What happens.....when earth...?

Irratic weather patterns would be one of the consequences...

Weather patterns that are greatly different from the one's we are familiar with...

Just look at that moon. Isn’t it lovely? But beware: the moon isn’t just there to entertain us. Without the moon, we could be doomed.

There’s always the small but alarming possibility that some dreadful cataclysm takes out the moon. Some billions of years ago, this almost happened. On one terrible day, a vast comet struck the moon, carving out what’s now known as the biggest impact crater of the entire solar system: the Aitken Basin, a huge, 2,500 kilometers wide scar on the moon’s South Pole.

Ok, but what’s the big deal?, you ask.

Well, not too many people know this, but the moon is what keeps our planet stable. Without it, we would find ourselves on a hostile rollercoaster world. Our planet would go berserk.

For one thing, the moon tugs at the oceans. This gives us the tides. No moon, and the floods would immediately be about 2,5 times lower -- some minor tidal motion would remain, because the Sun pulls at the oceans, too.

The consequences would be dramatic. Many fertile deltas would dry up. Other areas would become permanently inundated. There would be all kinds of changes to nature. All over the world, people would face droughts, famines, diseases and wars.

And to cheer you up a little more: that’s not the worst part.

The moon and the Earth are locked into a twin system, much like an athlete about to hurl a hammer.

Crucially, the moon also stabilizes the axis around which the Earth rotates. You could compare the Earth-moon system to an athlete swinging a hammer around. Take a good look at the picture on the right. Now, ask yourself: what would happen if the rope suddenly snapped? You get the idea: the athlete would fall over.

Exactly the same thing would happen to the Earth if you took away the moon. Right now, our planet rotates at an axis that is tilted about 23 degrees. It has always roughly been that way. But without the moon, the Earth’s rotational axis would slowly drift off, because of the pull of the other planets -- especially Venus and Jupiter. So one moment you’re in Africa; the next, you’re on the North Pole!

In the long run, this would cause massive, unpredictable and abrupt climate shifts. The Earth would heat up, freeze up, and heat up again. One moment, your nose freezes off in a massive Ice Age. The next moment, you find yourself sweating your eyeballs out, in a period of soaring heat.

Even worse, our planet could tip over and ‘lie on its back’ for some millions of years (or longer). One half of the globe would be in constant sunlight, while the other half would be plunged into everlasting darkness -- and in cold.

We’d have a two-sided planet. And to be honest, you probably don’t want to live on either side. The southern half would become a barren, waterless, roasted desert world. The northern half would be an equally barren, dry, ultra cold ice world.

Ok, so you decide to live in between the sunny and the icy side. There, you might find a small zone with good old days and nights, and mild temperatures. But there’s a downside: the region will be harassed by HUGE, everlasting storms. With temperature differences like that, there would be massive flows of air between north and south.

And actually, that’s not even the biggest concern. For chances are the massive, abrupt climate shifts will at some point kill our world altogether. With the moon gone, our world could become a lifeless, dead planet in the end. The sweeping climate shifts could at some point disrupt the Earth’s atmosphere for good. This is probably what happened to Mars (once watery and friendly, but now as dead as a doornail). Mars indeed tilts like a drunken athlete: it tips over to about 60 degrees!

And that’s not everything. When the moon gets smashed up or knocked off course by a super big asteroid, it’ll probably rain debris on Earth for many years. For years, we’d have to wear hard hats - only to find that hard hats don’t help against big, incoming chunks of moon rock falling down on our world.

Still, there’s some good news, too.

According to some doom prophets, without the moon, our planet would start spinning wildly, like a whipped top. A day and night on Earth would last only an estimated four to eight hours. And we would have HUGE, apocalyptic storms, tens to even hundreds of times stronger than anything ever seen on Earth, and each one of them lasting many years. Cities and forests would be flattened, agriculture would become impossible.

But fortunately, the doom prophets saying this have got it all wrong.

The moon has slowed down the rotation of our planet for good. The moon puts the brakes on our planet, because the tides serve like a sort of ‘counter weight’. Over the billions of years, this has slowed down the rotation speed of the Earth. But if some rogue black hole suddenly snatched away the moon, our

Well, it's not going to happen. The current IAU definition of a planet is that it is an orbiting body that has already cleared its orbit of other sizable bodies. In other words, there is nothing in the orbit of a planet for it to collide with, that could 'knock it out of orbit'. (The extinction level meteor collisions popular in disaster movies are of course possible, and it would be bad news for us as a civilisation, but would not harm the Earth as a planet)

In the early history of the solar system, such collisions did happen, and we are still studying the effects.

Then happens Boo!!! Well, there's plenty of examples about planets colliding with something other stuff like planet or else. If earth goes outta it's orbit life on earth will end immediately coz all the forces balancing and working in our universe will get disturbed. It might also affect our solar system negatively. And collision of planet with other one is quite depressing and would be totally devastating. It'd cause release of enormous unwanted energy.

I'll be concise. What happens when you're driving a car on the turnpike and another car came at you, let's say sideways? It'll knock you you off the road. The same thing would happen to earth if ever a body its size or even smaller, like the moon Edward has brilliantly talked about here (good job, Edward) should hit earth violently. I guess there wasn't much to guess. The answer spoke for itself.

What happens when 2 planets collide? Cocoa Pebbles go everywhere!

Earth getting knocked out of orbit? Not likely, don't worry about it.

Doom, we would all die. The chances of your house being hit by a bus as you sleep in your bed is probably 100 billion times higher than the chance of a rogue planet appearing in our solar system

The chances of you catching a cold is 1 billion times higher than the chance of a bus hitting your house while you sleep

The chance of you dying from any cause is 100%, We will all die one day, hopefully this won't happen for you until you are over 100 years old

At this point in our Solar System's history, these are events that can _never_ happen. There are no large objects floating around which pose a danger to Earth, and the chances of a new one appearing are billions to one.

Everyone dies.

But nothing like this has happened in the past 4 billion years, so don't worry about it.