# Question for the scientists among you.

#### jamoor

Soldato
Yes I have tried googling this one...

If a plane takes off in London and flies directly south and goes all the way around the globe and aims to land back in london without changing heading, will it land in a different place as the earth is spinning underneath it?

#### PermaBanned

Soldato
It isn't as simple as saying that the Earth spins beneath the plane because the plane isn't in orbit, it's still attracted to the centre of mass. If you jump the Earth isn't moving beneath you. But then it's not quite as simple as saying that it's the same as it being on the surface either, because the atmosphere demonstrates fluid motion above the surface.

#### Gzero

Associate
Yes I have tried googling this one...

If a plane takes off in London and flies directly south and goes all the way around the globe and aims to land back in london without changing heading, will it land in a different place as the earth is spinning underneath it?

You are forgetting trim, so no, potentially the plane would land in the same place thanks to all the gizmos and tools we have spent decades developing to ensure the plane finds the runway.

In an ideal test, momentum is conserved, you go up and you come back down again in the same spot (get a trampoline).

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#### olivier renault

Soldato
discounting air friction, I'll say you will land in the same spot. You also rotate at the same speed as the earth when you take off, and you'll still be when you land.

#### Castiel

Permabanned
The plane isn't outside of the influence of the Earth, so not, as the Earth Spins so the plane remains on the same heading relative to the Earth. Just like when you jump up and down on the spot.

#### PermaBanned

Soldato
There's also the possibility that if you were 'in orbit', you could land at the same spot as long as your orbit was synchronous with the rotational period of the Earth. Say, for every one rotation you complete one orbit. Or two, or three, or any integer. But not half.

#### Bear

Soldato
Thinking about it, you must land in the same place as the rotation can't effect your journey, if it did then you couldn't fly west unless you were close to the poles. The earth rotates roughly at 1000mph and a plane cruises at about 500mph. If the rotation effected your flight then flying east would mean you could do a combined speed of 1500mph but if you flew to west then you wouldnt be able to get there as you would technically be going backwards. Obviously this is based on being at the equator.

This is obviously not the case so the rotation can't be a factor.

#### Selekt0r

Associate
Surely it depends on whether the plane takes off using a treadmill or not...?

#### MeEsH BaKkA

Soldato
The plane isn't outside of the influence of the Earth, so not, as the Earth Spins so the plane remains on the same heading relative to the Earth. Just like when you jump up and down on the spot.

As an ex-soldier I would have thought you would have known the coriolis effect, Im 99% sure it have the same effect on planes.

Edit again, the effect only effects the wind speeds apparently so im chatting ****.

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#### piggeh

Associate
The plane will land at the South Pole if it is always heading South. Or crash at the south pole if it keeps heading south without landing at any point.

Soldato

#### Jokester

Don
I was thinking the same thing, by maintaining a heading it takes the whole issue of the earths rotation out of the question as you would be compensating for it.

#### Mason-

Soldato
If it's always flying directly south then you'd assume even if the spin of the earth was faster than the plane; the plane is adjusting to flying south the whole time. Obviously until it loops over the south pole and is flying north.

#### sbi5ar

Soldato
You'd never go back to London if you only flew directly south!

True story...

EDIT: just read through it properly and as said above if you headed south on a heading to go right around you would land back on the runway due to the meaning of heading etc...

#### Scuzi

Man of Honour
The aircraft will have to change heading to follow that route, even in still air. (Unless you are using a couple of very big polar stereographic charts with Grid North aligned with the Greenwich Meridian and you fly a constant Grid heading, but that's splitting hairs )

The aircraft will travel relative to the air mass in which it is flying. Earth's atmosphere moves roughly with the rotation of Earth (assuming no weather phenomena), therefore you can assume that discounting a wind vector, the aircraft will rotate with the earth.