question: Why don’t we feel the Earth rotate if it’s spinning so fast?
comment: Frame of reference: we’re moving with it, and it isn’t accelerating or decelerating. Humans can’t sense relative motion.
passages: In the absence of external torques, the total angular momentum of Earth as a whole system must be constant. Internal torques are due to relative movements and mass redistribution of Earth's core, mantle, crust, oceans, atmosphere, and cryosphere. In order to keep the total angular momentum constant, a change of the angular momentum in one region must necessarily be balanced by angular momentum changes in the other regions.
   The various human body motion-sensors react to accelerations rather than steady-state motions and have thresholds below which they do not transmit signals to the brain (the latter explains why instruments are needed for safe cloud flying). Furthermore, impulses from the set of body motion sensors are processed by the brain in a timescale of milliseconds compared to longer time intervals for visual cues of the Outside World (OTW) to be registered by the brain. The body motion-sensors include the inner-ear sensors, (semicircular canals and otoliths, the "Vestibular sensors"), the muscle-and joint sensors, and sensors that register movements and pressures on body parts such as arms, legs and buttocks. 
   A convenient coordinate system in this situation is the inertial coordinate system that is co-moving with the center of mass of the Earth. Then the following is valid: objects that are at rest on the surface of the Earth, co-rotating with the Earth, are circling the Earth's axis, so they are in centripetal acceleration with respect to that inertial coordinate system.
   When the same object is weighed on the equator, the same two real forces act upon the object. However, the object is moving in a circular path as the Earth rotates and therefore experiencing a centripetal acceleration. When considered in an inertial frame (that is to say, one that is not rotating with the Earth), the non-zero acceleration means that force of gravity will not balance with the force from the spring. In order to have a net centripetal force, the magnitude of the restoring force of the spring must be less than the magnitude of force of gravity. Less restoring force in the spring is reflected on the scale as less weight — about 0.3% less at the equator than at the poles. In the Earth reference frame (in which the object being weighed is at rest), the object does not appear to be accelerating, however the two real forces, gravity and the force from the spring, are the same magnitude and do not balance. The centrifugal force must be included to make the sum of the forces be zero to match the apparent lack of acceleration.
   The globe was built with a scale of 1:1,000,000, on which one inch represents sixteen miles. As with most globes, it's mounted at a 23.5 degree angle, the same axial tilt as the Earth itself; thus the equator is diagonal to the floor. It uses a cantilever mount with two motors, and simulates one day's revolution and rotation every 18 minutes, though it is possible for the motors to fully rotate the globe in as little as one minute. 
   The "global terrestrial stilling" is not affecting in the same way the whole Earth's surface across both land and ocean surfaces. Spatially, increasing wind speed trends have been reported for some regions, in particular for high-latitudes, coastal and for ocean surfaces where different authors have evidenced an increased global trend of wind speed using satellite measurements in the last 30–40 years. Recent studies have shown a break in the negative tendency of terrestrial wind speeds, with a recent widespread recovery / strengthening of wind speed since around 2013. This creates uncertainty in understanding the phenomenon.
   In 1672 Jean Richer found the first evidence that gravity was not constant over the Earth (as it would be if the Earth were a sphere); he took a pendulum clock to Cayenne, French Guiana and found that it lost minutes per day compared to its rate at Paris. This indicated the acceleration of gravity was less at Cayenne than at Paris. Pendulum gravimeters began to be taken on voyages to remote parts of the world, and it was slowly discovered that gravity increases smoothly with increasing latitude, gravitational acceleration being about 0.5% greater at the poles than at the equator.
   Section::::Location.
  
  In humans, temperature sensation enters the spinal cord along the axons of Lissauer's tract that synapse on second order neurons in grey matter of the dorsal horn, one or two vertebral levels up. The axons of these second order neurons then decussate, joining the spinothalamic tract as they ascend to neurons in the ventral posterolateral nucleus of the thalamus.
   Section::::Other senses.
  
  Section::::Other senses.:Balance and acceleration.
  
  Balance, equilibrioception, or vestibular sense is the sense that allows an organism to sense body movement, direction, and acceleration, and to attain and maintain postural equilibrium and balance. The organ of equilibrioception is the vestibular labyrinthine system found in both of the inner ears. In technical terms, this organ is responsible for two senses of angular momentum acceleration and linear acceleration (which also senses gravity), but they are known together as equilibrioception.
   Humans, like all known things in the universe, are in constant motion; however, aside from obvious movements of the various external body parts and locomotion, humans are in motion in a variety of ways which are more difficult to perceive. Many of these "imperceptible motions" are only perceivable with the help of special tools and careful observation. The larger scales of imperceptible motions are difficult for humans to perceive for two reasons: Newton's laws of motion (particularly the third) which prevents the feeling of motion on a mass to which the observer is connected, and the lack of an obvious frame of reference which would allow individuals to easily see that they are moving. The smaller scales of these motions are too small to be detected conventionally with human senses.
   On the poles and on the equator the force of gravity and the normal force are exactly in opposite direction. At every other latitude the two are not exactly opposite, so there is a resultant force, that acts towards the Earth's axis. At every latitude there is precisely the amount of centripetal force that is necessary to maintain an even thickness of the atmospheric layer. (The solid Earth is ductile. Whenever the shape of the solid Earth is not entirely in equilibrium with its rate of rotation, then the shear stress deforms the solid Earth over a period of millions of years until the shear stress is resolved.)
   Humans can sense head tilting and linear acceleration even in dark environments because of the orientation of two groups of hair cell bundles on either side of the striola. Hair cells on opposite sides move with mirror symmetry, so when one side is moved, the other is inhibited. The opposing effects caused by a tilt of the head cause differential sensory inputs from the hair cell bundles allow humans to tell which way the head is tilting, Sensory information is then sent to the brain, which can respond with appropriate corrective actions to the nervous and muscular systems to ensure that balance and awareness are maintained.
   The other consequence of tidal acceleration is the deceleration of the rotation of Earth. The rotation of Earth is somewhat erratic on all time scales (from hours to centuries) due to various causes. The small tidal effect cannot be observed in a short period, but the cumulative effect on Earth's rotation as measured with a stable clock (ephemeris time, atomic time) of a shortfall of even a few milliseconds every day becomes readily noticeable in a few centuries. Since some event in the remote past, more days and hours have passed (as measured in full rotations of Earth) (Universal Time) than would be measured by stable clocks calibrated to the present, longer length of the day (ephemeris time). This is known as ΔT. Recent values can be obtained from the International Earth Rotation and Reference Systems Service (IERS). A table of the actual length of the day in the past few centuries is also available.
   Entrainment is a concept first identified by the Dutch physicist Christiaan Huygens in 1665 who discovered the phenomenon during an experiment with pendulum clocks: He set them each in motion and found that when he returned the next day, the sway of their pendulums had all synchronized.
   Section::::Equilibrium.
  
  Suppose the body is moving with a velocity formula_4 such that the centripetal and Coriolis (due to formula_12) forces on it are balanced. We then have
  
  where formula_14 is the radius of curvature of the path of object (defined by formula_15). Replacing formula_16, where formula_17 is the magnitude of the spin rate of the Earth, we obtain
   The idea of centrifugal force is closely related to the notion of absolute rotation. In 1707 the Irish bishop George Berkeley took issue with the notion of absolute space, declaring that "motion cannot be understood except in relation to our or some other body". In considering a solitary globe, all forms of motion, uniform and accelerated, are unobservable in an otherwise empty universe. 
   When this calculation is done for objects on the surface of the Earth, or aircraft that rotate with the Earth, one has to account for the fact that the Earth is rotating and the centrifugal acceleration has to be subtracted from this. For example, the equation above gives the acceleration at 9.820 m/s, when , and The centripetal radius is , and the centripetal time unit is approximately reduces this, for to 9.79379 m/s, which is closer to the observed value. 
  
  Section::::General relativity.
   Tonic muscles are much slower than twitch fibers in terms of time from stimulus to full activation, time to full relaxation upon cessation of stimuli, and maximal shortening velocity. These muscles are rarely found in mammals (only in the muscles moving the eye and in the middle ear), but are common in reptiles and amphibians.
  
  Section::::Tonic sensory receptors.
   The Earth's crust is the outer brittle layer of our planet, on average thick in continental areas. This moves up and down by ten centimeters during the time of 12 and 24 hours due to the attraction of Moon and Sun, and is accompanied by a local tilting of some parts in a billion of radians.
   BULLET::::- The Rapidly Adapting (RA) or Meissner corpuscle end-organ mechanoreceptor underlies the perception of flutter and slip on the skin. They have small receptive fields and produce transient responses to the onset and offset of stimulation.
  
  BULLET::::- The Pacinian corpuscle or Vater-Pacinian corpuscles or Lamellar corpuscles underlie the perception of high frequency vibration. They also produce transient responses, but have large receptive fields.
  
  Section::::Types.:Cutaneous.:By rate of adaptation.
   A classic argument against Earth motion is the lack of speed sensations of the Earth surface, though it moves, by the Earth's rotation, at about 1700 km/h at the equator. In this category there is a thought experiment in which a man is below decks on a ship and cannot tell whether the ship is docked or is moving smoothly through the water: he observes water dripping from a bottle, fish swimming in a tank, butterflies flying, and so on; and their behavior is just the same whether the ship is moving or not. This is a classic exposition of the Inertial frame of reference and refutes the objection that if we were moving hundreds of kilometres an hour as the Earth rotated, anything that one dropped would rapidly fall behind and drift to the west.
   equals about 166 Hz. This would be easy to notice. However, the pulsar is spinning at a quarter of the speed of light at the equator, and its radius is only three times more than its Schwarzschild radius. When such fast motion and such strong gravitational fields exist in a system, the simplified approach of separating gravitomagnetic and gravitoelectric forces can be applied only as a very rough approximation.
  
  Section::::Lack of invariance.
   For the Earth, formula_5 is estimated to be of order 10
  
  Dissipation is more significant, but a magnetic field is supported by motion in the liquid iron outer core. There are other bodies in the solar system that have working dynamos, e.g. Jupiter, Saturn, and Mercury, and others that do not, e.g. Mars, Venus and the Moon.
  
  The human length scale is very small so that typically formula_26. The generation of magnetic field by the motion of a conducting fluid has been achieved in only a handful of large experiments using mercury or liquid sodium.
  
  Section::::Bounds.
   The first large-capacity brushless battery torque wrench was invented in Germany in 2013.
  
  Before the brushless motor with micro electronics was introduced, the battery torque wrench was not as accurate as it could be.
  
  Because of the power limitations of the accurate motor, the tool has 2 speeds: one for speed, and one for power.
  
  Section::::Battery requirements.
   For the body to keep moving properly and with finesse, the nervous system has to have a constant input of sensory data coming from areas such as the muscles and joints. In order to receive a continuous stream of sensory data, the body has developed special sensory receptors called proprioceptors. Muscle spindles are a type of proprioceptor, and they are found inside the muscle itself. They lie parallel with the contractile fibers. This gives them the ability to monitor muscle length with precision.
  
  Section::::Types of sensory fibers.
  
presuppositions: People should be able to feel the rotation of the Earth because it is spinning fast.
corrections: People are rotating at the same speed as the Earth, and cannot sense relative motion.
raw_presuppositions: People should be able to feel the rotation of the Earth because it is spinning fast. People should be able to feel the rotation of the Earth because it is such a high speed.
raw_corrections: People are rotating at the same speed as the Earth, and cannot sense relative motion. People are rotating at the same speed as the Earth, and cannot sense relative motion.