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,
Two miles Kenyan Daniel Komen in Hechtel, Belgium on 19 July 1997. The women's record is 8:58.58, set by Ethiopian Meseret Defar in Brussels, Belgium on 14 September 2007. Note: this list only covers boys because the history of 2 mile running largely occurred before Title IX, before high school girls were allowed to compete, which occurred about the same time as conversion to metric distances. Two miles The 2 mile (10,560 feet or exactly 3,218.688 metres) is a historic running distance. Like the mile run, it is still contested at some invitational meets, perhaps because it provides an easier record to