Destruction Earth

It is quite often said that their is a commet or meteorite of some sort heading for us [the earth] in 2066 or something there abouts and that it may or may not be big enough to wipe out the planet or rather the various things that live on it [humans for example] it is allso often said that various geverments are doing nothing to combat this the resons for this what could they be?

1. The world is run by death cultists who want the world to die.
2. There is nothing that can be done about it.
3. Those in power wish to use this opportunity to wipe out most of the population and start again. [while they of course are on the moon]
4. They know that in fact there is nothing heading for us and they just made it up to distract us.

I can think of no other possibilitys, perhaps you can?

Flaws in these ideas may or may not be.

1. weather they want us dead, know they can't do anything, or are death cultists, why don't they simply give the impression of doing something?

Either this that or the orther and we're screwed either we're dead or being massively manipulated and most probably both.