What would happen if the Earth and everything/ everyone on it suddenly stopped moving, but the atmosphere retained its velocity?

Firstly (and quite bluntly), everyone dies…

Earth rotates at a speed approximately equal to $460 \ ms^{-1}$  (>1000 mph) at the equator. So if Earth and everything fixed to it were to stop moving but the atmosphere continued to move, effectively we would have winds relative to our motion of approximately $460 \ ms{-1}$! The most devastating winds that have affected Earth in recent times have had speed of up to $120 \ ms{-1}$, so in other words… we would have a bit of a problem!

Wind would be fastest at the equator and slowest at the poles (because the equator moves through a distance of 40 million metres 1 day whereas at the very ‘tip’ of each pole, they don’t really move through any distance in this time (they simply rotate).

What this means is that everything living between 42 degree north and 42 degrees south would experience supersonic winds (this would not be good for over 85% of the population of Earth).

These winds would results in massive amounts of friction with Earths surface (which would result in the winds eventually slowing down), but before it being slowed down enough almost all of humanity and its structures would be wiped out and likely annihilated!  So who would survive?

• Most people and animals above ground would die, but those underground would have a chance of survival, including those in subway tunnels!
• Scientists and staff at the
station at the south pole would be okay. The first sign of trouble for them would be when the outside world suddenly goes quite!
• The mysterious silence would probably distract them for a while, but eventually someone would notice something even stranger… “The sun isn’t moving, earth must have stopped spinning destroying everything in a global tempest!”

What would happen to they air?

The good news is that eventually the air would slow down… so providing some of humanity survives, we could rebuild and start again. But in the meantime, things would get weird as the winds slowed down…

1. The air would be moving ridiculously quickly and would therefore have lots of kinetic energy, as the wind slowed down, this energy would be lost due to friction (and due to conservation of energy) and would therefore transfer into thermal energy and the wind blast would translate into a heat blast! Winds over land masses would heat up to scorching temperatures and iIn areas where the temperatures are moist, you would get global thunderstorms.
2. The wind sweeping over the oceans would churn up and atomise the surface layer of the water; for a while the ocean would cease to have a surface at all and It would be impossible to tell where the spray ended and the sea began!
3. The sea is pretty uniform in temperature, at about 4 degrees celsius, varying only slightly (in the great scheme of things) around the planet.
The spray on the surface layer of the ocean would cause atmospheres that spread across most of the globe like none that have ever been seen before. This merge of cold water moisture with superheated air, would create the type of weather that would be a mix of wind, fog and rapid temperature changes.
4. This would lead to blooms of life, as fresh nutrients flooded the upper layers. At the same time it would lead to huge die-offs of fish, crabs and animals ion whom would be incapable of coping with the influx of low-oxygen water from the depths. Animals that need to breath, such as whales and dolphins would struggle to survive in the turbulent sea-air interface.
5. The waves would keep sweeping East to West (because of the direction Earth was spinning prior to it stopping) and every East facing shore line would encounter the largest storm surge in our history. A blinding cloud of sea would sweep inland and behind it a wall of water would advance like a tsunami.

Day & Night

The windstorms previously mentioned would throw huge amounts of dust and debris into the atmosphere and a dense blanket of fog would form over the oceans in particularly. Normally, this would cause the global temperature to plummet (because the suns heat would not be able to penetrate this fog), and plummet they would, on one side of Earth at least anyway!

If Earth stopped spinning the normal cycle of night and day would cease. The sun wouldn’t completely stop moving across the sky, but instead of rising and setting in one day, it would rise and set in one year. Day and night would be six months long each, even at the equator. The daylight side would scorch under the sun, this would lead to convection currents which in turn would lead to additional massive storms in the area being directly heated beneath the sun.

It doesn’t stop here! The moon would continue to go around Earth…

Although the length of one day would change, the length of a month would not. After all, the moon would not have stopped rotating around Earth. However without the Earth’s rotation feeding it tidal energy, the moon would stop drifting away from us (as it is currently doing – but only by about 4 cm per year!) and would start to slowly drift back towards us.
In fact the moon (like a faithful companion) would act to undo the damage caused…

Currently the Earth spins faster than the moon, and our tides slow down the Earths rotation while pushing the moon away from us. If we stopped rotating, the moon would stop drifting away from us. Instead of slowing us down, its tides would accelerate our spin, quietly and gently the moons gravity would tug on our planet… and earth would start spinning again!

In the meantime, there would not be a cycle of two rise and falls in tides per day, there would be two rise and falls in tide per month!