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i am having one doubt in earth's curvature.....this question may be dumb...

How much we need to travel on earth to feel the curvature of earth. hypothetical case: for ex we are building a vehicle which how much is the length of that vehicle to feel the earth's curvature....

one more question, what is the speed of the earth.....again hypothetical case, if we are travelling in aeroplane from one country to other, whether we can take earth's rotational speed(rotating around it's own axis), and aeroplane speeds as comparables and find the resultant speed?

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closed as off-topic by Eduardo Serra, Gerald, Donald.McLean Feb 19 '14 at 15:15



The question appears to be off-topic in the sense of the site, since it is only related to Earth, not to other celestial objects or phenomena. –  Gerald Feb 18 '14 at 23:41

2 Answers 2

About curvature, you can see it. Just look at a ship some hundred meters away: you'll notice if you are careful that you can not see where the ship touches water.

You can see at http://mathcentral.uregina.ca/qq/database/QQ.09.97/dyck2.html that the curvature is 8 inches per mile.

On the other hand, about rotation, planes do actually take advantage of earth rotation, but not directly. This was answered in http://physics.stackexchange.com/questions/16390/does-the-rotation-of-the-earth-dramatically-affect-airplane-flight-time

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Earth's rotation doesn't help airplanes much: the air is almost stationary with respect to the earth and airplanes move relative to the air. Suppose a hot air balloon. Air is dragged along with the rotation of earth, so the balloon will almost be stationary. (Ok, it moves, but only slowly.) So whether the plane travels east or west for 1000 km, it has to travel 1000 km against air which is 900 km/h slower.

There is a meteorological effect that planes can use, though. The jet stream is a channel of very high speed winds at high altitude.

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Planes traveling east, for instance from the US west coast to the east coast, or from America to Europe, take advantage of this jet stream to save fuel. Note that the jet stream isn't anywhere as fast as the earth's rotation. At 50 degrees north the earth's rotation is about 1000 km/h, while the jet stream is about 200 km/h.

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