Quote: FLAT STANLEY "[iA serious Question to the OP.
Now i've pre-booked a non stop flight from[/i rlSKYSANNERrl
London - Warsaw. Flight time 3 hours 50 minutes. ( Travelling East with the Easterly Wind )
Warsaw - London, Flight time 4 hours 20 minutes ( Travelling Westward Against the Easterly Wind ) Hence a 30 minute difference.
[iSo if we live on a spinning Ball travelling Eastward at 1000 mph how are these flight times with the exception of wind speed possible they're the same flight time with the exception of the tailing wind. Surely with the Earth's supposed spin these times should differ.?. I'm well aware of the Relativity Theory but it doesn't add up. If the Earth is spinning Eastward at 1000 mph and the plane is moving 500 mph in the same direction what is going on here thanks.
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1. The wind speed and direction is extremely variable, but in general, as any image from space will tell you (or any weather map) air currents are in broad terms curved, or circular (picture a huge hurricane system).
2. Wind speeds aren't (hurricanes and cyclones apart) that great but as planes fly in air, their airspeed always differs from their groundspeed, as the air is never stationary.
3. The atmosphere is part of the globe, it isn't separate or detached. If, for example, you watch a speeded up video of a hurricane system you will see that it will track along a curve towards a general direction, and this motion will continue, irrespective of the spinning of the globe. The principal effect of the spinning of the globe is, of course, the well-known Coriolis effect. (The anticlockwise rotation of the Earth deflects winds to the right in the northern hemisphere and to the left in the southern hemisphere. If the globe did not spin, this would not happen).
But the hurricane as you watch it will go round and round with the globe, as well as its motion relative to the Earth's surface. You can witness the same thing on other planets, e.g. Jupiter's famous red spot. Although Jupiter is a gas giant, so the comparison isn't exact, but still you can see that the weather systems spin around Jupiter, irrespective of their local currents and movements, as the planet as a whole rotates.
4. So, the atmosphere as a whole goes round and round just like the ground beneath it does. And indeed as the liquid oceans do, though they too generate worldwide currents.
5. A plane taking off in any direction is already "travelling" at the same speed and in the same direction as the piece of ground on which it is situated. Apart from the local wind conditions, which at ground level may be anything from a few mph to 20 mph on most days, the plane leaving the ground only needs to reach it's take-off airspeed, relative to that wind. (So if it is taking off into a headwind of 30 mph, and if it become airborne at 100mph, this will occur at a ground speed of 70 mph in this situation, as 70mph plus 30 mph gives the air a speed of 100 mph over the wing surfaces and lifts the plane off the ground.
6. Once in the air the plane can fly in any direction it wants, and its air speed will depend on how much power the engines are set to generate. Its ground speed will be the product of its airspeed plus or minus the net wind speed at any given time in the direction of travel. In (for example) a favourable and strong Jet Stream, the plane can get from A to b significantly faster, using significantly less fuel. Into a headwind, the plane will conversely need to apply extra power to increase airspeed, if it wants to maintain the desired groundspeed and land at the desired time.
7. The Earth's spin is not really anything to do with it, because as I have explained, the atmosphere overall (local currents notwithstanding) as a whole, spins at the same rate as the Earth spins. If you want to look at it another way, if a plane is on a runway which is "spinning eastward at 1000 mph" and wants to fly east, it will need to achieve its takeoff speed in an easterly direction. If that is 150 mph then as the plane leaves the runway, you could say it is travelling eastwards at 1,150 mph, if you take into account the Earth's spin, but of course you don't, any more than it would be useful to claim the plane was travelling eastward at 1000 mph as it stood on the tarmac. It isn't. Relative to the globe, and therefore relative to our arbitrary compass points, the stationary plane isn't travelling in any direction, for the purposes of us humans on the surface of the planet, or indeed its passengers. They can sit on the stationary plane for 24 hours, and will by then have "travelled" one spin of the globe, at 1000 mph or whatever, if you want to measure their journey through space in that vector, but unfortunately for them, that will position them in precisely the same spot as they started off from, because the ground they are on has done precisely the same journey.
From the plane's perspective, it hasn't moved at all. At least, not relative to the planet it sits on. If however the pilot wanted to know how far his plane had moved through space, then that would be quite a different matter. For just one example, we're in the Milky Way galaxy and that galaxy is moving at 1.3 million mph (2.1 million kmh), in the direction of the constellations Leo and Virgo. And so therefore, give or take the necessary local adjustments for local factors such as our speed of rotation around the Sun, and the speed of rotation of the solar system around the Milky Way, am I, and so are you.
1.3 million mph is quite a rate of progress in one sense, but not much compared to the speed of light, which is in round figures 670 million mph.