So, if I build a highway from north pole towards equator and sit in a car, speed pretty fast towards it, I should feel force with the Earths rotation due to the different rotation speeds of this points. Which is basically 0 at north pole and 1000 mph on equator, so I should gradually pick up 1000mph of speed on my journey.

Why doesn't this happend with objects that are above the ground, for example, airplanes that fly throught atmosphere. The atmosphere itself is rotating with the Earth, therefore there should be the same difference in speed. Shouldn't airplanes and other objects gradually pickup speed because of the speed difference in atmosphere itself?

  • 2
    $\begingroup$ Why do you think they don't pick up speed? At the equator, you are doing 40,000 km/24 hours. Whether you are in the air, or on the ground. Because the plane moves relative to the air - and the air moves with the earth. If there was no atmosphere (e.g. for a satellite) a circumpolar orbit does indeed appear (from Earth's perspective) to change speed. Of course the satellite itself doesn't know and doesn't care... $\endgroup$
    – Floris
    May 27 '15 at 20:46
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    $\begingroup$ At the poles when the Coriolis effect is at its strongest, a 600 mph airplane would be accelerating at just under 0.02 m/s, which is about a 500th of gravity. It's something you could notice if you looked closely, but it's not anything you have to worry about. It's no different than flying the plane slightly tilted so it accelerates just a bit to one side. $\endgroup$
    – DanielLC
    May 28 '15 at 0:53
  • $\begingroup$ Doug Morris - Captain Air Canada says in short The Earth’s rotation does not affect travel time. $\endgroup$
    – user46925
    Feb 4 '16 at 19:38

Your intuition that there is no difference between airplanes and cars is correct. If you measure motion relative to a frame fixed to the stars, so not rotating, a point on the equator is traveling about 1000 mph. As you drive from the pole to the equator, you get that velocity, and so does an airplane. It is more common to use a reference frame that is fixed to and rotating with the earth. In that frame the equator is not moving and neither the plane nor the car will gain velocity by going to the equator.

  • $\begingroup$ So how does the difference between a car and airplane happen in real life? If I set course on airplane directly above the car on the on pole towards equator, the car will obviously arrive directly on the equator in straight line. The airplane is going to end in other place as we know. But if the car picks up velocity and so does airplane, where is the difference? I'm thinking something like the car is physically connected to the ground, so it can counteract this effect and airplane is not, so it gradually moves off course in small amounts. Maybe I'm wrong thought. Thank you for your answers $\endgroup$
    – pittacus
    May 27 '15 at 22:05
  • $\begingroup$ Neither the car nor the airplane move in a straight line. Both are affected by the environment (bumps, gusts, etc.) that require constant adjustments to maintain course. These adjustments overwhelm the Coriolis force over the trip. Both the road and the lower levels of the atmosphere are connected to the earth. A ballistic missile outside the atmosphere would behave differently. $\endgroup$
    – BowlOfRed
    May 27 '15 at 22:47
  • $\begingroup$ @pittacus: Why do you say the airplane is going to end in (an)other place? If the atmosphere rotates with the earth and there is no wind it will also follow a line of longitude. Yes, the car automatically corrects for Coriolis by friction of its tires. The airplane will have to correct as well, but it is rather small. $\endgroup$ May 28 '15 at 4:35
  • $\begingroup$ Yes, that's what I've been wondering about, the atmospehere is rotating with the earth, so the plane in the atmosphere is rotating with it as it flies, so the effect shouldn't be big. So I tihnk the higher you go, the more you have to compensate because the amtmosphere is getting thinner and therefore the effect is bigger. So theoretically, flying at very low level should have a very small effect on aircrafts path. $\endgroup$
    – pittacus
    May 28 '15 at 11:52
  • $\begingroup$ @pittacus: If instead of an airplane, you launched a rocket above the atmosphere, yes it would be in a different place when it reached the equator. In the airplane, the air mass it is traveling in gradually picks up speed as the plane goes south, so it would experience this as a slight force from the right, just as in the car. Any plane is constantly adjusting for wind, so it would not be noticed. $\endgroup$ May 28 '15 at 12:36

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