Parsec but in globular clusters the stellar density could be from 100 to 1000 per cubic parsec. Parsec The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System. A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond, which corresponds to astronomical units. One parsec is equal to about 3.26 light-years (30 trillion km or 19 trillion miles) in length. The nearest star, Proxima Centauri, is about from the Sun. Most of the stars visible to the unaided eye in the night
Long-distance running – all-weather tracks, roads and natural terrain, respectively. Typical long-distance track races range from 3000 metres to 10,000 metres (6.2 miles), cross country races usually cover 5 to 12 km (3 to 7½ miles), while road races can be significantly longer, reaching 100 kilometres (60 miles) and beyond. In collegiate cross country races in the United States, men race 8000 or 10000 meters, depending on their division, whereas women race 6000 meters . The Summer Olympics features three long-distance running events: the 5000 metres, 10,000 metres and marathon (42.195 kilometres, or 26 miles and 385 yards). Since the late 1980s,