<p>They aren't.  To first order, airborne objects are moving with the Earth because they were moving when on the ground.  However, what they retain is their angular speed, and since the circumference increases with altitude, an object that doesn't accelerate appropriately will appear from the ground to fall behind to the West (the Earth is rotating to the East).  This is a well-known phenomenon whose magnitude is latitude-dependent, falling to zero at the poles. </p>

CC BY-SA 3.0
2016-10-10T13:57:18.063Z
so if even I accelerate I will only be staying at the same spot on the ground as I go further up in the atmosphere?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-10T14:29:04.790Z
@MuhammadUsmanQureshi If you accelerate such that you match the angular speed of the earth's rotation then you'll remain over the launch spot.
Carl Witthoft
CC BY-SA 3.0
2016-10-10T14:38:30.490Z
so if I have to go in the opposite direction that is east to west I just have to remain at o acceleration , since im not accelerating ill be going westward???? meaning im going at a constant speed towards east but I end up in a place west of my current position???????? that cant be true man
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-10T13:24:18.817Z
2016-10-10T13:24:18.817Z
Carl Witthoft
<p>When something is flying through the air, it keeps moving along with the Earth because it was already moving that way to begin with.  Remember that according to <a href="https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton.27s_1st_Law" rel="nofollow">Newton's First Law</a>, things will keep moving in the same direction unless an outside force acts on them.  So when a bird, plane, or helicopter is on the ground, they are rotating along with the Earth.  In the rotating reference frame of the Earth, they are stationary.  From an external frame which sees the Earth as rotating, the object will be rotating in the same way.  Now, when a plane takes off, it is changing its motion relative to the ground.  In that reference frame, it begins moving.  However, from our external reference frame, it was already moving.  So its just changing its already non-zero velocity.</p>

CC BY-SA 3.0
2016-10-09T19:12:35.527Z
That frame of reference thing i understand. But its not about take off, let me put it another way. Im in mid air in a helicopter and im just hovering 200m above the ground, going neither east nor west nor south nor north. Yet when i look down i cant see the earth rotate. Is it because gravity is pulling me with the rotation?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-09T20:05:08.367Z
@MuhammadUsmanQureshi no it's not gravity cause gravity doesn't pull you sideways.   Your momentum is already moving in that direction and the Earth's atmosphere moves largely with the Earth's rotation so it would take a great deal of work (acceleration or deceleration as you prefer) to slow down to the point where you saw the Earth rotating below you and you'd have to fight a great deal of wind resistance.   Everything is already moving with the Earth's rotation, so it takes a lot of energy and work to "stop" rotating with it.
userLTK
CC BY-SA 3.0
2016-10-10T04:40:09.797Z
If my momentum is moving with earth's rotation then if i want to go in the other direction i will also need a lot of force to move even a single mile in that direction if im not mistaken? But that is not the case so why is that?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-10T04:43:11.837Z
No, because the entire Earth is moving in that direction.  So from an external reference frame, it will look like you just slow down a little and allow the Earth to rotate underneath you.
Phiteros
CC BY-SA 3.0
2016-10-10T04:43:12.257Z
The earth rotates from west to east right, so tell me if im wrong, but if we talk about momentum while in the air and i want to go 10 miles to the west of my current position it will take alot more force as compared to going 10 miles east. But that is not the case, why?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-10T05:49:14.980Z
The "medium" of air is moving with the floating object and with the surface of the Earth. (for the most part, there are some prevailing winds that are slightly different than surface rotation on average).   Because the relative velocity is relative to the Air, which is similar to the surface, moving 10 miles East or 10 miles West is very similar.   The Earth's rotation has very little effect.   Now if the Earth was rotating at close to escape velocity (a bit over 10 times faster), then you might detect a slight difference moving East vs. moving West cause you'd be close to escape velocity.
userLTK
CC BY-SA 3.0
2016-10-10T14:01:12.570Z
I get that the atmosphere surrounding the planet is rotating with the earth, but with the air molecules going west to east wouldn't there be friction going against those trying to go west and help those who are going with those molecules towards east? cause speed of rotation is what more than 1k miles/h. theoretically shouldn't this be true at such a high speed? I mean at large distances like if u want to go to rio from Siberia?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-11T18:55:56.533Z
Hi @MuhammadUsmanQureshi.  Think about the oceans.  They entirely rotate with the Earth - right?  They do not in the slightest "fall backwards" to the west - am I right?  The atmosphere is **just the same**.  It's no big deal, really.
Fattie
CC BY-SA 3.0
2016-10-11T18:57:00.397Z
Or look at it this way.  Say you are **just standing there**.  Do you feel a force pushing you Westwards?  **No**.  so if you were suddenly one inch off the ground, would you suddenly feel a force pulling you westwards? No.
Fattie
CC BY-SA 3.0
2016-10-12T17:06:16.663Z
For the second time im not talking about the frame of reference, im not outside the planet. Im on the planet earth in mid air. Let me ask again, as i take off the ground i carry my momentum of the rotation of earth but i dont feel that thats for someone observing from outside thats fine. Also the whole atmosphere is moving cause of such a big rock is rotating, there fore i still dont feel the earth rotate under me. Now if i have to go opposite to the rotation, wouldn't the air molecules hinder my movement as opposed to helping me going with the rotation?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-12T17:09:22.383Z
@joe blow, the case with the oceans is different. But when im in mid air  in a helicopter im still with the atmosphere, but infact we are both moving with the rotation so when i want to go frwd thats fine if i want to go westward the atmospheric molecules should produce friction theoretically cause im no laonger in touch with ground? Am i right sri
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-12T17:10:19.583Z
Cause when im on the ground gravity is pulling me with it
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-12T17:22:09.463Z
@MuhammadUsmanQureshi The case of the ocean and the atmosphere is the same.  The atmosphere is rotating along with the Earth, at the exact same rate.  So if you are standing on the Earth, you are at rest relative to the air around you.  Even if you jump off the ground or fly into the air, the air is still not moving relative to you.  So it doesn't really help or hinder you, no matter which way you move.
Phiteros
CC BY-SA 3.0
2016-10-12T17:27:00.733Z
@phirores i get that the air around me is still relative to me. But when im in mid air the movement of air molecules should have some effect if i want to go against there movement  cause im no more in touch with the ground? On the ground the gravity helps me so dont feel anything going either way but once in the air gravity wont help me with that
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-12T17:29:52.980Z
Think about it this way.  Imagine you're on a train that's moving.  Another train pulls up alongside you and matches your speed.  You then step from your train across to the other train.  When this happens, you don't feel any kind of force, and you don't have to fight against the train's motion, because you're moving at the same rate as it.  It's the exact same principle.
Phiteros
CC BY-SA 3.0
2016-10-12T18:24:02.043Z
This really has absolutely no connection to astronomy.  It's just a basic misunderstanding about relative motion.
Fattie
CC BY-SA 3.0
2016-10-12T18:27:16.627Z
*"Cause when im on the ground gravity is pulling me with it"* that's not correct.  Imagine a large chunk of the earth (like a mountain).  Is the Earth "pulling it along"?  Not at all.  It is *already in motion* and just keeps going. Same with "your body".  Imagine a large section of the Earth (about 1/4 of it). Is the rest of the Earth "pulling it along"?  Not at all - it is very simply "in motion" and ***just keeps going***.  No difference than if you shoot a gun out in space, the bullet will just *keep going* forever.
Fattie
CC BY-SA 3.0
2016-10-12T18:28:49.713Z
Consider the Earth going around the Sun.  Do you think the Sun (or something else) is "pulling it around"?  Nothing is "pulling it around". It just **keeps going**.  This is the basic concept of Newtonian physics - momentum; the most fundamental idea of physics.  Cheers!
Fattie
CC BY-SA 3.0
2016-10-09T18:16:08.603Z
2016-10-09T18:16:08.603Z
Phiteros
<p>When a bird is flying or when a copter is hovering or a plane is flying what force is making them rotate with the earth beneath them?</p>

CC BY-SA 3.0
2016-10-11T10:55:38.553Z
Why is this one on the astronomy site?
Fattie
CC BY-SA 3.0
2016-10-11T18:26:14.507Z
A question related to the earth's rotation, you tell me where should i post it then sir?
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-11T18:51:58.787Z
Hi, I guess just the physics site?  http://physics.stackexchange.com/
Fattie
CC BY-SA 3.0
2016-10-12T19:45:12.350Z
@MuhammadUsmanQureshi In this case I agree with Joe, this is really not an astronomy question.
called2voyage
CC BY-SA 3.0
2016-10-12T19:47:15.267Z
Already answered at Physics (http://physics.stackexchange.com/questions/263399/air-flight-and-earths-rotation). I'm going to close this one.
called2voyage
CC BY-SA 3.0
2016-10-12T19:47:27.850Z
Yeah i guess may be u r right. Ok i'll post it there then thanx Joe
Muhammad Usman Qureshi
CC BY-SA 3.0
2016-10-12T19:48:10.340Z
@MuhammadUsmanQureshi Don't post it there until you read the question I linked and see if it answers yours. Otherwise it might get closed as a duplicate over there.
called2voyage
CC BY-SA 3.0
2016-10-12T19:48:45.413Z
Yup i read the rules ghanx
Muhammad Usman Qureshi
<rotation>
What makes a flying object keep moving with the Earth's rotation?
Muhammad Usman Qureshi
# What makes a flying object keep moving with the Earth's rotation?

(Asked by: username_0 on 2016-10-09)

When a bird is flying or when a copter is hovering or a plane is flying what force is making them rotate with the earth beneath them?

**Tags:** rotation
> **Comments:**
> **username_1**: Why is this one on the astronomy site?  
> **username_0**: A question related to the earth's rotation, you tell me where should i post it then sir?  
> **username_1**: Hi, I guess just the physics site?  http://physics.stackexchange.com/  
> **username_2**: @MuhammadUsmanQureshi In this case I agree with Joe, this is really not an astronomy question.  
> **username_2**: Already answered at Physics (http://physics.stackexchange.com/questions/263399/air-flight-and-earths-rotation). I'm going to close this one.  
> **username_0**: Yeah i guess may be u r right. Ok i'll post it there then thanx Joe  
> **username_2**: @MuhammadUsmanQureshi Don't post it there until you read the question I linked and see if it answers yours. Otherwise it might get closed as a duplicate over there.  
> **username_0**: Yup i read the rules ghanx  

---

## 2 answers

### Answer by username_3 on 2016-10-10. Score: 1

They aren't. To first order, airborne objects are moving with the Earth because they were moving when on the ground. However, what they retain is their angular speed, and since the circumference increases with altitude, an object that doesn't accelerate appropriately will appear from the ground to fall behind to the West (the Earth is rotating to the East). This is a well-known phenomenon whose magnitude is latitude-dependent, falling to zero at the poles.

> **Comments:**
> **username_0**: so if even I accelerate I will only be staying at the same spot on the ground as I go further up in the atmosphere?  
> **username_3**: @MuhammadUsmanQureshi If you accelerate such that you match the angular speed of the earth's rotation then you'll remain over the launch spot.  
> **username_0**: so if I have to go in the opposite direction that is east to west I just have to remain at o acceleration , since im not accelerating ill be going westward???? meaning im going at a constant speed towards east but I end up in a place west of my current position???????? that cant be true man  

---

### Answer by username_4 on 2016-10-09. Score: 0

When something is flying through the air, it keeps moving along with the Earth because it was already moving that way to begin with. Remember that according to [Newton's First Law](https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton.27s_1st_Law), things will keep moving in the same direction unless an outside force acts on them. So when a bird, plane, or helicopter is on the ground, they are rotating along with the Earth. In the rotating reference frame of the Earth, they are stationary. From an external frame which sees the Earth as rotating, the object will be rotating in the same way. Now, when a plane takes off, it is changing its motion relative to the ground. In that reference frame, it begins moving. However, from our external reference frame, it was already moving. So its just changing its already non-zero velocity.

> **Comments:**
> **username_0**: That frame of reference thing i understand. But its not about take off, let me put it another way. Im in mid air in a helicopter and im just hovering 200m above the ground, going neither east nor west nor south nor north. Yet when i look down i cant see the earth rotate. Is it because gravity is pulling me with the rotation?  
> **username_5**: @MuhammadUsmanQureshi no it's not gravity cause gravity doesn't pull you sideways.   Your momentum is already moving in that direction and the Earth's atmosphere moves largely with the Earth's rotation so it would take a great deal of work (acceleration or deceleration as you prefer) to slow down to the point where you saw the Earth rotating below you and you'd have to fight a great deal of wind resistance.   Everything is already moving with the Earth's rotation, so it takes a lot of energy and work to "stop" rotating with it.  
> **username_0**: If my momentum is moving with earth's rotation then if i want to go in the other direction i will also need a lot of force to move even a single mile in that direction if im not mistaken? But that is not the case so why is that?  
> **username_4**: No, because the entire Earth is moving in that direction.  So from an external reference frame, it will look like you just slow down a little and allow the Earth to rotate underneath you.  
> **username_0**: The earth rotates from west to east right, so tell me if im wrong, but if we talk about momentum while in the air and i want to go 10 miles to the west of my current position it will take alot more force as compared to going 10 miles east. But that is not the case, why?  
> **username_5**: The "medium" of air is moving with the floating object and with the surface of the Earth. (for the most part, there are some prevailing winds that are slightly different than surface rotation on average).   Because the relative velocity is relative to the Air, which is similar to the surface, moving 10 miles East or 10 miles West is very similar.   The Earth's rotation has very little effect.   Now if the Earth was rotating at close to escape velocity (a bit over 10 times faster), then you might detect a slight difference moving East vs. moving West cause you'd be close to escape velocity.  
> **username_0**: I get that the atmosphere surrounding the planet is rotating with the earth, but with the air molecules going west to east wouldn't there be friction going against those trying to go west and help those who are going with those molecules towards east? cause speed of rotation is what more than 1k miles/h. theoretically shouldn't this be true at such a high speed? I mean at large distances like if u want to go to rio from Siberia?  
> **username_1**: Hi @MuhammadUsmanQureshi.  Think about the oceans.  They entirely rotate with the Earth - right?  They do not in the slightest "fall backwards" to the west - am I right?  The atmosphere is **just the same**.  It's no big deal, really.  
> **username_1**: Or look at it this way.  Say you are **just standing there**.  Do you feel a force pushing you Westwards?  **No**.  so if you were suddenly one inch off the ground, would you suddenly feel a force pulling you westwards? No.  
> **username_0**: For the second time im not talking about the frame of reference, im not outside the planet. Im on the planet earth in mid air. Let me ask again, as i take off the ground i carry my momentum of the rotation of earth but i dont feel that thats for someone observing from outside thats fine. Also the whole atmosphere is moving cause of such a big rock is rotating, there fore i still dont feel the earth rotate under me. Now if i have to go opposite to the rotation, wouldn't the air molecules hinder my movement as opposed to helping me going with the rotation?  
> **username_0**: @joe blow, the case with the oceans is different. But when im in mid air  in a helicopter im still with the atmosphere, but infact we are both moving with the rotation so when i want to go frwd thats fine if i want to go westward the atmospheric molecules should produce friction theoretically cause im no laonger in touch with ground? Am i right sri  
> **username_0**: Cause when im on the ground gravity is pulling me with it  
> **username_4**: @MuhammadUsmanQureshi The case of the ocean and the atmosphere is the same.  The atmosphere is rotating along with the Earth, at the exact same rate.  So if you are standing on the Earth, you are at rest relative to the air around you.  Even if you jump off the ground or fly into the air, the air is still not moving relative to you.  So it doesn't really help or hinder you, no matter which way you move.  
> **username_0**: @phirores i get that the air around me is still relative to me. But when im in mid air the movement of air molecules should have some effect if i want to go against there movement  cause im no more in touch with the ground? On the ground the gravity helps me so dont feel anything going either way but once in the air gravity wont help me with that  
> **username_4**: Think about it this way.  Imagine you're on a train that's moving.  Another train pulls up alongside you and matches your speed.  You then step from your train across to the other train.  When this happens, you don't feel any kind of force, and you don't have to fight against the train's motion, because you're moving at the same rate as it.  It's the exact same principle.  
> **username_1**: This really has absolutely no connection to astronomy.  It's just a basic misunderstanding about relative motion.  
> **username_1**: *"Cause when im on the ground gravity is pulling me with it"* that's not correct.  Imagine a large chunk of the earth (like a mountain).  Is the Earth "pulling it along"?  Not at all.  It is *already in motion* and just keeps going. Same with "your body".  Imagine a large section of the Earth (about 1/4 of it). Is the rest of the Earth "pulling it along"?  Not at all - it is very simply "in motion" and ***just keeps going***.  No difference than if you shoot a gun out in space, the bullet will just *keep going* forever.  
> **username_1**: Consider the Earth going around the Sun.  Do you think the Sun (or something else) is "pulling it around"?  Nothing is "pulling it around". It just **keeps going**.  This is the basic concept of Newtonian physics - momentum; the most fundamental idea of physics.  Cheers!  

---

