I'd like to add something --
Another thing that rubbed me wrong about the whole "scoffing" thing. It shows a rashness and arrogance to dismiss something just because of something on the cover, etc. and here's why:
What man is perfect? What man possesses 100% of the truth? Don't even infidels have things to point out, things to teach you?
What if the PDF in question IS mistaken about the theory of gravity, but he has other evidence to point out, which is proof of a DIFFERENT phenomenon, unrelated to Nibiru? Then later on you can take that evidence and use it to underpin something ELSE you read (let's call it Hypothesis B), to add more credence to Hypothesis B, even if the author of Hypothesis B is unaware of that bit of evidence!
For example, Alex Jones is a total "gatekeeper" -- he funnels the curious, those who know something is wrong with "the system" and keeps them in the dark about the MAJOR truths -- the Jєωs control of the financial system, the media, and the world in general, and how they created Communism and Fɾҽҽmαsσɳɾყ (among other things). But Alex Jones has a LOT of truths in his arsenal -- that which he dazzles people with, to get them to follow him. After all, truth has a way of being attractive. Our intellects seek out and latch on to that which is true, just as our Free Wills always seek out that which is good (having a fallen nature, we sometimes choose lesser goods, like tasting every food in the buffet, over greater goods, like eating in moderation)
So a good Catholic can read Alex Jones and take away much truth, even as they go further on their own, and learn THE REST of the truth.
Likewise, I learned a ton about the doctrine of Creation from Mr. Hovind, "Dr. Dino", who has a great website with free videos about the pre-flood earth, dinosaurs, how and why men used to live so long, etc. But he's a protestant preacher! As I've said a thousand times, if we restrict ourselves to traditional Catholics with whom we're in complete agreement, our bookshelf is going to be very, very empty!
In short, it shows a lack of effort, or a lack of love for the truth, to immediately scoff at something which is so highly likely as a chastisement in the near future.
I understand that we only have so much time, and that sometimes we MUST judge a book by its cover to decide what we're going to read, watch, etc. But I don't think information about Nibiru falls into the category of "to be ignored trash". There's too much there to dismiss the whole thing entirely. Best case scenario, the world just gets changed, but doesn't end, on or around Dec 21, 2012. The Mayans were able to understand/predict the movement of this celestial body. How many of us are -- with all our Google, gadgets, PCs, and so-called advanced learning? The Mayans had a "long count" calendar to track things that went WAY ABOVE their own generation -- time periods of centuries. That takes some vision.