[Kie99]

Heat death of the universe.

[Maniax]

Snopes.com isn't too sure it was Einstein that said that quote:

...All in all, this looks like a classic case of a useful quote's being invented and put into the mouth of a famous person for political purposes.

Though that doesn't necessarily mean the danger isn't true.

[Uchuujinsan]

It wouldnt mean the danger is true if Einstein said it, on the other hand ^^
A simple fact, not all plants need bees or even other insects to reproduce, so the importance of bees is exaggerated

[TrashMan]

A super-mutating  super-virus that turns people into mindless zombies /raving mutants /corpses.

[Mars]

Thanks to everyone, there have been a lot of good ideas posted. I would never have come up with the moon decaying in orbit for instance.

[ShadowGorrath]

Ever saw the movie "Time Machine" ? At a part of the movie, it has humans make colonies on the Moon. And sometime in 2017-2027 they detonate a bomb under the Moon's surface, to make space for colonists. However, the detonation goes wrong, and not only screws up the  Moon's orbit, but also craks it, so it starts to fall apart, while screwing up everything on Earth. In around 2030, Earth is like after an apocalypse, with people trying to evacuate.

[Retsof]

Gas giants' moon systems are stable, yes?  Well, for story purposes, you could have a moon slingshoted close to the Earth, disrupting the Earth/Moon system and messing with techtonics.  Perhaps it ends up on a highly eliptical orbit, not doing much on one pass but the effects building up over time.

Oooh! make it Europa or one of the other water worlds, this could give you the new life aspect as the ice will melt when it gets closer to the sun, or atleast giving an interesting place to colonize.

[BengalTiger]

OR you could use an object the size of Pluto on a 90% chance collision course with Earth (with impact in 20, 50 or whatever years). The object would be too big to nuke or push within the time limit, and have a too large hit probability to ignore.

Obviosly half the time from learning about the threat to the evac of Earth, people would argue about who gets saved, and who doesn't (and possibly start a war or two about it, limiting the grand total of seats to a few thousand due to damage taken by the global industry and science facilities).

And finally, the miniplanet could miss.

All the 'doomed' people who were left behind, to celebrate the day the Earth survived against the odds, shoot down all the escaping ships (which were still in range Earth based weapons, despite almost reaching the Moon) and enjoy the fireworks.

[General Battuta]

But I thought he was trying to actually force people to go to Mars. (As amusing as that scenario is.)

[Flipside]

What would be funnier is if the planetoid missed and proceeded to plough through the Armada of escapees

[Snail]

What would be funnier is if the planetoid missed and proceeded to plough through the Armada of escapees

lol

[TrashMan]

All the 'doomed' people who were left behind, to celebrate the day the Earth survived against the odds, shoot down all the escaping ships (which were still in range Earth based weapons, despite almost reaching the Moon) and enjoy the fireworks.

Which would be wicked and sick.

Usually in scenarios shuch as this, one would pick young, healthy and intelligent people to further propagate the race.

What would be beneficial if all the retards and stupid people got fried...and whatever ship(s) carried the government gets fried too.

[BengalTiger]

Well to add a twist to the already twisted ending-

The mini-planet flew by the Earth, just barely touching the atmosphere. Moments later, the left behinders watch as the lasers start illuminating the sky, and the nukes fly off.

They begin reaching their targets, producing mighty fireballs, visible to the naked eye. The population starts to celebrate the 180-degree turn in the fate of humanity, most are in shock that they're not dead, others are in euphoria that they were the first potential evac candidates not to make it to the spaceships and some still don't really understand what's happening.

In the mean time, the person who pressed the red button, a general who had to stay because he didn't have the political connections in the Selecting Comittee needed to get a seat in the life boats, yells out:
"Chosen people my @$$! Eat this, (0(k-suckers!"

Edit: When I'm done with TotT, I might just create a campaign based on this.

[TrashMan]

Add another twist...the asteroid misses and the people left on earth fire ze missiles at the fleeing ships. then

a) the missiles malfunction and explode, turning Earth into a nuclear wasteland
b) another planetoid comes and f*** Earth up
c) something else

[BloodEagle]

Add another twist...the asteroid misses and the people left on earth fire ze missiles at the fleeing ships. then

a) the missiles malfunction and explode, turning Earth into a nuclear wasteland
b) another planetoid comes and f*** Earth up
c) something else

d) underpants
e) ....
f) profit!

[BengalTiger]

g) the escapers disarm the nukes before takeoff, and the fireworks are a decoy
h) the escapers plant their own nukes on Earth, in case the asteroid misses
i) Nuke can finish for me.
j) this doesn't make sense anymore

[ShadowGorrath]

v) I don't know the alphabet

Seriously- stop it.

[Odd Writings]

And now for something completely different.

A scotsman on a zero-G based, five legged, armor-carapaced hors--wait, wrong script.

What about the explosion of a supervolcano like, say, yellowstone park? It'd take out mankind no problem within a year or so if the initial blast won't off us all.

Or what about a nearby star going kablooie and giving us about 7 years before the shockwave hits?

...hm. doubt that Mars would survive that either.

There IS one thing you could use instead of disaster, though. what if the Mars rovers etc. found alien tech on Mars? Like hell that the world would not want to be there post haste.

[Mars]

Oh boy, dangerous alien tech. That's sounds like exactly the thing I want in my backyard. 

[General Battuta]

Or what about a nearby star going kablooie and giving us about 7 years before the shockwave hits?

...hm. doubt that Mars would survive that either.

There IS one thing you could use instead of disaster, though. what if the Mars rovers etc. found alien tech on Mars? Like hell that the world would not want to be there post haste.

And how would you know it had exploded seven years in advance? It's gonna take light seven years to reach us, and the neutrinos will be right behind that.