Speed of light they appeared 13 billion years ago, when the universe was less than a billion years old. The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the evolution of stars, of galaxies, and of the universe itself. Astronomical distances are sometimes expressed in light-years, especially in popular science publications and media. A light-year is the distance light travels in one year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri,
History of measurement systems in Pakistan of Pakistan adopted the International System of Units (SI) Kos is an ancient unit of distance used in South Asia which is about 2.25 miles. Kos may also refer to about 1.8 km (1⅛ mile) or 3.2 km (2 miles). The Mughal Empire used Farsang (Parsang) for distance, which was in principle the distance a horse would walk in an hour, about 3 miles = 12,000 cubits. A Kanal is a unit of area, equivalent to 5445 square feet or one-eighth of an acre. It is mainly used in Punjab province of Pakistan. Under British rule the Marla and Kanal