# How much time is there in 1 second

1 mean solar unit = 1.00273791 sidereal units
1 sidereal unit = 0.99726957 mean solar unit
1 microsecond = 0.000001 second

1 second = 1,000,000 microseconds
= 0.01666667 minute
= 0.00027778 hour
= 0.00001157 day

1 minute = 60 seconds
= 0.01666667 hour
= 0.00069444 day

1 hour = 3.600 seconds
= 60 minutes
= 0.04166667 day

1 mean solar day = 24h 03m 56s55536 of mean sidereal time
= 1 rotation of earth with respect to sun (mean)
= 1.00273791 rotations of earth w / respect to Aries (mean)
= 1.0027378118868 rotations of earth w / respect to stars (mean)

1 mean sidereal day = 23h 56m 04s09054 of mean solar time

1 sidereal month = 27.321661 days
= 27d 07h 43m 11s5

1 synodical month = 29.530588 days
= 29d 12h 44m 02s8

1 tropical (normal) year = 31,556,925,975 seconds
= 525,948.766 minutes
= 8,765.8128 hours
= 365d.242198 -0d.0000000614 (t-1900), where t = the year
= 365d 05h 48m 46s (-) 0s 0053t

1 sidereal year = 365d.25636042 + 0.0000000011 (t-1900),
where t = the year = 365d 06h 09m 09s.5 (+) 0s.0001t

1 normal calendar year = 31,536,000 seconds
= 525,600 minutes
= 8,760 hours
= 365 days

1 calendar year (leap) = 31,622,400 seconds
= 528.040 minutes
= 8,784 hours
= 366 days

1 light-year = 9,460,000,000,000 kilometers
= 5,880,000,000,000 statute miles
= 5,110,000,000,000 nautical miles
= 63,240 astronomical units
= 0.3066 parsecs

1 parsec = 30,860,000,000,000 kilometers
= 19,170,000,000,000 statute miles
= 16,660,000,000,000 NM
= 206,300 astronomical units
= 3,262 light years

1 astronomical unit = 149,600,000 kilometers
= 92,960,000 statute miles
= 80,780,000 nautical miles
= 499s.012 light-time
= mean distance, earth to sun

Mean distance earth-moon = 384,400 kilometers
= 238,855 statute miles
= 207,559 nautical miles

Mean distance earth to sun = 149,600,000 kilometers
= 92,957,000 statute miles
= 80,780,000 nautical miles
= 1 astronomical unit

Sun's diameter = 1,392,000 kilometers
= 865,000 statute miles
= 752,000 nautical miles

Speed ​​of sun relative to neighboring stars = 19.4 kilometers per second
= 12.1 statute miles per second
= 10.5 nautical miles per second

Orbital speed of earth = 29.8 kilometers per second
= 18.5 statute miles per second
= 16.1 nautical miles per second

Obliquity of the ecliptic = 23º 27 '08 ".26-0" .4684 (t-1900), where t = the year

General precession of the equinoxes = 50 ".2564 + 0" .000222 (t - 1900) per year, where t = the year

Precession of the equinoxes in right ascension = 46 ".0850 + 0" .000279 (t - 1900) per year, where t = the year

Precession of the equinoxes in declination = 20 ".0468-0" .000085 (t - 1900) per year, where t = the year