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Einstein realized that the overall distribution of matter would determine the metric tensor which indicates which frame is stationary with respect to rotation. Frame-dragging and conservation of gravitational angular momentum makes this into a true statement in the general theory in certain solutions.
Earth's rotation axis moves with respect to the fixed stars (inertial space); the components of this motion are precession and nutation. It also moves with respect to Earth's crust; this is called polar motion. Precession is a rotation of Earth's rotation axis, caused primarily by external torques from the gravity of the Sun, Moon and other bodies.
The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the Earth's rotation. Foucault followed up in 1852 with a gyroscope experiment to further demonstrate the Earth's rotation. Foucault pendulums today are popular displays in science museums and universities. [1]
We know Earth’s rotation on a cosmic scale, but seeing it close up requires quantum mechanics. Interferometry is the use of light waves, sound, etc., to identify changes in matter or motion.
It was once believed that the dipole, which comprises much of the Earth's magnetic field and is misaligned along the rotation axis by 11.3 degrees, was caused by permanent magnetization of the materials in the earth. This means that dynamo theory was originally used to explain the Sun's magnetic field in its relationship with that of the Earth.
14th century – Several European mathematicians and astronomers develop the theory of Earth's rotation including Nicole Oresme. Oresme also give logical reasoning, empirical evidence and mathematical proofs for his notion. [53] [54] 15th century – Nicholas of Cusa proposes that the Earth rotates on its axis in his book, On Learned Ignorance ...
Some important effects are Earth's nutation, rotation, atmospheric refraction, tectonic displacement and tidal waves. Another important effect is refraction of the radio waves by the solar corona . Fortunately, this effect has a characteristic spectrum , whereas gravitational distortion is independent of wavelength.
Changes during Earth's rotation have been searched for. Data between 2001 and 2002 was analyzed. Müller et al. [32] 2003: Two optical resonators constructed from crystalline sapphire, controlling the frequencies of two Nd:YAG lasers, are set at right angles within a helium cryostat. A frequency comparator measures the beat frequency of the ...