Relative dating is used to determine the celebs dating celebs

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Similarly he calculated the distance to ships at sea by noting the azimuth angle of the ship from a baseline of two widely spaced observation points a known distance apart on the shore and scaling up the distance to the ship from the dimensions of a smaller similar triangle.In this way he was able to calculate the distance to far off objects without measuring the distance directly, the basis of modern surveying.Since the average lunar month is 29.5 days, over 12 months this would produce a total of only 354 days as against a solar year of 365.25 days.To keep the calendar aligned to the seasons they added seven extra months in each period of 19 years, equivalent to the way we add an extra day in leap years.Produced from the freshwater papyrus reed, the papyrus scrolls were fragile and susceptible to decay from both moisture and excessive dryness and many of them have thus been lost, whereas the older, more durable clay cuneiform tablets from Mesopotamia have survived. Sumerian mathematics and science used a base 60 sexagesimal numeral system.Historians seem to agree that the wheel and axle were invented around 3500 B. 60 is divisible by 1,2,3,4,5,6,10,12,15,20,30 and 60 making it more convenient than using a base 10 decimal system when working with fractions.The Mesopotamians thus introduced the 60-minute hour, the 60-second minute and the 360-degree circle with each angular degree consisting of 60 seconds.The calendar adopted by the Sumerians, Babylonians and Assyrians was based 12 lunar months and seven-day weeks with 24-hour days.

Lodestone was also known in China at that time where it was known as "love stone" and is in fact quite common throughout the world.

They did not have the benefit of cheap, off the shelf, mass produced batteries. Bronze is a relatively hard alloy of copper and tin, better suited for the purpose than the much softer copper enabling improved durability of the weapons and the ability to hold a cutting edge.

For many years the telegraph, and later the telephone, industries were the only consumers of batteries in modest volumes and it wasn't until the twentieth century that new applications created the demand that made the battery a commodity item. The use of bronze for tools and weapons gradually spread to the rest of the World until it was eventually superceded by the much harder iron.

The writing was in the form of a series of wedge-shaped signs pressed into soft clay by means of a reed stylus to create simple pictures, or pictograms, each representing an object. the script progressively evolved to encompass more abstract concepts as well as phonetic functions (representing sounds, just like the modern Western alphabet) enabling the recording of messages and ideas.

The clay subsequently hardened in the Sun or was baked to form permanent tablets. For the first time news and ideas could be carried to distant places without having to rely on a messenger's memory and integrity.

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