Quote:

Original post by TFBC_Jason I would go with the real reason the Earth will no longer be around... in 2012, the magnetic poles will reverse, completely flipping, which will cause the entire planet to flip back to its comfort zone. It will do so, so violently, that anyone not nailed down will be flung into space. Anyone left will be surely crushed by the force of their own inertia when the Earth suddenly stops after its half rotation.

That's really not at all how that works :(
It takes tens of thousands of years for the poles to complete a reversal, which does not affect the physical spin of the planet... Plus precursors of human-kind have survived such an event in the past.
I can only hope you're taking the piss out of 2012 doomsday 'theorists' ;)

May as well have Nibiru collide with Earth while it's undergoing this 'instant flip' and have all the tectonic plates flip upside down too ;P

[Edited by - Hodgman on February 15, 2010 1:35:51 AM]

An unpenetrable field around the Earth. What's going on on Earth - no one knows. Reason for the field - unknown, maybe aliens or experiment gone bad.

A mostly natural approach: Yellowstone -> cascade of earthquakes and volcanic activity -> release of enough toxic/radioactive substances (possibly including nuclear waste, atom bomb caches, etc.) -> ecological collapse and sudden ice age -> rather long-term terraforming effort.

A mostly man-made approach: some "harmless" new chemical substance (presumably very useful and widespread nanoparticles) reacts unexpectedly with something common, producing an almost indestructible compound that accumulates into cells and interferes with meiosis.
Before the above is discovered, almost all life on Earth cannot reproduce any more. What new life will spring from this age of exceptional natural selection? Sequels will tell.
Spacefarers keep the contamination on the planet with deadly force.
Earth might become a one-way trip destination that old people want to see before they die (and maybe where discriminated people are deported); if sufficient decontamination technology exists there could be some trade.

- Genetic engineering goes haywire, plants take over the world
- Sun becomes unstable, people flee the solar system
- Unpredicted nuclear chemical reactions create a layer above the earth's atmosphere making the planet inhabitable

Why don't you make the Sun turn into a Red Giant. This distroying everything in its path. At this time even if you have your story 5 billion years in the future as it were And even by chance there is life still left on Earth Have chaos strike through out Earth? Then have some military Government get on their space craft and Planet hop through the rest of our planets to survive. Who knows what you will find at the end of the Solar system.


New creatures or humanoid beasts?

A slow build up of volcanic gas gradually formed into a giant pressure cavern under the mid-Atlantic ridge. Eventually the crust, thinned due to magma not being able to replenish the ridge as the American and Eurasian plates drift apart, began to tear. Super heated, poisonous gasses were released into the atmosphere, as the clouds drifted east on the trade winds around 100 million people were lost in Western Europe in just a few days, but the worst was yet to come.

Shortly after the first clouds of gas descended, and as the pressure under the ridge decreased, the cavern, now unable to support the massive weight atop it, collapsed, taking a 1000 square mile section of crust with it. This massive displacement caused world wide earth quakes and tsunami's, instantly spreading destruction on a global scale, fracturing and cleaving the Earth's crust like it was egg shell.

And as quickly as the sea rushed in to these open cists of fire, super heated steam, rock, and ash exploded out miles into space, scorching the atmosphere, tearing it away leaving the Earth barren and lifeless.

Alex

Maybe they wanted to get out of our solar system and were experimenting with more efficient power generation (antimatter), but somebody screwed up and the planet evaporated in a matter-antimatter annihilation?

Quote:

Original post by Katie The Civil War of Humanity began when the colonies on Earth's moon and Mars declared independence.

That reminded me of part of the back-story to Zone of the Enders. A Martian revolutionary group tried to sabotage Earth's space elevator by destroying the counter-weight, so that it whipped around the planet and caused massive devastation. In that story, the plot was prevented, but its semi-plausible.

If you wanted to make Earth uninhabitable, something similar could be done. Perhaps coordinated colony drops a la Gundam.

I'm actually partial to the idea of the technology used for enabling space travel also inadvertently destroying the Earth, as was suggested earlier.

Quote:

Original post by Rycross If you wanted to make Earth uninhabitable, something similar could be done. Perhaps coordinated colony drops a la Gundam. I'm actually partial to the idea of the technology used for enabling space travel also inadvertently destroying the Earth, as was suggested earlier.

The idea is a lot older than that - Heinlen had his revolutionary moon colonists dropping containers of rocks on Earth with a simple mass catapult (which is also the bulk transportation method).

I'd choose F, for novelty value. You'd leave people wondering where the Earth went and you could go for the comic book death and bring it back.