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The average of the true solar day during the course of an entire year is the mean solar day, which contains 86,400 mean solar seconds. Currently, each of these seconds is slightly longer than an SI second because Earth's mean solar day is now slightly longer than it was during the 19th century due to tidal friction. The average length of the ...
10 times the length of the previous cosmological decade, with CD 1 beginning either 10 seconds or 10 years after the Big Bang, depending on the definition. eon: 10 9 yr: Also refers to an indefinite period of time, otherwise is 1 000 000 000 years. kalpa: 4.32 × 10 9 yr: Used in Hindu mythology. About 4 320 000 000 years. exasecond: 10 18 s ...
Some common units of time in seconds are: a minute is 60 seconds; an hour is 3,600 seconds; a day is 86,400 seconds; a week is 604,800 seconds; a year (other than leap years) is 31,536,000 seconds; and a century averages 3,155,695,200 seconds; with all of the above excluding any possible leap seconds.
[9] [failed verification] Each degree was subdivided into 60 minutes and each minute into 60 seconds. [10] [11] Thus, one Babylonian degree was equal to four minutes in modern terminology, one Babylonian minute to four modern seconds, and one Babylonian second to 1 / 15 (approximately 0.067) of a modern second.
The ERA may be converted to other units; for example, the Astronomical Almanac for the Year 2017 tabulated it in degrees, minutes, and seconds. [12] As an example, the Astronomical Almanac for the Year 2017 gave the ERA at 0 h 1 January 2017 UT1 as 100° 37′ 12.4365″. [13]
5.4 × 10 83 Qs (1.7 × 10 106 years): The approximate lifespan of a supermassive black hole with a mass of 20 trillion solar masses [21] 10 10 10 76.66 {\displaystyle 10^{10^{10^{76.66}}}} Qs: The scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing an isolated black hole of stellar mass [ 22 ...
1.67 minutes (or 1 minute 40 seconds) 10 3: kilosecond: 1 000: 16.7 minutes (or 16 minutes and 40 seconds) 10 6: megasecond: 1 000 000: 11.6 days (or 11 days, 13 hours, 46 minutes and 40 seconds) 10 9: gigasecond: 1 000 000 000: 31.7 years (or 31 years, 252 days, 1 hour, 46 minutes, 40 seconds, assuming that there are 7 leap years in the interval)
At present, the rate of precession corresponds to a period of 25,772 years, so tropical year is shorter than sidereal year by 1,224.5 seconds (20 min 24.5 sec ≈ (365.24219 × 86400) / 25772). The rate itself varies somewhat with time (see Values below), so one cannot say that in exactly 25,772 years the Earth's axis will be back to where it ...