One of the greatest enigmas in the studies of ancient history is the emergence of the Sumerians, who supposedly migrated from some unknown place and, with no apparent preliminary development, immediately began to build cities, observatories, libraries, and the civil infrastructures which accompany such undertakings.
Only a fraction of the known Sumerian writing has been translated, and the translation efforts have been hampered by the fact that no known language has been found that relates to Sumerian. Bilingual

The Sumerians had a very advanced financial and economic system, complete with stock markets and commodities trading.

Sumerian-Akkadian documents provided some of the initial keys, but linguistic comparisons are still difficult since Akkadian and other languages borrowed the cuneiform style of writing used by the Sumerians, and a great deal of confusion still exists.
The amazing architecture of their cities and ziggurats is fairly well known, but there are many other accomplishments which are not so well known. They had a very advanced financial and economic system, complete with stock markets and commodities trading. (There were even complex accounting tables which reconciled lunar and solar calendars in the calculation of debt, annual percentages, and compound interest earnings.)
There was thriving commerce along the Euphrates River, where large, pontoon barges carried goods from city to city. Advanced medicine, law, metallurgy and chemurgy were practiced, and sophisticated

Their earliest writings show that they knew the three-dimensional arrangement and mechanics of the Solar System.

agriculture, with irrigation canals, crop rotation, and the utilization of grains for non-culinary use was abundant.
Finely crafted artwork such as pottery, sculptures, and paintings abounded, and there was even a large market for cosmetics. Special schools taught art, music, and theater, and graduates from these schools formed an important, professional class.
But perhaps the most amazing knowledge possessed by the Sumerians was in the field of astronomy. Their earliest writings show that they knew the three-dimensional arrangement and mechanics of the Solar System. They knew the Sun (Utu) was a sphere, and that all of the planets (Mul-Apin), including the Earth, traveled around it. They created accurate tables of lunar and solar eclipses, and knew of the phases of Venus. They claimed twelve celestial bodies inhabited the Solar System, (Sun, Moon, and ten planets) and correctly divided them into two categories: inner and outer planets.
They acknowledged that the outermost three could not be seen, but they correctly identified the colors of the first two—green and blue, respectively. The fact that we only recognize nine planets (until the recent demotion of Pluto) is potentially solved by a variety of conflicting Sumerian legends involving the destruction of one of the planets—often in conjunction with the time of the flood.
Supposedly a planet named Nibiru, traveling between the first and second outer worlds (Mars and Jupiter), once existed in the regions now occupied by the Asteroid Belt, but was either destroyed or somehow ‘went away’. Whatever the case, they were convinced it

The Sumerians accurately knew that it takes 25,800 years for this circle to return to its original "North Star".

should be there. (For the sake of The Days of Peleg, it was assumed destroyed, and the object seen by astronomers in Chapter 5 was most likely Vesta, an asteroid orbiting in the same path—and the only one regularly visible to the naked eye).
However, the most remarkable item in the vast reservoir of Sumerian astronomical awareness is the accurate measurement of the Earth’s precession. This is the slight wobble in the Earth’s axis which causes a line from the North Pole to draw a slow circle in the sky as the years progress. As a result, the "North Star" can change over the course of several centuries. The Sumerians accurately knew that it takes 25,800 years for this circle to return to its original "North Star", and made reference to it (calling it the "Great Year") in some of their writings as a warning to future generations of navigators and astronomers.
Now it must be stated clearly that there is absolutely no indication that the Sumerians had any of the necessary equipment, or even the optical tools needed for making these observations or determining

Knowing that something is possible (and perhaps once existed) makes it much easier and more likely to accomplish it—or replicate it.

these measurements. They simply knew it. Many Sumerian legends claim that this knowledge came from ancient races, or gods from before the flood.
In the context of The Days of Peleg, it makes perfect sense that, although all monuments and manifestation of advanced science were destroyed during the flood, the knowledge of the various sciences would have survived. Knowing that something is possible (and perhaps once existed) makes it much easier and more likely to accomplish it—or replicate it.
It should also be noted that subsequent civilizations, such as Babylonia, Egypt, and Arabia also knew a great deal of astronomical knowledge, including precession and other planetary formulae, but were only able to use this information for calculation purposes such as eclipses and the development of astrological charts. There is no indication that these later civilizations understood the foundations of this knowledge. Indeed, they all freely admit their astronomical prowess was inherited from the Sumerians.
Strangely, later Sumerian (and Babylonian) writings indicate a loss of astronomical comprehension; referring to the sky as a bowl inverted upon a flat earth. By the time these regressive Sumerian astronomers were writing such things, Egyptian and Greek mathematician/astronomers were measuring the circumference of the Earth and the distance to the moon.
Rather than the steady, Darwinian progress of social and technological achievements, ancient history is, instead, a testimony to the rise and fall of numerous, co-existing civilizations and the many times that scientific knowledge has arisen, atrophied, and ultimately been buried by the passage of time.