Earth Rotation: HQ
About | Information | History | Online | Facts | Discovery
Rotation period: Earth's rotation period relative to the Sun (its mean solar day) is 86,400 seconds of mean solar time. Each of these seconds is slightly longer than an SI second because Earth's solar day is now slightly longer than it was during the 19th century due to tidal acceleration. The mean solar second between 1750 and 1892 was chosen in 1895 by Simon Newcomb as the independent unit of time in his Tables of the Sun. These tables were used to calculate the world's ephemerides between 1900 and 1983, so this second became known as the ephemeris second. The SI second was made equal to the ephemeris second in 1967 Earth's rotation period relative to the fixed stars, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86,164.098 903 691 seconds of mean solar time (UT1) (23h 56m 4.098 903 691s Earth's rotation period relative to the precessing or moving mean vernal equinox, misnamed its sidereal day is 86,164.090 530 832 88 seconds of mean solar time (UT1) (23h 56m 4.090 530 832 88s). Thus the sidereal day is shorter than the stellar day by about 8.4 ms. The length of the mean solar day in SI seconds is available from the IERS for the periods 1623 - 2005 and 1962 - 2005. Recently (1999 - 2005) the average annual length of the mean solar day in excess of 86,400 SI seconds has varied between 0.3 ms and 1 ms, which must be added to both the stellar and sidereal days given in mean solar time above to obtain their lengths in SI seconds. The angular speed of Earth's rotation in inertial space is 7.2921159 × 10−5 radians per SI second (mean solar second).Multiplying by (180°/π radians)×(86,400 seconds/mean solar day) yields 360.9856°/mean solar day, indicating that Earth rotates more than 360° relative to the fixed stars in one solar day. Earth's movement along its nearly circular orbit while it is rotating once around its axis requires that Earth rotate slightly more than once relative to the fixed stars before the mean Sun can pass overhead again, even though it rotates only once (360°) relative to the mean Sun. Multiplying the value in rad/s by Earth's equatorial radius of 6,378,137 m (WGS84 ellipsoid) (factors of 2π radians needed by both cancel) yields an equatorial speed of 465.1 m/s, 1,674.4 km/h or 1,040.4 mi/h. Some sources state that Earth's equatorial speed is slightly less, or 1,669.8 km/h. This is obtained by dividing Earth's equatorial circumference by 24 hours. However, the use of only one circumference unwittingly implies only one rotation in inertial space, so the corresponding time unit must be a sidereal hour. This is confirmed by multiplying by the number of sidereal days in one mean solar day, 1.002 737 909 350 795, which yields the equatorial speed in mean solar hours given above of 1,674.4 km/h. The permanent monitoring of the Earth's rotation requires the use of Very Long Baseline Interferometry coordinated with the Global Positioning System, Satellite laser ranging, and other satellite techniques. This provides the absolute reference for the determination of universal time, precession, and nutation. Over millions of years, the rotation is significantly slowed by gravitational interactions with the Moon: see tidal acceleration. However some large scale events, such as the 2004 Indian Ocean earthquake, have caused the rotation to speed up by around 3 microseconds.
Comments
-
Wow, that looks so real!😱
-
+Fabiotech, why are the clouds not moving? Because it is an animation, correct? And very detailed realistic cloud movements even in CGI are extremely time-consuming; so you have none. But, my real, pertinent question is, why is there no actual live video of the Earth rotating from space? With apparently 23,000 satellites in orbit, today we have a handful of photos from the 1950s and 1960s of the Earth in orbit; and few or no videos (what comes from the Space Station looks like your animation: a computerised composite). Why is this?
-
What is the music playing in the background? And thank you for the visual!
-
zoor jovan bo ;)
-
thanks Kurdistan..
-
I loved it like how I love my self
-
how much is it sped up by? what scale?
-
some people just want to watch the world turn.
-
you welcome...my pleasure, of course all the planets apart from Venus and Uranus, turn from west to east in an anti clockwise rotation. the direction in Astronomy is count by viewing above North Pole of any object. as for Venus is tipped over probably by a giant impact early in its history so is rotating the wrong way from east to west, there the Sun rises in the west and sets in the east. Uranus however is tipped on its side by 98 degress so the poles are facing the Sun not the equator !
-
thanks for this very useful info in your animation - I'm animating a CGI globe myself and I had the earth turning the wrong way... which means I would have looked like an idiot when I showed to my client :)
-
@KurdstanPlanetarium swpas swpas
-
@kirkuki88 her bijit u serkewtubet :)
-
Me like your video just because you are a Kurdish :)) bji Kurd
-
@imegatrone you welcome...glad you found it useful
-
@Melehete you welcome...happy you enjoyed it and fount it useful
-
Steady I Really Like This Video This provides the absolute reference for the determination of universal time, precession, and nutation.
-
@NganaJHone you welcome...glad you enjoyed it
-
@12pointdeath why not look at my latest Earth Rotaion "Cloud Covered" here as video response, and see what improvement I made, you can see even the clouds rotates separately than Earth itself...
-
@KurdstanPlanetarium Fine.
-
@AndyHarglesis I can slow it down, just the way it works in Nature, but then you have to keep vigil and see it turning seconds by seconds, how about that?
0m 0sLenght
63Rating