Earth's rotational speed is slowing down, what happens if it completely stops???

What happens if Earth stops spinning???

Even if we had a bad day we rest easy and say that tomorrow would be a new one, but that might not be the case forever. The Earth's rotational speed is slowing down by the second due to various factors. And once it stops the lack of a 24 hour day would be least of our problems.

But first, let's discuss the rotation of a planet, usually planets which don't experience any external force other than their stars gravitational pull doesn't spin. Well Earth is a special case while the earth was being formed a Mars-sized object crashed into our planet and provided Earth with it's spinning momentum and the material which escaped into space due to the impact made our Moon which then settled with Earth in a balanced gravitational relationship and now causes tides on Earth, but it was not always so pleasant and smooth in fact the initial speed of rotation of our planet was so fast that a day was just 6 hours long. This is where the tides come into play, with every tide cycle it creates friction on the surface of Earth and results in slowing down its rotational speed ever so slightly. With decreasing speed the Moon increases its distance from Earth. The tidal waves do cause Earth's rotation to slow down but the laws of physics won't let it stop completely. 

But with a bit of science, we can figure what it would be like to live on a non-rotating Earth. First, the Earth would have half a year of daylight and half a year of night similar to tidally locked planets like Mercury. This makes days much hotter and nights colder, especially at the polls due to Earth's tilted axis, this would result in a change in global wind patterns to North-South orientation moving from cool equators to hot polls the mid-latitudes would be the few habitable zones with right atmospheric densities on the whole planet if there is land to live on. 

Due to Earth's rotation, it has bulged at the equator and once Earth stops spinning there would be no bulge and the oceans would migrate towards the polls leaving a mega-continent around the equator and that new continent would have an interesting geology as the layers would Earth would slow at different rate causing massive Earthquakes and volcanic eruptions until Earth completely stops. Once the Earth stops things would get way more dangerous for any life form as with Earth its iron core would stop too which causes the magnetic field around the Earth without it Earth would be vulnerable towards the Sun's radiation.

If that doesn't kill us then the lack of 24 hour day might, recent studies have shown that the Circadian clock that controls all living things is actually at the cellular level even species which do not rely on sunlight like muscles show more gene expression based on Circadian cycles than the rising and falling tides that drives their muscular activity. And of course, the plants and planktons which are present at the bottom of the food chain need sunlight to stay alive and they surely can't withstand 6-month long night.

The good news is that our planets slowdown is super gradual, in last 100 years Earth's rotation slowed down by 1.4 milliseconds, it would take 180 million years to make our day 1 hour longer. That's a long time to adapt, well who knows we might even be a Stellar Civilization.