Mathematical decimal system introduced in 4BC
On 23 September 1999 NASA scientists lost the $100 million Mars Climate Orbiter because they instructed the craft in imperial (inches and feet) instead of metric (metres) measurements. It sent the probe, which was set up for metric data, off course and burning up in the Mars atmosphere.
The first decimal system was introduced in the 4th Century BC by the Sumerians of Mesopotamia, to whom the invention of writing is credited. They based their numerical system on powers of 60 subdivided into multiples of 10. It was from this system that Sumero-Babylonians developed the time system that we use today: each hour is divided into 60 minutes, which are divided into 60 seconds. However, they did not have a symbol for zero, which was introduced by Arabians only toward the end of the first millennium BC. It is thought that the zero could have been devised by Indian Hindu mathematicians because the concept of nothing was important in their early religion and philosophy.
