We didn't find the arsetoid in 2029. We found the arsetoid YEARS ago, and because we can do advanced math, we have a pretty good (but not exact) idea of where it's going to be in 2029.Things whiz past us all the time that we only see when they happen, or even sometimes after they happen, because we didn't know they were coming, and they were so small that they were hard to pick up if you weren't looking for them.(Most arsetoids are discovered by chance a telescope happens to be looking in the right place at the right time, and sees one that's never been seen before.)Once we've observed an arsetoid a few times, we can predict its orbit and figure out where it's going to be with a fair amount of accuracy.Now, planets are different, because they're HUGE, and reflect a lot of light. They're easy to see, and they'd bet VERY easy to see a new one coming out of nowhere, even decades away.Therefore, the only reasons we might not see something today that is supposedly going to be here in 2012 are:1. It's very small.or2. It doesn't exist.It's simply not possible that we would miss a planet-sized object cruising through the outer solar system, on the way to earth. Everyone on the planet would be able to see it.Heck, you can see Jupiter's 4 big moons with a decent pair of binoculars, and one of them is smaller than our Moon. (And Jupiter is a lot farther away than 3 years, even if it suddenly stopped going around the sun and headed straight for us.)The only rational conclusion is that the 2012 object does not, and can not, exist.However, this answer will probably be thumbs-downed by a couple of totally irrational people.