Rotating Question Curious About Astronomy? Ask an Astronomer

Why can't a plane fly slowly and let the Earth pass underneath?

This question has been bothering me for ages. When an airplane is airborne, why does it have to travel when it can just stay put at a safe distance above the earth, wait for the earth to rotate and then land when its destination landing nation is available . For example when traveling from India to Egypt, a plane can just get airborne and stay put at safe distance in the sky for about 6 hours during which time the Earth would have rotated and the plane would be above Egypt.

If you fly in the opposite direction that earth is spinning, basically flying against the spin, the earth is moving toward you with the spin at the speed of 1000 miles per hour. Assuming the plane is flying at 500 mph on its own, why are you not flying toward your destination at the speed of 1500mph?

The reason an airplane can't just idle and let the ground pass underneath is the same reason as why a ball dropped from a tall tower lands at the base of the tower and not next to it. A plane sitting on the ground is moving with the surface of the Earth, and while it appears to us to be at rest, it is actually moving at around 1,000 miles an hour (the exact value depends on your latitude). When it takes off, it still has speed from sitting on the ground. In order to fly east, the plane increases its speed relative to the surface of the Earth and begins to overtake it. Flying west it decreases its speed relative to the surface of the Earth, and the Earth slips by.

Here's a thought experiment. Imagine three moving walkways with a person standing on each one. Now let the person on the left walkway walk forward in the same direction of the walkway, the person in the center stays standing, and the person on the right walk backward in the opposite direction. All three people are moving in the direction of walkway is going, but the two people walking are moving in that direction more quickly and less quickly respectively than the person at rest. When the plane is sitting on the ground, it is like the person standing still on the moving walkway. The two people walking in same direction and opposite direction of the walkway are like the plane in air.

October 2010, Laura Spitler (more by Laura Spitler) (Like this Answer)

Still Curious?

Get More 'Curious?' with Our New PODCAST:

More questions about General Physics: Previous | Next

How to ask a question:

If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.

Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist

This page has been accessed 41022 times since October 2, 2010.
Last modified: August 19, 2011 11:52:58 AM

Legal questions? See our copyright, disclaimer and privacy policy.
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.

Warning: Your browser is misbehaving! This page might look ugly. (Details)