Hovering and Earth's rotation

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wurf

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A person hovering in a helicopter doesn't perceive the Earth rotating underneath him at 1,000 m.p.h or so. Is this because the Earth's atmosphere rotates with the terra firma? So hypothetically, if you were in a helicopter and, with no lateral movement, could hover perfectly above the ground exactly over the north or south pole, the helicopter would pivot around, and an object visible on the earth in front of you would remain in front of you?<br /><br /> Does gravity somehow keep a hovering object within the atmosphere geosynchronous, so to speak? Gravity pulls all matter towards the earth's core. To keep the object over a fixed point on the earth's surface, it seems it would require some kind of "sideways" pull, not exactly in the direction of the core. I mean if you were hovering over the city of Quito, Ecuador, and Quito is moving east underneath, how is the helicopter being "pulled" east? I'm just a layman so forgive any stupidity contained in the above, lol, but I can't figure it out.

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Mee_n_Mac

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In a word ... inertia. Or more precisely conservation of angular momentum. On an airless world if you supplied a force to counter gravity and hovered 10 ft off the ground, you'd still have the angular momentum you had on the ground. But because of your increased radius from the center of rotation, your rate would slow. At 10 ft it would be pretty small but eventually you'd see the surface move under you. Here on Earth because the air is also moving with the surface, a force will be exerted to reduce the small effect above rendering it imperceptable (at small altitiudes). <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

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