# Thread: Earth speed and Plane travel?

1. My Question
I have been trying to find an answer with no luck.

It takes 10 hours to fly from lets say New York to London and back.
The earth spins counter clockwise at 1000 mph
Now you take a plane from California to New York it takes lets just say 4 hours and 4 hours back or (return) with out time changes..
Now a plane goes 500 mph from California to New York .. So at 500 mph how does the plane catch New York if the earth spins a 1000 mph and when you travel from New York to California with the earth rotating towards you ,, You should get there in no time and you should actually meet in the middle..
If you say well its gravitational then when asteroids pass by why don't they stay in one place like the moon isn't the moon held in place by the earths gravitational pull and the asteroid are a lot smaller.
2nd If i could put a car in a balloon and let it float in the air and no wind blows it just sits lets say i released it in Kansas at 1000 mph the earth spins so California should be under in no time. I'm asking this because no one can answer my question.

2. Originally Posted by th1nkeR
So at 500 mph how does the plane catch New York if the earth spins a 1000 mph and when you travel from New York to California with the earth rotating towards you ,, You should get there in no time and you should actually meet in the middle..
The plane flies at 500mph wrt THE EARTH SURFACE.
The Earth rotates at 1000mph wrt ITS AXIS.
Two very different reference frames, that's how.

3. Originally Posted by th1nkeR
My Question
I have been trying to find an answer with no luck.

It takes 10 hours to fly from lets say New York to London and back.
The earth spins counter clockwise at 1000 mph
Now you take a plane from California to New York it takes lets just say 4 hours and 4 hours back or (return) with out time changes..
Now a plane goes 500 mph from California to New York .. So at 500 mph how does the plane catch New York if the earth spins a 1000 mph and when you travel from New York to California with the earth rotating towards you ,, You should get there in no time and you should actually meet in the middle..
If you say well its gravitational then when asteroids pass by why don't they stay in one place like the moon isn't the moon held in place by the earths gravitational pull and the asteroid are a lot smaller.
2nd If i could put a car in a balloon and let it float in the air and no wind blows it just sits lets say i released it in Kansas at 1000 mph the earth spins so California should be under in no time. I'm asking this because no one can answer my question.
Planes fly relative to the air. So if a plane is flying 500 mph, that is its air speed. It ground speed can be different is the air it is flying through itself is moving relative to the ground, like when there is a wind. So while the Earth's ground speed at the equator is 1000 mph relative to the Earth's axis, the air at the equator shares this same speed. For your balloon to reach California in hardly any time, the air in which it is floating would have to be "standing still" while the ground under it moved away at 100's of miles per hour(since Kansas is not on the Equator, the speed of the surface there relative to the axis will not be as large as it is at the equator.) But that means that you, standing on the ground would be fighting a several hundred mile an hour wind.

So what does the Air rotate with the Earth? it is basically dragged by the Earth. Imagine you started with the Earth rotating and the atmosphere not doing so. The ground would be "rubbing up" against the air touching it, this would in turn transfer motion to this lowest layer. This lower layer would transfer motion to the air just above it, and so on and so on until the whole atmosphere will eventually share in the Earth's rotation like it does now. Gravity comes in through the fact that it is what causes the air to hug the ground.

Now this is not to say that the air in held totally in place relative to the ground, after all, we do get winds. These are driven by the Sun. because the surface the Earth is not heated evenly, this causes up drafts and down draft in the air which displace the sir from one spot to another. This combined with the unevenness of the Earth's surface and its rotation create complex wind patterns. Since the Sun keeps pumping energy into these winds they never die off completely.

As far as the Moon goes, it is not "held in place", it is in orbit, traveling in a large nearly circular path around the Earth. What causes this orbit is a balance between its speed and Earth's gravity. If it traveled ~40% faster the Earth could not hold on to it and it would fly off into space. If it traveled too much slowly, gravity would pull it into the Earth. The range of speeds it can have and still stay in orbit if fairly large. Small differences in it speed would change the shape of the orbit, but that is all.

Asteroids fly by the Earth because they are moving too fast to be kept in an orbit around the Earth. They may start out moving relatively slow when they are far away, but as they get closer they speed up. Earth's gravity is pulling them towards it, and they pick up speed. (just like when you drop a rock and it falls faster and faster the farther it falls. So by the time they reach their closest point to the Earth, they are moving very fast relative to it. As they move away from the Earth, Earth's gravity pulling on them takes back the speed they gained inbound, and by the time they get far away again they are moving as slowly as they were before they started.

The exact path the asteroids take on their passage by the Earth falls into the realm of orbital mechanics ( as does the orbital motion of the Moon), and really falls outside of the scope of discussion when dealing with planes or balloons traveling with respect to the Earth while near the surface and in the atmosphere.

4. Originally Posted by AndrewC
The plane flies at 500mph wrt THE EARTH SURFACE.
The Earth rotates at 1000mph wrt ITS AXIS.
Two very different reference frames, that's how.

What speed would the earth be turning at the united states level. Would it be 300 mph less?

5. Originally Posted by th1nkeR
What speed would the earth be turning at the united states level. Would it be 300 mph less?
At Equator, the speed is 460 m/s
At US level , it is 400 m/s
See here

6. Originally Posted by th1nkeR
What speed would the earth be turning at the united states level. Would it be 300 mph less?
Take the cosine of the latitude for where you want and multiply that by the speed at the equator to get the speed at that latitude.
So for the continuous 48 states, it would range from ~110 miles per hour less in the Southernmost part to ~381 miles per hr less in the Northernmost part.

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