counts as astronomy, then even these ancient bones blur the line between math and sky-watching. Early humans likely developed counting partly to track celestial cycles.
Medicine and Biology as Early Sciences
Other sciences have ancient roots but lack the same depth of early systematic practice. At Shanidar Cave in Iraq, a Neanderthal burial (Shanidar IV) from the Middle Paleolithic contained pollen from several plant species, including yarrow, cornflower, ephedra, and marshmallow. Modern analysis of these plants revealed they all have considerable therapeutic properties, suggesting the flowers may have been deliberately selected for medicinal purposes. If true, this would push some form of medicinal knowledge back tens of thousands of years, though whether Neanderthal plant use qualifies as “science” is debatable.
Formal biological science arrived much later. Aristotle, working in the fourth century B.C., created the first known system for classifying living organisms. Rather than sorting animals by a single defining trait, he grouped them by overall body similarity and then distinguished species within groups by differences in degree: leg length, beak size and shape, wingspan, and similar features. His insight that an organism’s physical traits are functionally necessary for its particular lifestyle in a particular environment anticipated evolutionary thinking by more than two thousand years. One modern scholar described Aristotle’s framework as “a spiritual ancestor of the evolutionary approach.”
Physics and the First Physical Laws
Formal physics emerged later still. Archimedes, who lived in Syracuse (Sicily) from 287 to 212 B.C., established some of the first physical laws that could be tested and expressed mathematically. His principle of buoyancy states that a body submerged in fluid experiences an upward force equal to the weight of the fluid it displaces. Legend says he discovered this while taking a bath and ran through the streets naked shouting “Eureka!” (“I have found it!”). Whether or not the story is true, he used the principle practically to determine the gold content of alloys.
Agriculture also developed systematic methods early. In the Levant, the domestication of founder crops like barley and various pulses began during the Pre-Pottery Neolithic B period, roughly 8800 to 6500 B.C. Archaeologists have found evidence of farmers experimenting with different legume species at sites like Ahihud, selectively growing some that would eventually become staple crops. This trial-and-error approach to plant selection resembles an early form of applied science, though it lacked the theoretical framework that defines a formal discipline.
So What Counts as “Science”?
The answer to “what is the oldest science” ultimately depends on your definition. If science means any systematic observation of nature used to make predictions, then astronomy has been practiced for at least 7,000 years and possibly 25,000 or more. If science requires written quantitative records, Babylonian astronomy from around 652 B.C. is the clearest starting point. If it requires testable laws and mathematical proofs, you’re looking at Greek thinkers like Archimedes in the third century B.C.
By any of these definitions, astronomy holds the top spot. It was the first field where humans moved beyond survival instinct to deliberately, repeatedly, and precisely measure the natural world, and it remained the most advanced science for thousands of years.