Is the falling object from the sky a threat that may soon become real? What is being done to possibly counteract this threat?
Do we need to worry about this threat happening within our lifetimes?

The Air Force has a project running that's cataloging all the NEO (Near Earth Objects) and their orbits. Maybe in the near future we'll know with a higher degree of certainty if there is anything out there with our name on it.

what can we do even if we do spot one (nothing) and even if we could no one would spend the money why would a goverment spend money on that when it can spend it on them selves promoting what they have achieved, unless we can break away from earth soon then there will not be any thing to save.
the rock hits in 2048 i believe and what have we heard in the papers nothing because it is to big to do any thing about ..

Rob, You say there is a rock that is going to hit us in 2048 and we know about it?

i guess you dont like i said not many have but there is one and it is the type we call a planet killer just ask around it is there and getting closer but hey not my problem i will be long gone by then so why should i worry about it ..

I wouldn't worry too much about the asteroid that some are saying will hit in 2048. There is no guarantee of this. In fact, many things can happen between now and then to change it's course. At this stage, it's have to be really close for us to be certain of where it'd be.

As for the whole situation, the problem is that it's not the hotest subject right now, so not many scientists are working on the problem. Also, it's very difficult to get the amount of telescope time needed to observe NEO. If anyone on this board is an amateur astronomer and wants to get involved, you probably can make an impact. It's happened with comets and can happen here, too.

I thought they said that 2048 asteroid wouldn't hit the earth.

It's that fractal/chaos thing about the beat of a butterfly's wing 2000 years ago would or would not have given rise to the Third Reich, etc. etc.

Meaning, in the present context: since the measurement of position and velocity of these objects has an associated error of measurement - no matter how small, but a finite amount nonetheless - then there is always some uncertainty about predicting future position from present-day data.

This is especially true in the case where the body interacts gravitationally with others - and in this case, that's the moon and the earth, primarily, I believe. Now, at the extremes of measurement error, it turns out that path X will be chosen, with a very small probability (because it lies at the extremum of the error). And then, in a similar fashion, after another interaction, path Y, and so on...all at the extrema of error.

One of these highly unlikely combinations results in this thing being partially captured by earth...slowed down to such an extent that it boomerangs...and finally comes BACK and wallops us!

But, as I've described, this scenario lies way off to the side of the set of most likely sequences of events - which result in nothing untoward whatsoever happening.