We've talked a lot about “where the moon may have come from?” But what if there was no moon at all? What if you woke up tomorrow and that giant rock four hundred thousand kilometers (400,000 km.) away was just—gone?
The truth is there probably some pretty major consequences. However, the worst of them wouldn't show up overnight.
When you think about the moon's effects on Earth. You probably think tides first. Why not? Tides are produced by the gravitational attraction of the moon and the Sun—but mostly the by moon. The moon is always exerting its gravitational pull on Earth and our planet can hold onto everything on it, except its water. So, we get about two high tides and two low tides every day because of these—Sun and Moon.
Without the moon the bulge of the Earth's water would still follow the Sun but because it's so far away—tides only be about 40 percent as large. Then, the high tide would happen around noon each day.
Just imagine the night sky without the moon. Sky watching would be awesome than ever because there'd never be any moonlight to interfere. However, it would also be dark every night too.
The full moon is only 1 over 400,000 (1/400,000) as bright as the Sun but that's enough to make a big difference to us and other animals. Moonlight obviously helps nocturnal predators which have evolved to hunt in low light. On contrary, it also helps the prey to detect the animals that are trying to catch them. So, without the moon the food web would be really different—really fast!
The moon is responsible for more than just tide and nightlife. Its most important job may actually be stabilizing Earth’s axial tilt. Earth’s axial tilt relative to the Sun varies between 22.1 to 24.5 degrees and its tilt that gives Earth seasons.
However, much like a spinning top, Earth and other planets are susceptible to wobbling as they spin on that axis. Luckily, we have our moon to stabilize any potential fluctuations. Its gravitation helps counteract disturbances caused by nearby planets like Venus, especially, Jupiter that would otherwise cause earth to wobble more than we'd like.
Planets without large moons aren't so lucky. Take Planet Mars which currently has about 24 degree axial tilt. Because Mars only has two small moons and due to the gravitational forces of its neighbors scientists believe that its tilt is fluctuating between 15 to 35 degrees over time. At one point, causing its Polar ice to drift all the way to the equator. But thanks to the moon! Our axial tilt stayed consistent for hundreds of millions of years.
Without it, we’ll be subject to fluctuations even worse than what Mars as seem. Sometimes, our tilt would be zero with Earth standing straight up and down which would cause an end to the seasons. In the other times, the tilt could be eighty-five degrees. We basically rotating on our side like Uranus does.
In which case, each hemisphere would experience night time for half a year. Plunging the planet into darkness and cold while the other six months of the year would be constant daylight and temperatures that would put the tropics to shame.
In addition to stabilizing our tilt, the tidal friction caused by the moon also acts as a very slow break on the Earth's rotation. Not a huge impact our rotation slows about one second every sixty seven thousand years (67,000 yrs.) However, take the moon away and things could speed up in a hurry. That’s because over a billion years ago before moon existed. Many scientists believe the Earth rotated three to four times faster than it does now. This means that back then, a day on our planet was only eight or nine hours long. The formation of the moon slowly applied a gravitational break as it continues to do today.