Everyone loves to see the moon at night. It’s the only celestial body that is clearly visible to our naked eyes. What if one day you are checking out moon romantically and you see it moving towards you? What if somehow the moon falls on the Earth? How would it affect the Earth?
Or would the Moon even reach the Earth’s surface? Or would it just get torn up due to Earth’s gravity?
Let us first clear up a few facts about Moon, our only satellite. Moon was formed about 4.6 billion years ago, that’s 30-50 million years after the formation of our solar system. It’s around 3475 km in diameter and mass of 7.35 x 10^22kg (i.e. 0.01 of Earth’s mass). It is a quarter of the size of planet Earth. Its temperature of surface varies from -173 to +127 degrees celsius. Its atmosphere is very thin. It causes the ocean’s tides. It is on average 384,400 kilometers away from the Earth. It orbits the Earth every 29 days.
So, what would happen if the Moon crashed into Earth?
Moon’s gravitational pull causes tides on Earth. It also keeps Earth stable on its axis, making our climate liveable. So yes, Moon makes Earth a more habitable place. Let’s say the Moon starts its journey towards the Earth’s direction. But Moon will never make it to the Earth’s surface as Moon’s plan to collide with Earth will break Moon into pieces once it reaches Roche limit.
Whats this Roche limit? It is the point at which the gravity holding a satellite together is weaker than the tidal forces trying to pull it apart. So the Moon can only get close to 18,470 km from our planet before it gets destroyed into pieces. All the craters from the moon would scatter and form a ring of debris above the Earth’s equator with 37000 km diameter.
This would make Earth the second planet (after Saturn) in our solar system to have a beautiful ring. But our ring would not last long. The debris of the moon would fall on earth eventually, smaller ones first and then the bigger ones.
It would look like thousands of asteroids attacking the Earth. It would look beautiful, but it would wipe out entire cities in the process. But this is not when we will die, Moon will start affecting it as soon as it begins its journey towards earth.
This movement of the Moon will increase the impact of tides on the ground as well as oceans. By the time the moon has hit the Roche limit, it would cause tides as high as 7 km. Coastal cities would get destroyed by frequent tsunamis. Ocean life would have a very tough time. Earth’s rotation would also speed up making our days shorter and shorter.
The overall temperature would go down. The climate on land would get affected. No one would worry about climate change anymore. Let’s hope that Earth is not burned due to asteroids. In this case, there would be no one alive to worry about it anyway.