BaldRick wrote:
So .. Earth is rotating at 1k MPH ( I understand the 1 rotation per day equals 1k MPH at the surface ) and it suddenly stopped turning , anyone stood on the Equator would continue moving forwards at that speed . Ouch .
If Earth ceased rotating the ISS would continue travelling round in orbit at a speed of 17k MPH (ish) ?
The same speed would be require to stay in orbit, but a boost would be required to compensate for the gravitational drag caused by the stopping of rotation.
BaldRick wrote:
Oooh ! That brings more questions . If Earth is rotating at such a high speed (at the equator )how do aeroplanes manage to move in both directions around it ?
Irrelevant. Planes only have a velocity in forward flight RELATIVE TO THE EARTH. Thus wherever they take off from, they only CHANGE their speed relative to the surface.
BaldRick wrote:
It would make sense that you only have to get yourself clear of the ground and stay static to have Earth move underneath you . You could be a thousand miles away from your start point in an hour . But it doesn't work like that does it . That would mean that a plane travelling in the opposite direction at over a thousand miles an hour to make any progress at all . I assume that it is possible for this scenario to happen , but at what altitude .
You can't "stay static". You have to travel faster than the Earth's rotation (how much faster depending how high you are) to appear to hover over the same spot.
In space a geostationary orbit is possible in what is called the Clarke belt (after Arthur C. Clarke) and is 35,786 km high.
BaldRick wrote:
Does the ISS travel in the opposite direction to Earth's rotation to enable such high speeds ? And how is it powered to keep it at that velocity ?
No, all spacecraft take off in the direction of the Earth's rotation, precisely to take advantage of the boost in speed this offers, and for the same reason, space bases are as near the equator as practicable, as there the Earth is spinning the fastest.
Once the boosters have boosted it into orbit, the ISS has a certain amount of fuel which it uses to regularly raise its orbit, to compensate for the deceleration caused by atmospheric drag.
