Earth Rotation Slowing down

Effects of moon's gravity
Because the Moon's mass is a considerable fraction of that of the Earth (about 1:81), the two bodies can be regarded as a double planet system, rather than as a planet with a satellite. The plane of the Moon's orbit around the Earth lies close to the plane of the Earth's orbit around the Sun (the ecliptic), rather than in the plane perpendicular to the axis of rotation of the Earth (the equator) as is usually the case with planetary satellites. The mass of the Moon is sufficiently large, and it is sufficiently close, to raise tides in the matter of the Earth. In particular, the water of the oceans bulges out along both ends of an axis passing through the centers of the Earth and Moon. The average tidal bulge closely follows the Moon in its orbit, and the Earth rotates under this tidal bulge in just over a day. However, the rotation drags the position of the tidal bulge ahead of the position directly under the Moon. As a consequence, there exists a substantial amount of mass in the bulge that is offset from the line through the centers of the Earth and Moon. Because of this offset, a portion of the gravitational pull between Earth's tidal bulges and the Moon is perpendicular to the Earth-Moon line, i.e. there exists a torque between the Earth and the Moon. This boosts the Moon in its orbit, and decelerates the rotation of the Earth.
So the result is that the mean solar day, which is nominally 86400 seconds long, is actually getting longer when measured in SI seconds with stable atomic clocks. (The SI second, when adopted, was already a little shorter than the current value of the second of mean solar time.[9]) The small difference accumulates every day, which leads to an increasing difference between our clock time (Universal Time) on the one hand, and Atomic Time and Ephemeris Time on the other hand: see ΔT. This makes it necessary to insert a leap second at irregular intervals.
If other effects were ignored, tidal acceleration would continue until the rotational period of the Earth matched the orbital period of the Moon. At that time, the Moon would always be overhead of a single fixed place on Earth. Such a situation already exists in the Pluto-Charon system. However, the slowdown of the Earth's rotation is not occurring fast enough for the rotation to lengthen to a month before other effects make this irrelevant: About 2.1 billion years from now, the continual increase of the Sun's radiation will cause the Earth's oceans to vaporize, removing the bulk of the tidal friction and acceleration. Even without this, the slowdown to a month-long day would still not have been completed by 4.5 billion years from now when the Sun will evolve into a red giant and possibly destroy both the Earth and Moon. (Tidal acceleration is also moving the Earth outward from the Sun, but it is unknown whether it will be enough to save it from destruction.)
Tidal acceleration is one of the few examples in the dynamics of the solar system of a so-called secular perturbation of an orbit, i.e. a perturbation that continuously increases with time and is not periodic. Up to a high order of approximation, mutual gravitational perturbations between major or minor planets only cause periodic variations in their orbits, that is, parameters oscillate between maximum and minimum values. The tidal effect gives rise to a quadratic term in the equations, which leads to unbounded growth. In the mathematical theories of the planetary orbits that form the basis of ephemerides, quadratic and higher order secular terms do occur, but these are mostly Taylor expansions of very long time periodic terms. The reason that tidal effects are different is that unlike distant gravitational perturbations, friction is an essential part of tidal acceleration, and leads to permanent loss of energy from the dynamical system in the form of heat. In other words, we do not have a Hamiltonian system here.

Category:

Science & Technology

Tags:

• Earth rotation
• tidal forces
• tides
• lunar tidal forces
• decelaration of Earth rotation
• Earth
• Moon
• NASA
• ESA
• Kurd
• Kurdistan

[FTSx21]

So there will be a time where a day is going to be 72 hours long? WTF?!?

[KurdstanPlanetarium]

@FTSx21 No unfortunately thats is not possible for many reasons; first to calcuate the time needed to reach 72 hours:

72 - 24 = 48 hrs, we know from this video every 2 hrs = 400 Million years

so 48 / 2 = 24 , 24 * 400000000 = 9.6 Billion years

now in another 5 billion years the Sun's nuclear fuel force it into a Red Giant and engulf the whole Earth & Beyond, so the Ocean waters boiled off into space. no water then no tides to lengthen day times...the other reason in next comment !!

[KurdstanPlanetarium]

@KurdstanPlanetarium to continue:

The Moon receding from Earth by as much as 1 cm per year, thats about 10 Km in 1 million years. As the Moon recedes its gravitational pull becomes weaker and so its effect on the Ocean Tides will be less , the result the lengthening of the day times as shown here is getting less and less over time..

the Moon might even escape Earth pull of Gravity one day and head off to Space, so no more Tides !!

[KurdstanPlanetarium]

@KurdstanPlanetarium to say No Tides at all, that's abit of exageration of course, there will be still the Sun around that contribute to the tides withe Moon, but as that of the Moon is exceeding that of the Sun, so the Tides will be very weak indeed, maybe less than half of its values now !!

[straightcleaner]

Yeah well how long are the days when the Earth does a total flip flop or comes to an end in 2012?lol

[KurdstanPlanetarium]

@straightcleaner The Earth does not end in 2012 mark my word, there is nothing astronomical about end of the world, so be rest asure...no one can fortell the end of the world that existed for billions of years, though Astronomer can predict the life cycle of stars like our sun hence life on Earth depends on it..December 2012 is the end of the Cylce in Mayan Calender, that has nothing to do with out there...you see calenders designed to regulate time not the other way round !!

[AlYassou3Rabbi]

Ask me in 400,000,000 years if I care.

[stildiko]

Very interesting!

[hitmann34]

@BobMartin5613 yes i have watched those videos and it honestly make a lot more logical sense, I just don't think those kind of questions are asked when you go through school. To think that the planets are the size they are and will always be this size goes against science completely especially what we were taught about it!If we think the planets have always been the size they are and still remain the same today we must believe in Jesus creating them,and we know that didnt happen!

[BobMartin5613]

@hitmann34 I agree with you about that video showing how the solar system actually moves. It's a more accurate way of looking at it.

Did you see the Earth is Growing videos? It makes more sense than the traditional view. It's simpler, and science (as I've studied it) prefers the simple explanation to the complex one. Occam's Razor.

[BobMartin5613]

@KurdstanPlanetarium Not questioning your standing as a scientist, but the evidence shows that the Sun isn't a giant nuclear reactor. It's an electromagnetic receiver, processer, transmitter. It has an iron surface. Plasma cosmology is a more accurate model, but is resisted by the establishment.

Gravity isn't what we've been taught. If it were, the Moon wouldn't be moving away from the Earth, and the Earth moving away from the Sun.

Tides are caused by Earth's wobble. Not by the Moon.

[12chetrix]

dont u understand? the mayans got tired of writing and writing! so they said- okay we gonna make 2012 the las days! yeah! we gonna freak them out!

[hitmann34]

This would mean that the Earth is not growing in a linear fashion and it would also mean that the Earth has more or less the same speed of spinning on its own axis, just back millions of years ago its diameter was smaller and slowly over time its diameter is increasing making days longer. Just recently watched a video showing the solar system in a 3D Model as it travels through space which is a lot more logical way of thinking about it the solar system and how we interact with space around us!