Top 10 time facts

Nuclear bomb explosions. The rapatronic cameras are capable of recording a still image with an exposure time as brief as 10 nanoseconds (that would give 100 million frames per second if the camera was capable to do multiple pictures). The camera uses two polarizing filters mounted with their polarization angles at 90° to each other and a Faraday cell which briefly changes the polarization plane of light passing through it, acting as a shutter.

Quasars. A quasar is an extremely energetic source of radiation powered by accretion disc around galaxy's central supermassive black hole. Quasars were much more common in the early universe, as all known quasars are extremely distant.

UTC+14. Time zones range from UTC-12 to UTC+14. UTC+14 stretches as far as 30° east of the 180° longitude line and creates a large fold in the International Date Line. In Kiribati (UTC+14), the local time is the same as in Hawaiʻi (UTC−10:00), but the date is one day ahead. It is also 26 hours ahead of Baker Island (UTC−12:00).

India is one of the few countries that use single time zone with a 30-minute increment from UTC. The country's east–west distance covers 28 degrees of longitude, resulting in two hours difference in astronomical time. Since authorities decided to have one time zone for the whole country, they had to adjust it precisely.

23 h 56 min 05 s. Sidereal time is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. It is a time scale that is based on the Earth's rate of rotation measured relative to the fixed stars rather than the Sun.

Venus year (the time it takes it to rotate around the Sun) is equal to 225 Earth days, and its day (the time it takes it to rotate on its axis) equals 243 Earth days.

Ante Meridiem. “Ante meridiem” is Latin for “before noon”. Although “AM/PM” is especially common in English-speaking countries, these acronyms come actually from Latin.

About 1 hour. The length of stars trails is pretty much the same as the distance travelled by an hour hand of clock during 30 minutes. But the Earth rotates twice as slow compared to the hour hand of a clock (one rotation per day, while clock's hour hand makes two).

31 Dec 2000. There was no year number zero. So, the first century started on 1 Jan 1. Similarly, 21th century started 1 Jan 2001.

Pope Gregory XIII. Gregory XIII was pope during the period from 13 May 1572 until 10 April 1585. The Gregorian calendar, also called the Western Calendar, was introduced by him in 1582 with the Bull Inter Gravissimas. The Gregorian calendar basically a refinement of the Julian calendar. The Gregorian reform modified the Julian calendar's scheme of leap years, changing the mean length of the calendar year from 365.25 days to 365.2425 days.